雌激素在IBS模型大鼠慢性内脏痛觉敏化中的作用及其机制的研究
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摘要
肠易激综合征(Irritable Bowel Syndrome,IBS)作为临床常见病与多发病,严重影响患者的生存质量,对中国及全球的经济发展产生巨大影响。IBS的病因病理有待探讨,全球目前尚无有效的治疗方法。据报道,IBS女性患者约为男性患者的2~3倍,而且女性患者的症状随月经周期而波动。因此,性别与痛的关系一直受到科学研究者的关注。
女性更易罹患各种疼痛疾病,以往认为,女性容易精神紧张、并易于就诊等是主要原因。但近年的研究提示,男女之间多种精神心理评分和就诊行为等并无差异,而女性的体表痛阈明显低于男性。关于不同性别之间内脏痛阈是否存在差异,罕见研究报道,结果也不一致。但多数学者认同性激素是这种差异的成因之一。多见以动物的动情周期或人的月经周期来研究体内的性激素水平与躯体疼痛关系的报道。但亦有文献报道月经周期不影响热刺激疼痛反应,而血浆高雌激素水平却与体表热刺激疼痛有关。可见生理周期并不能完全反映动物体内的性激素水平。因此,本研究在检测动物的动情周期的同时还直接测量其体内的雌激素水平。
痛觉产生有赖于外周与中枢神经系统的相互作用,性激素可以在多水平上影响痛觉的产生和传递。众多研究表明,NMDA受体的激活在痛觉过敏以及异常痛的产生和维持中发挥着重要的作用。有研究报道,在急性内脏痛动物模型上,雌激素受体和N-甲基-D-门冬氨酸(N-methyl-D-aspartic acid,NMDA)受体的NMDAR1亚单位在脊髓背角上共表达,这支持雌激素对NMDA受体有直接作用。鞘内给予NMDA受体阻断剂(D(-)-2-amino-5-phosphonopentanoicacid,AP-5)能抑制结直肠扩张刺激引发的内脏痛反应,但在高雌激素组大鼠的抑制作用较低雌激素组大鼠的抑制作用弱。研究还发现,雌激素显著增加了腰骶段脊髓中NMDAR1蛋白的表达。以上数据提示,在急性内脏痛动物模型中,雌激素是通过上调NMDA受体的表达来增强脊髓的内脏伤害性传递的。众所周知,慢性内脏痛比急性内脏痛的产生机制要复杂得多,存在慢性痛觉的敏化现象。可以肯定,急性造模的动物不能很好地模拟IBS患者的慢性内脏高敏状态。2000年首次报道的Al-Chaer模型,采用新生期的结直肠扩张刺激,导致成年大鼠出现长期的内脏高敏状态,较好地模仿了IBS患者的特征,为研究IBS发病机制提供了可借鉴的动物模型。该动物模型的神经系统递质与受体功能状态,与急性造模的大鼠之间有很大的不同。在慢性内脏痛的动物模型体内的背根神经节和脊髓内脏相关神经元中,NMDA受体表达增强。在这种情况下,雌激素是否还能通过调节NMDA受体的表达与磷酸化来影响慢性内脏痛呢?
针对以上问题,本研究中检测了雌性IBS模型大鼠的慢性内脏痛与血清雌激素水平,并做了相关性分析,同时比较了高雌激素与低雌激素模型雌鼠的慢性内脏痛反应的程度。为了排除孕激素等其它性激素对雌激素作用的干扰,本研究中只检测去卵巢和去卵巢加上雌激素替代的大鼠,以确定雌激素对慢性内脏痛的作用及其潜在的机制。本研究比较了AP-5(NMDA受体阻断剂)在高、低雌激素IBS模型大鼠上对结直肠扩张刺激的镇痛作用,同时对两组大鼠的脊髓、背根神经节上NMDA受体的表达情况进行检测。本研究将为女性IBS的发病机制的探讨,以及临床上对女性IBS患者的诊治提供理论依据。
1慢性内脏痛大鼠模型的特点及评价
1.1痛阈
大鼠成年后模型雌鼠的痛阈显著低于对照雌鼠,模型雄鼠的痛阈亦显著低于对照雄鼠。雌雄模型大鼠痛阈差异无统计学意义。
1.2腹壁撤退反射评分
在20-60 mmHg压力的结直肠扩张(colorectal distension,CRD)刺激下,模型雄鼠腹壁撤退反射(abdominal withdrawal reflex,AWR)评分明显高于对照雄鼠,80 mmHg压力下的CRD刺激,两组雄鼠的AWR评分趋同,差异消失。在20 mmHg压力的CRD刺激下,模型雌鼠的AWR评分高于对照雌鼠,40-80 mmHg压力的CRD刺激,两组雌鼠的AWR评分趋同,差异消失。
1.3甩尾时间
以(50±1)℃恒温水浴为热致痛源,比较模型与对照大鼠的甩尾时间发现:模型大鼠的平均甩尾时间低于对照大鼠。
1.4结肠组织病理改变
比较对照和模型大鼠远端降结肠和直肠的局部组织学的病理改变。结果显示,对照与模型大鼠经过肉眼观察和显微镜检查,均未见明显病理改变。
1.5模型雌鼠动情周期与血清雌激素水平的关系
观察19只模型雌鼠的阴道涂片,分别在其处于动情前期(P)、动情期(E)、动情后期(M)、间情期(D)时,采集大鼠血液测定雌激素水平。雌鼠在P期的雌激素水平明显高于其它各期,此外,其它各期雌激素水平之间无显著差异。
1.6动物分组
模型组与对照组中又各自设立高雌激素组(E2组)与低雌激素组(OVx组),两组大鼠均去卵巢,E2组大鼠在测量内脏痛前两天腹腔注射雌激素100μg,OVx组大鼠则不补充雌激素。
2慢性内脏痛与血清雌激素水平的关系
2.1雌雄模型大鼠的放电比较
大鼠放电反应随CRD压力增加而增加,各压力下放电的差异具有统计学意义。在15 mmHg,30 mmHg,45 mmHg的CRD刺激下,模型雌鼠腹外斜肌放电反应均高于模型雄鼠。
2.2模型雌鼠的腹外斜肌放电与血清雌激素水平关系
模型雌鼠的血清雌激素水平为115.70±26.34 pmol/L,最小值84.50pmol/L,最大值154.20 pmol/L。在20~80 mmHg压力的CRD刺激下,模型雌鼠的腹外斜肌放电平均峰值与血清雌激素水平正相关。
2.3高雌激素大鼠与去卵巢大鼠内脏痛敏的比较
2.3.1大鼠的阴道涂片结果
高雌激素大鼠的阴道涂片见多边形的角化细胞,体积大,呈动情期表现,表明其体内雌激素水平高。去卵巢大鼠的阴道涂片见圆形上皮细胞,体积小,呈间情期表现,表明其体内雌激素水平低。
2.3.2腹外斜肌放电水平比较
在20mmHg的CRD压力下,模型E2组大鼠的的腹外斜肌放电水平高于模型OVx组大鼠,两组差别有显著性意义。另一方面,在20mmHg的CRD压力下,对照E2组大鼠的的腹外斜肌放电水平与对照OVx组大鼠之间没有明显差别。说明雌激素可加重模型大鼠内脏痛觉敏感性。
3 AP-5鞘内给药对慢性内脏痛的抑制作用与血清雌激素水平的关系
3.1 AP-5椎管给药的抑制作用
3.1.1 AP-5抑制作用的时效关系
AP-5的抑制作用在5min时最强,随时间渐渐减弱。在模型OVx组与E2组,给药5min、10min、15min后的内脏运动反应程度均低于给药前水平,差别有显著性意义。说明AP-5对模型大鼠的内脏痛有明显的抑制作用。
3.1.2 AP-5对OVx组与E2组模型大鼠抑制作用的比较
OVx组与E2组在给药5min、10min、15min、30min后,抑制百分比的差别无显著性意义。
3.2 NMDAR1受体在OVx组与E2组模型大鼠的表达
3.2.1 E2大鼠与OVx大鼠脊髓背根神经节NMDAR1受体表达
采用免疫组织化学方法,比较E2大鼠与OVx大鼠背根神经节NMDAR1的表达。结果显示,大鼠腰骶段脊髓背根神经节阳性细胞,多为圆形或椭圆形的神经元,胞质呈棕黄色,呈强阳性表达。图像分析结果显示,与OVx大鼠相比,E2大鼠NMDAR1受体表达的平均光密度无明显差别。
3.2.2 E2大鼠与OVx大鼠腰骶段脊髓NMDAR1受体表达
采用免疫组织化学方法,比较E2大鼠与OVx大鼠脊髓背角神经元NMDAR1的表达。结果显示,E2大鼠与OVx大鼠腰骶段脊髓均可见NMDAR1阳性表达,胞质呈棕黄色,为强阳性表达。图像分析结果显示,E2大鼠腰骶段NMDAR1受体表达的平均光密度与OVx大鼠无明显差异。
3.2.3肠道中NMDAR1受体表达
在大鼠肠道内在神经丛中可见NMDAR1阳性表达,胞质呈棕黄色。
综上所述,本工作提示:
1.雌雄大鼠新生期接受结直肠扩张刺激,成年时(8 wk后)都可引发慢性内脏高敏,且其结直肠局部组织未见明显的病理改变,提示本模型可作为IBS样功能性慢性内脏痛的研究模型。
2.雌性模型大鼠内脏疼痛的敏感性高于雄性模型大鼠,且与血清雌激素水平正相关,高雌激素模型大鼠的内脏痛敏感性高于去卵巢模型大鼠,提示雌激素增加了直肠感觉的敏感性。
3.NMDA受体拈抗剂AP-5椎管给药可减轻内脏运动反应,且减轻的程度在去卵巢大鼠与高雌激素大鼠并无差别,两组大鼠的脊髓背角NMDAR1的表达差别无显著性。提示雌激素可能没有通过调节脊髓背角NMDAR1表达的改变在雌鼠慢性内脏痛中枢敏化机制中发挥作用。
Irritable bowel syndrome(IBS) is a common and frequently encountered disease,lt has greatly affected the life quality of the patients,and also has great influence on Chinese and global social economy.The etiology and pathology of IBS are still not clear,so we still have no effective treatment for this disease.IBS is 2 - 3 times more prevalent in women than in men.The severity of pain symptoms in women with IBS fluctuates with the menstrual cycle.Therefore many researchers paid close attention to the relation between gender and pain.
Women are easier to suffer from different kinds of pain disease.It was assumed that women are easier to be nervous and to go to see a doctor was the main reason.But the recent reports suggested,there were no difference in many psychiatry and psychology scores between men and women. The body surface pain threshold of women is significantly lower than that of men.But there were few researches on whether there was difference in visceral pain threshold between man and woman,and the results of these researches were contradictory.In the researches which considered there were difference in visceral pain threshold between man and woman,most of them thought gonadal hormone was the reason of the difference.Many researchers only used the estrous cycle of animal or the menstrual cycle of human being to deduce the gonadal hormone level,but didn't measure the gonadal hormone level directly.Although there is some corresponding relation between these physiological cycle and the gonadal hormone level, they can' t reflect the gonadal hormone level completely.As it was reported,though menstrual cycle didn't influence thermo-pain refleetion,but high estrogen level inplasma didhaverelationwithbody surface thermo-pain.So it is more convinced to measure estrogen level than to deduce the gonadal hormone level by physiological cycle.In this study,the estrogen level as well as the estrus cycle of rats were measured.
There was pheriphery and central nervous system interaction in pain transmit.Gonadal hormone can interact with this system on different levels.Many studies indicated that the activation of NMDA receptors played important roles in the producing and maintaining of hyperalgia and allodynia.Bin Tang reported in acute visceral pain animal model,estrogen receptor alpha and the NMDAR1 subunit of the NMDA receptor were co-expressed in dorsal horn neurons,supporting a direct action of estradiol on NMDA receptors.Intrathecal administration of the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid(AP-5) dose-dependently attenuated the visceromotor response with greater potency in ovariectomized(OVx) rats compared to OVx with estradiol replacement(E2) rats.Estradiol significantly increased protein expression of NMDAR1 in the lumbosacral spinal cord compared to OVx rats. These datas suggest that estradiol increases spinal processing of visceral nociception by increasing NMDA receptor NMDAR1 subunit expression in acute visceral pain animal model.As we all know,chronic visceral pain has chronic visceral hypersensitivity,the pathogenesy of which is by far more complex than those of acute visceral pain.Acute visceral pain model can hardly simulate the chronic visceral hypersensitivity state of IBS patients.In 2000 Al-Chaer first reported a new model.It was constructed by neonatal mechanical colorectal irritants,the adult rats had visceral hypersensitivity for a long time. Al-Chaer' s model can simulate the characteristics of IBS patients.It provided a good animal model for the research on IBS pathogenesy.The nervous system transmitters and receptors functional status of this model is greatly different from those of the acute model.NMDA receptor expressions in the dorsal root gangalia(DRG) and spinal cord visceral correlated neurons of this chronic visceral pain animal model were upregulated.Under this condition,can estradiol influence chronic visceral pain by regulate the expression and phosphorylation of NMDA receptors?
In this study,the chronic visceral pain and serum estrogen level of female IBS model rats were detected,the relation between them were analyzed.The chronic visceral pain degree of high estrogen and low estrogen female model rats were compared,ln order to avoid the interference of progestogen and other gonadal hormones,only ovariectomized rats and ovariectomized with estrogen substitute rats were used to determine the effect of estrogen on chronic visceral pain and the potential mechanism of it.The inhibit effects of AP-5(NMDA receptor antagonist) on chronic visceral pain and the NMDA receptor expression in the lumbosacral spinal cord and DRG between OVx rats and E2 rats were compared.This study will provide theory basis to the pathogenetic research and the clinical diagnosis and therapy of female IBS patients.
1 The characteristics and evaluation of the chronic visceral pain model
1.1 Pain threshold
Male and female model rats were made by improved Al-Chare' s method. The pain thresholds of model female rats were significantly lower than those of control female rats.The pain thresholds of model male rats were significantly lower than those of control male rats.No significant difference was found between the male and female model rats' pain thresholds.
1.2 Abdominal withdrawal reflex scores
The AWR scores of model male rats were significantly higher than those of control male rats under 20-60mmHg CRD stimulation.The difference of AWR scores disappeared under 80 mmHg CRD stimulation.The AWR scores of model female rats were significantly higher than those of control female rats under 20 mmHg CRD stimulation.The difference of AWR scores disappeared under 40-80 mmHg CRD stimulation.
1.3 Tail-flick latency
The tail-flick latency of both model and control rats were compared.The tail-flick latency of model rats were significantly shorter than those of the control rats.
1.4 The colorectal pathological change
The distal colon descendens and rectal topographic histology of control rats and model rats were compared.Neither control nor model rats showed apparent pathological change under macroscopic observation and microscopic examination.
1.5 The relation between serum estrogen level and estrus cycle of the female model rats
Vaginal smear of 19 female model rats was observed.Serum estrogen level was detected in preoestrus,estrus,metoestrus and dioestrus.The serum estrogen level in preoestrus was significantly higher than those in estrus,metoestrus and dioestrus.No significant difference was found among the serum estrogen levels in estrus,metoestrus and dioestrus.
1.6 Grouping of the animals
Both model and control rats were divided into high estrogen(E2) group and low estrogen(OVx ) group.Both E2 and OVx rats were ovariectomized.Only E2 rats accepted estrogen(100μg,i.p.)two days before visceral pain measurement.
2 The correlation between visceral pain and serum estrogen level
2.1 The electric discharge of male and female model rats
Change rate of electric discharge increased with CRD pressure.The difference of electric discharge change rates among each pressure was significant.Under 15 mmHg,30 mmHg,45 mmHg CRD pressure,electric discharge of EOMA of the model female rats was higher than those of the model male rats.
2.2 The relation between electric discharge of EOMA of model female rats and their serum estrogen level
The mean serum estrogen level of model female rat was 115.70±26.34 pmol/L,the minimun value was 84.50 pmol/L,the maximum was 154.20 pmol/L. A positive relation was detected between the electric discharge of EOMA of model female rats and their serum estrogen level under 20~80mmHg CRD pressure.
2.3 The comparism of visceral pain sensitivity between high estrogen rats and OVx rats
2.3.1 Vaginal smear results of rats
Under microscopic examination,vaginal smear of E2 rats(high estrogen) showed many big polygonal keratinocytes,which is a typical estrous manifestation.This indicated high estrogen level in the rat,which can promote the maturation and cornification of the vagina epithelium cells. Vaginal smear of OVx rats(low estrogen) showed many small round epithelium cells,which is a typical dioestrus manifestation.This indicated low estrogen level in the rat.
2.3.2 Comparism of electric discharge of EOMA
Under 20mmHg CRD pressure,the electric discharge of EOMAof E2 model rats was significantly higher than those of the OVx model rats.This demonstrated the visceral pain of E2 model rat was more sensitive than those of the OVx model rats.High estrogen level can lead to visceral pain sensitization.On the other hand,the electric discharge of EOMA of E2 control rats and OVx control rats didn't show significant difference under 20mmHg CRD pressure.This indicated estrogen can add to the high visceral pain sensitivity of model rats.
3 The inhibited effect of chronic visceral pain by intrathecal administration of AP-5 and its relation with estrogen level.
3.1 Intrathecal administration of AP-5 attenuated the visceromotor response
3.1.1 Time-effect relationship of AP-5 inhibition
The peak effect occurred 5 min after AP-5 administration.The effect decreased as time went on.5min、10min、15min after AP-5 administration, the visceromotor response were all significantly lower than those before AP-5 administration.This demonstrated intrathecal administration of AP-5 significantly attenuated the visceral pain of rats.
3.1.2 The inhibited effect of intrathecal AP-5 in OVx and E2 model rats.
5min、10min、15min、30min after AP-5 administration,the inhibited percent of OVx and E2 model ratsdidn' t show any significant difference.
3.2 The expression of NMDARI in OVx and E2 model rats
3.2.1 The expression of NMDARI in OVx and E2 model rats' DRG
The NMDARI expression in OVx and E2 model rats' DRG were compared by immunohistochemistry.The positive cells in the rat' s lumbar and sacral DRG were round or elliptic,their kytoplasm stainedbrown.Image analysis showed,there were no significant difference between the average opticals which stands for the NMDAR1 expression in E2 rats and those of the OVx rats.
3.2.2 The lumbar and sacral spinal cord expression of NMDAR1 in E2 and OVx rats
The NMDAR1 expression in OVx and E2 model rats' spinal cord dorsal horn neurons were compared by immunohistochemistry.NMDARI expression in both E2 and OVx rats' lumbar and sacral spinal cord were found.The kytoplasm stained brown.Image analysis showed,there were no significant difference between the average opticals which standed for the NMDAR1 expression in E2 rats' lumbar and sacral spinal cord and those of the OVx rats.
3.2.3 Expression of NMDAR1 in intestinal tract
NMDAR1 expression in intestinal tract internal nerve plexus was found.Its kytoplasm stained brown.
In conclusion,this study indicates:
1.Neonatal colonrectal distension can lead to chronic visceral sensitization in adult(after 8 wk) male and female rats.There was no conspicuous pathological change in colorectal topographic histology.This indicated that this model could be used to do research on IBS like chronic functional visceral pain.
2.The visceral pain sensitivity of female model rats was higher than that of the male model rats.The discharging reactions of female rats' EOMA to CRD were positively related to serum estrogen level.Visceral pain sensitivity of E2 model rats was higher than that of OVx model rats.These results all support the suppose that estrogen can increase colorectal sensitivity.
3.Intrathecal administration of AP-5(NMDA receptor antagonist) attenuated the visceromotor response.There was no significant difference between the effect of AP-5 in E2 and OVx rats.No significant difference was found between the NMDARI expression in E2 and OVx rats' spinal cord dorsal horn neurons.These datas suggest that estradiol doesn't increase processing of visceral nociception by increasing NMDA receptor NMDAR1 subunit expression in spinal cord.
女性更易罹患各种疼痛疾病,以往认为,女性容易精神紧张、并易于就诊等是主要原因。但近年的研究提示,男女之间多种精神心理评分和就诊行为等并无差异,而女性的体表痛阈明显低于男性。关于不同性别之间内脏痛阈是否存在差异,罕见研究报道,结果也不一致。但多数学者认同性激素是这种差异的成因之一。多见以动物的动情周期或人的月经周期来研究体内的性激素水平与躯体疼痛关系的报道。但亦有文献报道月经周期不影响热刺激疼痛反应,而血浆高雌激素水平却与体表热刺激疼痛有关。可见生理周期并不能完全反映动物体内的性激素水平。因此,本研究在检测动物的动情周期的同时还直接测量其体内的雌激素水平。
痛觉产生有赖于外周与中枢神经系统的相互作用,性激素可以在多水平上影响痛觉的产生和传递。众多研究表明,NMDA受体的激活在痛觉过敏以及异常痛的产生和维持中发挥着重要的作用。有研究报道,在急性内脏痛动物模型上,雌激素受体和N-甲基-D-门冬氨酸(N-methyl-D-aspartic acid,NMDA)受体的NMDAR1亚单位在脊髓背角上共表达,这支持雌激素对NMDA受体有直接作用。鞘内给予NMDA受体阻断剂(D(-)-2-amino-5-phosphonopentanoicacid,AP-5)能抑制结直肠扩张刺激引发的内脏痛反应,但在高雌激素组大鼠的抑制作用较低雌激素组大鼠的抑制作用弱。研究还发现,雌激素显著增加了腰骶段脊髓中NMDAR1蛋白的表达。以上数据提示,在急性内脏痛动物模型中,雌激素是通过上调NMDA受体的表达来增强脊髓的内脏伤害性传递的。众所周知,慢性内脏痛比急性内脏痛的产生机制要复杂得多,存在慢性痛觉的敏化现象。可以肯定,急性造模的动物不能很好地模拟IBS患者的慢性内脏高敏状态。2000年首次报道的Al-Chaer模型,采用新生期的结直肠扩张刺激,导致成年大鼠出现长期的内脏高敏状态,较好地模仿了IBS患者的特征,为研究IBS发病机制提供了可借鉴的动物模型。该动物模型的神经系统递质与受体功能状态,与急性造模的大鼠之间有很大的不同。在慢性内脏痛的动物模型体内的背根神经节和脊髓内脏相关神经元中,NMDA受体表达增强。在这种情况下,雌激素是否还能通过调节NMDA受体的表达与磷酸化来影响慢性内脏痛呢?
针对以上问题,本研究中检测了雌性IBS模型大鼠的慢性内脏痛与血清雌激素水平,并做了相关性分析,同时比较了高雌激素与低雌激素模型雌鼠的慢性内脏痛反应的程度。为了排除孕激素等其它性激素对雌激素作用的干扰,本研究中只检测去卵巢和去卵巢加上雌激素替代的大鼠,以确定雌激素对慢性内脏痛的作用及其潜在的机制。本研究比较了AP-5(NMDA受体阻断剂)在高、低雌激素IBS模型大鼠上对结直肠扩张刺激的镇痛作用,同时对两组大鼠的脊髓、背根神经节上NMDA受体的表达情况进行检测。本研究将为女性IBS的发病机制的探讨,以及临床上对女性IBS患者的诊治提供理论依据。
1慢性内脏痛大鼠模型的特点及评价
1.1痛阈
大鼠成年后模型雌鼠的痛阈显著低于对照雌鼠,模型雄鼠的痛阈亦显著低于对照雄鼠。雌雄模型大鼠痛阈差异无统计学意义。
1.2腹壁撤退反射评分
在20-60 mmHg压力的结直肠扩张(colorectal distension,CRD)刺激下,模型雄鼠腹壁撤退反射(abdominal withdrawal reflex,AWR)评分明显高于对照雄鼠,80 mmHg压力下的CRD刺激,两组雄鼠的AWR评分趋同,差异消失。在20 mmHg压力的CRD刺激下,模型雌鼠的AWR评分高于对照雌鼠,40-80 mmHg压力的CRD刺激,两组雌鼠的AWR评分趋同,差异消失。
1.3甩尾时间
以(50±1)℃恒温水浴为热致痛源,比较模型与对照大鼠的甩尾时间发现:模型大鼠的平均甩尾时间低于对照大鼠。
1.4结肠组织病理改变
比较对照和模型大鼠远端降结肠和直肠的局部组织学的病理改变。结果显示,对照与模型大鼠经过肉眼观察和显微镜检查,均未见明显病理改变。
1.5模型雌鼠动情周期与血清雌激素水平的关系
观察19只模型雌鼠的阴道涂片,分别在其处于动情前期(P)、动情期(E)、动情后期(M)、间情期(D)时,采集大鼠血液测定雌激素水平。雌鼠在P期的雌激素水平明显高于其它各期,此外,其它各期雌激素水平之间无显著差异。
1.6动物分组
模型组与对照组中又各自设立高雌激素组(E2组)与低雌激素组(OVx组),两组大鼠均去卵巢,E2组大鼠在测量内脏痛前两天腹腔注射雌激素100μg,OVx组大鼠则不补充雌激素。
2慢性内脏痛与血清雌激素水平的关系
2.1雌雄模型大鼠的放电比较
大鼠放电反应随CRD压力增加而增加,各压力下放电的差异具有统计学意义。在15 mmHg,30 mmHg,45 mmHg的CRD刺激下,模型雌鼠腹外斜肌放电反应均高于模型雄鼠。
2.2模型雌鼠的腹外斜肌放电与血清雌激素水平关系
模型雌鼠的血清雌激素水平为115.70±26.34 pmol/L,最小值84.50pmol/L,最大值154.20 pmol/L。在20~80 mmHg压力的CRD刺激下,模型雌鼠的腹外斜肌放电平均峰值与血清雌激素水平正相关。
2.3高雌激素大鼠与去卵巢大鼠内脏痛敏的比较
2.3.1大鼠的阴道涂片结果
高雌激素大鼠的阴道涂片见多边形的角化细胞,体积大,呈动情期表现,表明其体内雌激素水平高。去卵巢大鼠的阴道涂片见圆形上皮细胞,体积小,呈间情期表现,表明其体内雌激素水平低。
2.3.2腹外斜肌放电水平比较
在20mmHg的CRD压力下,模型E2组大鼠的的腹外斜肌放电水平高于模型OVx组大鼠,两组差别有显著性意义。另一方面,在20mmHg的CRD压力下,对照E2组大鼠的的腹外斜肌放电水平与对照OVx组大鼠之间没有明显差别。说明雌激素可加重模型大鼠内脏痛觉敏感性。
3 AP-5鞘内给药对慢性内脏痛的抑制作用与血清雌激素水平的关系
3.1 AP-5椎管给药的抑制作用
3.1.1 AP-5抑制作用的时效关系
AP-5的抑制作用在5min时最强,随时间渐渐减弱。在模型OVx组与E2组,给药5min、10min、15min后的内脏运动反应程度均低于给药前水平,差别有显著性意义。说明AP-5对模型大鼠的内脏痛有明显的抑制作用。
3.1.2 AP-5对OVx组与E2组模型大鼠抑制作用的比较
OVx组与E2组在给药5min、10min、15min、30min后,抑制百分比的差别无显著性意义。
3.2 NMDAR1受体在OVx组与E2组模型大鼠的表达
3.2.1 E2大鼠与OVx大鼠脊髓背根神经节NMDAR1受体表达
采用免疫组织化学方法,比较E2大鼠与OVx大鼠背根神经节NMDAR1的表达。结果显示,大鼠腰骶段脊髓背根神经节阳性细胞,多为圆形或椭圆形的神经元,胞质呈棕黄色,呈强阳性表达。图像分析结果显示,与OVx大鼠相比,E2大鼠NMDAR1受体表达的平均光密度无明显差别。
3.2.2 E2大鼠与OVx大鼠腰骶段脊髓NMDAR1受体表达
采用免疫组织化学方法,比较E2大鼠与OVx大鼠脊髓背角神经元NMDAR1的表达。结果显示,E2大鼠与OVx大鼠腰骶段脊髓均可见NMDAR1阳性表达,胞质呈棕黄色,为强阳性表达。图像分析结果显示,E2大鼠腰骶段NMDAR1受体表达的平均光密度与OVx大鼠无明显差异。
3.2.3肠道中NMDAR1受体表达
在大鼠肠道内在神经丛中可见NMDAR1阳性表达,胞质呈棕黄色。
综上所述,本工作提示:
1.雌雄大鼠新生期接受结直肠扩张刺激,成年时(8 wk后)都可引发慢性内脏高敏,且其结直肠局部组织未见明显的病理改变,提示本模型可作为IBS样功能性慢性内脏痛的研究模型。
2.雌性模型大鼠内脏疼痛的敏感性高于雄性模型大鼠,且与血清雌激素水平正相关,高雌激素模型大鼠的内脏痛敏感性高于去卵巢模型大鼠,提示雌激素增加了直肠感觉的敏感性。
3.NMDA受体拈抗剂AP-5椎管给药可减轻内脏运动反应,且减轻的程度在去卵巢大鼠与高雌激素大鼠并无差别,两组大鼠的脊髓背角NMDAR1的表达差别无显著性。提示雌激素可能没有通过调节脊髓背角NMDAR1表达的改变在雌鼠慢性内脏痛中枢敏化机制中发挥作用。
Irritable bowel syndrome(IBS) is a common and frequently encountered disease,lt has greatly affected the life quality of the patients,and also has great influence on Chinese and global social economy.The etiology and pathology of IBS are still not clear,so we still have no effective treatment for this disease.IBS is 2 - 3 times more prevalent in women than in men.The severity of pain symptoms in women with IBS fluctuates with the menstrual cycle.Therefore many researchers paid close attention to the relation between gender and pain.
Women are easier to suffer from different kinds of pain disease.It was assumed that women are easier to be nervous and to go to see a doctor was the main reason.But the recent reports suggested,there were no difference in many psychiatry and psychology scores between men and women. The body surface pain threshold of women is significantly lower than that of men.But there were few researches on whether there was difference in visceral pain threshold between man and woman,and the results of these researches were contradictory.In the researches which considered there were difference in visceral pain threshold between man and woman,most of them thought gonadal hormone was the reason of the difference.Many researchers only used the estrous cycle of animal or the menstrual cycle of human being to deduce the gonadal hormone level,but didn't measure the gonadal hormone level directly.Although there is some corresponding relation between these physiological cycle and the gonadal hormone level, they can' t reflect the gonadal hormone level completely.As it was reported,though menstrual cycle didn't influence thermo-pain refleetion,but high estrogen level inplasma didhaverelationwithbody surface thermo-pain.So it is more convinced to measure estrogen level than to deduce the gonadal hormone level by physiological cycle.In this study,the estrogen level as well as the estrus cycle of rats were measured.
There was pheriphery and central nervous system interaction in pain transmit.Gonadal hormone can interact with this system on different levels.Many studies indicated that the activation of NMDA receptors played important roles in the producing and maintaining of hyperalgia and allodynia.Bin Tang reported in acute visceral pain animal model,estrogen receptor alpha and the NMDAR1 subunit of the NMDA receptor were co-expressed in dorsal horn neurons,supporting a direct action of estradiol on NMDA receptors.Intrathecal administration of the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid(AP-5) dose-dependently attenuated the visceromotor response with greater potency in ovariectomized(OVx) rats compared to OVx with estradiol replacement(E2) rats.Estradiol significantly increased protein expression of NMDAR1 in the lumbosacral spinal cord compared to OVx rats. These datas suggest that estradiol increases spinal processing of visceral nociception by increasing NMDA receptor NMDAR1 subunit expression in acute visceral pain animal model.As we all know,chronic visceral pain has chronic visceral hypersensitivity,the pathogenesy of which is by far more complex than those of acute visceral pain.Acute visceral pain model can hardly simulate the chronic visceral hypersensitivity state of IBS patients.In 2000 Al-Chaer first reported a new model.It was constructed by neonatal mechanical colorectal irritants,the adult rats had visceral hypersensitivity for a long time. Al-Chaer' s model can simulate the characteristics of IBS patients.It provided a good animal model for the research on IBS pathogenesy.The nervous system transmitters and receptors functional status of this model is greatly different from those of the acute model.NMDA receptor expressions in the dorsal root gangalia(DRG) and spinal cord visceral correlated neurons of this chronic visceral pain animal model were upregulated.Under this condition,can estradiol influence chronic visceral pain by regulate the expression and phosphorylation of NMDA receptors?
In this study,the chronic visceral pain and serum estrogen level of female IBS model rats were detected,the relation between them were analyzed.The chronic visceral pain degree of high estrogen and low estrogen female model rats were compared,ln order to avoid the interference of progestogen and other gonadal hormones,only ovariectomized rats and ovariectomized with estrogen substitute rats were used to determine the effect of estrogen on chronic visceral pain and the potential mechanism of it.The inhibit effects of AP-5(NMDA receptor antagonist) on chronic visceral pain and the NMDA receptor expression in the lumbosacral spinal cord and DRG between OVx rats and E2 rats were compared.This study will provide theory basis to the pathogenetic research and the clinical diagnosis and therapy of female IBS patients.
1 The characteristics and evaluation of the chronic visceral pain model
1.1 Pain threshold
Male and female model rats were made by improved Al-Chare' s method. The pain thresholds of model female rats were significantly lower than those of control female rats.The pain thresholds of model male rats were significantly lower than those of control male rats.No significant difference was found between the male and female model rats' pain thresholds.
1.2 Abdominal withdrawal reflex scores
The AWR scores of model male rats were significantly higher than those of control male rats under 20-60mmHg CRD stimulation.The difference of AWR scores disappeared under 80 mmHg CRD stimulation.The AWR scores of model female rats were significantly higher than those of control female rats under 20 mmHg CRD stimulation.The difference of AWR scores disappeared under 40-80 mmHg CRD stimulation.
1.3 Tail-flick latency
The tail-flick latency of both model and control rats were compared.The tail-flick latency of model rats were significantly shorter than those of the control rats.
1.4 The colorectal pathological change
The distal colon descendens and rectal topographic histology of control rats and model rats were compared.Neither control nor model rats showed apparent pathological change under macroscopic observation and microscopic examination.
1.5 The relation between serum estrogen level and estrus cycle of the female model rats
Vaginal smear of 19 female model rats was observed.Serum estrogen level was detected in preoestrus,estrus,metoestrus and dioestrus.The serum estrogen level in preoestrus was significantly higher than those in estrus,metoestrus and dioestrus.No significant difference was found among the serum estrogen levels in estrus,metoestrus and dioestrus.
1.6 Grouping of the animals
Both model and control rats were divided into high estrogen(E2) group and low estrogen(OVx ) group.Both E2 and OVx rats were ovariectomized.Only E2 rats accepted estrogen(100μg,i.p.)two days before visceral pain measurement.
2 The correlation between visceral pain and serum estrogen level
2.1 The electric discharge of male and female model rats
Change rate of electric discharge increased with CRD pressure.The difference of electric discharge change rates among each pressure was significant.Under 15 mmHg,30 mmHg,45 mmHg CRD pressure,electric discharge of EOMA of the model female rats was higher than those of the model male rats.
2.2 The relation between electric discharge of EOMA of model female rats and their serum estrogen level
The mean serum estrogen level of model female rat was 115.70±26.34 pmol/L,the minimun value was 84.50 pmol/L,the maximum was 154.20 pmol/L. A positive relation was detected between the electric discharge of EOMA of model female rats and their serum estrogen level under 20~80mmHg CRD pressure.
2.3 The comparism of visceral pain sensitivity between high estrogen rats and OVx rats
2.3.1 Vaginal smear results of rats
Under microscopic examination,vaginal smear of E2 rats(high estrogen) showed many big polygonal keratinocytes,which is a typical estrous manifestation.This indicated high estrogen level in the rat,which can promote the maturation and cornification of the vagina epithelium cells. Vaginal smear of OVx rats(low estrogen) showed many small round epithelium cells,which is a typical dioestrus manifestation.This indicated low estrogen level in the rat.
2.3.2 Comparism of electric discharge of EOMA
Under 20mmHg CRD pressure,the electric discharge of EOMAof E2 model rats was significantly higher than those of the OVx model rats.This demonstrated the visceral pain of E2 model rat was more sensitive than those of the OVx model rats.High estrogen level can lead to visceral pain sensitization.On the other hand,the electric discharge of EOMA of E2 control rats and OVx control rats didn't show significant difference under 20mmHg CRD pressure.This indicated estrogen can add to the high visceral pain sensitivity of model rats.
3 The inhibited effect of chronic visceral pain by intrathecal administration of AP-5 and its relation with estrogen level.
3.1 Intrathecal administration of AP-5 attenuated the visceromotor response
3.1.1 Time-effect relationship of AP-5 inhibition
The peak effect occurred 5 min after AP-5 administration.The effect decreased as time went on.5min、10min、15min after AP-5 administration, the visceromotor response were all significantly lower than those before AP-5 administration.This demonstrated intrathecal administration of AP-5 significantly attenuated the visceral pain of rats.
3.1.2 The inhibited effect of intrathecal AP-5 in OVx and E2 model rats.
5min、10min、15min、30min after AP-5 administration,the inhibited percent of OVx and E2 model ratsdidn' t show any significant difference.
3.2 The expression of NMDARI in OVx and E2 model rats
3.2.1 The expression of NMDARI in OVx and E2 model rats' DRG
The NMDARI expression in OVx and E2 model rats' DRG were compared by immunohistochemistry.The positive cells in the rat' s lumbar and sacral DRG were round or elliptic,their kytoplasm stainedbrown.Image analysis showed,there were no significant difference between the average opticals which stands for the NMDAR1 expression in E2 rats and those of the OVx rats.
3.2.2 The lumbar and sacral spinal cord expression of NMDAR1 in E2 and OVx rats
The NMDAR1 expression in OVx and E2 model rats' spinal cord dorsal horn neurons were compared by immunohistochemistry.NMDARI expression in both E2 and OVx rats' lumbar and sacral spinal cord were found.The kytoplasm stained brown.Image analysis showed,there were no significant difference between the average opticals which standed for the NMDAR1 expression in E2 rats' lumbar and sacral spinal cord and those of the OVx rats.
3.2.3 Expression of NMDAR1 in intestinal tract
NMDAR1 expression in intestinal tract internal nerve plexus was found.Its kytoplasm stained brown.
In conclusion,this study indicates:
1.Neonatal colonrectal distension can lead to chronic visceral sensitization in adult(after 8 wk) male and female rats.There was no conspicuous pathological change in colorectal topographic histology.This indicated that this model could be used to do research on IBS like chronic functional visceral pain.
2.The visceral pain sensitivity of female model rats was higher than that of the male model rats.The discharging reactions of female rats' EOMA to CRD were positively related to serum estrogen level.Visceral pain sensitivity of E2 model rats was higher than that of OVx model rats.These results all support the suppose that estrogen can increase colorectal sensitivity.
3.Intrathecal administration of AP-5(NMDA receptor antagonist) attenuated the visceromotor response.There was no significant difference between the effect of AP-5 in E2 and OVx rats.No significant difference was found between the NMDARI expression in E2 and OVx rats' spinal cord dorsal horn neurons.These datas suggest that estradiol doesn't increase processing of visceral nociception by increasing NMDA receptor NMDAR1 subunit expression in spinal cord.
引文
[1]尉秀清,陈旻湖,王锦辉,胡品津.广州市居民肠易激综合征及功能性便秘的流行病学调查.[J]中华内科杂志 2001;40:517-520
[2]Berkley KJ.Sex differences in pain.[J]Behav Brain Sci 1997;20:371 - 380.
[3]Mayer EA,Berman S,Chang L,Naliboff BD.Sex-based differences in gastrointestinal pain.[J]Eur J Pain 2004;8:451-63.
[4]Case AM,Reid RL.Effects of the menstrual cycle on medical disorders.[J]Arch Intern Med 1998;158:1405- 1412.
[5]Moore J,Barlow D,Jewell D,Kennedy S Do gastrointestinal symptoms vary with the menstrual cycle?[J]Br J Obstet Gynaecol 1998;105:1322 -1325.
[6]Toner BB,Akman D.Gender role and irritable bowel syndrome:literature review and hypothesis.[J]Am J Gastroenterol 2000;95:11- 16.
[7]Prior A,Stanley KM,Smith AR,Read NW.Relation between hysterectomy and the irritable bowel:a prospective study.[J]Gut 1992;33:814-817.
[8]Mathias JR,Clench MH,Reeves-Darby VG,Fox LM,Hsu PH,Roberts PH,Smith LL,Stiglich NJ.Effect of leuprolide acetate in patients with moderate to severe functional bowel disease.Double-blind,placebocontrolled study.[J]Dig Dis Sci 1994;39:1155- 1162
[9]Sapsed-Byrne S,Ma D,Ridout D,Holdcroft A.Estrous cycle phase variations in visceromotor and cardiovascular responses to colonic distension in the anesthetized rat.[J]Brain Res 1996;742:10-6.
[10]Holdcroft A,Sapsed-Byrne S,Ma D,Hammal D,Forsling ML.Sex and oestrous cycle differences in visceromotor responses and vasopressin release in response to colonic distention in male and female rats anesthetized with halothane.[J]Br J Anaesth 2000;85:907-910
[11]Robbins A,Berkley KJ,Sato Y.Estrous cycle variation of afferent fibers supplying reproductive organs in the female rat.[J]Brain Res 1992;596:353-6.
[12]Bradshaw HB,Temple JL,Wood E,Berkley KJ.Estrous variations in behavioral responses to vaginal and uterine distention in the rat.[J]Pain 1999;82:187-97.
[13]Forman LJ,Tingle V,Estilow S,Cater J.The response to analgesia testing is affected by gonadal steroids in the rat.[J]Life Sci 1989;45:447-454.
[14]Ratka A,Simpkins JW.Effects of estradiol and progesterone on the sensitivity to pain and on morphine-induced antinociception in female rats.[J]Horm Behav 1991;25:217-228.
[15]Kayser V,Berkley KJ,Keita H,Gautron M,Guilbaud G.Estrous and sex variations in vocalization thresholds to hindpaw and tail pressure stimulation in the rat.[J]Brain Res 1996;742:352-354.
[16]Bradshaw H,Miller J,Ling QD,Malsnee K,RudaMA.Sex differences and phases of the estrous cycle alter the response of spinal cord dynorphin neurons to peripheral inflammation and hyperalgesia.[J]Pain 2000;85:93-99.
[17]Bereiter DA.Sex differences in brainstem neural activation after injury to the TMJ region.[J]Cells Tissues Organs 2001;169:226-237.
[18]Ji Y,Murphy AZ,Traub RJ.Estrogen modulates the visceromotor reflex and responses of spinal dorsal horn neurons to colorectal stimulation in the rat.[J].J Neurosci 2003;23:3908-15.
[19]Ji Y,Tang B,Traub RJ.Modulatory effects of estrogen and progesterone on colorectal hyperalgesia in the rat.[J]Pain 2005;117:433-442.
[20]Martinez-Gomez M,Cruz Y,Salas M,Hudson R,Pacheco P Assessing pain threshold in the rat:changes with estrus and time of day.[J]Physiol Behav 1994;55:651-657.
[21]Giamberardino MA,Affaitati G,Valente R,Iezzi S,Vecchiet L Changes in visceral pain reactivity as a function of estrous cycle in female rats with artificial ureteral calculosis.[J]Brain Res 1997;774:234-238.
[22]Gintzler AR,BohanMC Pain thresholds are elevated during pseudopregnancy.[J]Brain Res 1990;507:312-316.
[23]Dawson-Basoa M,Gintzler AR Gestational and ovarian sex steroid antinociception:synergy between spinal kappa and delta opioid systems.[J]Brain Res 1998;794:61-67.
[24]Ren K,Wei F,Dubner R,Murphy A,Hoffman GE.Progesterone attenuates persistent inflammatory hyperalgesia in female rats:involvement of spinal NMDA receptor mechanisms.[J]Brain Res 2000;865:272-7.
[25]Drury RA,Gold RM.Differential effects of ovarian hormones on reactivity to electric footshock in the rat.Physiol Behav 1978:20:187-191.
[26]Medina VM,Dawson-Basoa ME,Gintzler AR 17 beta-estradiol and progesterone positively modulate spinal cord dynorphin:relevance to the analgesia of pregnancy.[J]Neuroendocrinology 1993;58:310-315.
[27]Dawson-Basoa ME,Gintzler AR Estrogen and progesterone activate spinal kappa-opiate receptor analgesic mechanisms.[J]Pain 1996;64:608-615.
[28]Woolley CS.Estrogen-mediated structural and functional synaptic plasticity in the female rat hippocampus.[J]Horm Behav 1998:34:140-148.
[29]McEwen B.Estrogen actions throughout the brain.[J]Recent Prog Horm Res 2002;57:357-384.
[30]Cui S,Goldstein RS.Expression of estrogen receptors in the dorsal root ganglia of the chick embryo.[J]Brain Res 2000;882:236-240.
[31]Papka RE,Storey-Workley M.Estrogen receptor-alpha and-beta coexist in a subpopulation of sensory neurons of female rat dorsal root ganglia.[J]Neurosci Lett 2002;319:71-74.
[32]Bennett HL,Gustafsson JA,Keast JR.Estrogen receptor expression in lumbosacral dorsal root ganglion cells innervating the female rat urinary bladder.[J]Auton Neurosci 2003;105:90-100.
[33]Majewska MD Neurosteroids:endogenous bimodal modulators of the GABAA receptor.Mechanism of action and physiological significance.[J]Prog Neurobiol 1992;38:379-395.
[34]Paul SM,Purdy RH.Neuroactive steroids.[J]FASEB J 1992;6:2311-2322.
[35]Gu Q,Moss RL.17_-Estradiol potentiates kainate-induced currents via activation of the cAMP cascade.[J].J Neurosci 1996;16:3620-3629.
[36]Micevych PE,Eckersell CB,Brecha N,Holland KL.Estrogen modulation of opioid and cholecystokinin systems in the limbic-hypothalamic circuit.[J]Brain Res Bull 1997;44:335-343.
[37]Foy MR,Xu J,Xie X,Brinton RD,Thompson RF,Berger TW.17beta-estradiol enhances NMDA receptor-mediated EPSPs and long-term potentiation.[J].J Neurophysiol 1999;81:925-9.
[38]Rupprecht R,Holsboer F.Neuroactive steroids:mechanisms of action and neuropsychopharmacological perspectives.[J]Trends Neurosci 1999;22:410-416.
[39]Tang B,Ji Y,Traub RJ.Estrogen alters spinal NMDA receptor activity via a PKA signaling pathway in a visceral pain model in the rat.[J]Pain 2008;137:540-9.
[40]Strigo IA,Duncan GH,Catherine Bushnell M,Boivin M,Wainer I,Rodriguez Rosas ME,et al.The effects of racemic ketamine on painful stimulation of skin and viscera in human subjects.[J]Pain 2005;113:255-64.
[41]Willert R,Woolf C,Hobson A,Delaney C,Thompson D,Aziz Q. The development and maintenance of human visceral pain hypersensitivity is dependent on the N-methyl-D-aspartate receptor.[J]Gastroenterology 2004;126:683-92.
[42]Coutinho SV,Meller ST,Gebhart GF.Intracolonic zymosan produces visceral hyperalgesia in the rat that is mediated by spinal NMDA and nonNMDA receptors.[J]Brain Res 1996;736:7-15.
[43]Kolhekar R,Gebhart GF.NMDA and quisqualate modulation of visceral nociception in the rat.[J]Brain Res 1994;651:215-26.
[44]McRoberts JA,Coutinho SV,Marvizon JC,Grady EF,Tognetto M,Sengupta JN,et al.Role of peripheral N-methyl-D-aspartate (NMDA) receptors in visceral nociception in rats.[J]Gastroenterology 2001;120:1737-48.
[45]Olivar T,Laird JM.Differential effects of N-methyl-D-aspartate receptor blockade on nociceptive somatic and visceral reflexes.[J]Pain 1999;79:67-73.
[46]Zhang L,Zhang X,Westlund KN.Restoration of spontaneous exploratory behaviors with an intrathecal NMDA receptor antagonist or a PKC inhibitor in rats with acute pancreatitis.[J]Pharmacol Biochem Behav 2004;77:145-53.
[47]Gao X,Kim HK,Chung JM,Chung K.Enhancement of NMDA receptor phosphorylation of the spinal dorsal horn and nucleus gracilis neurons in neuropathic rats.[J]Pain 2005;116:62-72.
[48]Guo W,Wei F,Zou S,Robbins MT,Sugiyo S,Ikeda T,et al.Group I metabotropic glutamate receptor NMDA receptor coupling and signaling cascade mediate spinal dorsal horn NMDA receptor 2B tyrosine phosphorylation associated with inflammatory hyperalgesia.[J].J Neurosci 2004;24:9161-73.
[49]Iwata H,Takasusuki T,Yamaguchi S,Hori Y.NMDA receptor 2B subunit-mediated synaptic transmission in the superficial dorsal horn of peripheral nerve-injured neuropathic mice.[J]Brain Res 2007;1135:92- 101.
[50]Zou X,Lin Q,Willis WD.Enhanced phosphorylation of NMDA receptor 1 subunits in spinal cord dorsal horn and spinothalamic tract neurons after intradermal injection of capsaicin in rats.[J]J Neurosci 2000;20:6989-97.
[51]Zhai QZ,rraub RJ.The NMDA receptor antagonist MK-801attenuates c-Fos expression in the lumbosacral spinal cord following repetitive noxious and nonnoxious colorectal distention.[J]Pain 1999;83:321 -9.
[52]Ji Y,rraub RJ.Spinal NMDA receptors contribute to neuronal processing of acute noxious and nonnoxious colorectal stimulation in the rat.[J]J Neurophysiol 2001;86:1783-91.
[53]rraub RJ,Zhai QZ,Ji Y,Kovalenko M.NMDA receptor antagonists attenuate noxious and nonnoxious colorectal distention-induced Fos expression and the visceromotor reflex.[J]Neuroscience 2002;113:205 - 11.
[54]Al-Chaer ED,Kawasaki M,Pasricha PJ.A new model of chronic visceral hypersensitivity in adult rats induced by colon irritation during postnatal development.[J]Gastroenterology,2000;119:1276-1285.
[55]Lin C,Al-Chaer ED.Long-term sensitization of primary afferents in adult rats exposed to neonatal colon pain.[J]Brain Res.2003;971:73-82.
[56]林春,林国威,郑伟,陈爱琴,俞昌喜NMDA受体NR2B亚单位在慢性内脏痛觉敏化中的作用[J],中国药理学通报2008:24:1015-8.
[57]林国威,张睿,林春.慢性内脏痛觉敏化模型的两种行为学评价指标比较,[J]中国疼痛医学杂志,2007:13:153-156。
[58]林春,IBS样功能性慢性内脏痛的痛觉敏化作用以及离子型谷氨酸受体的作用[M],2008:72-74.
[59]姚明,杨建平,肖旺频等.大鼠结直肠扩张内脏痛模型痛阈的影响因素,[J] 中华麻醉学杂志,2004:24:554-555。
[60]肖文斌,刘玉兰,赵丽莉.性别对健康成人内脏和体表痛阈的影响,[J]中国疼痛医学杂志,2003:9:11-14。
[61]O Morteau.Experimental colitis alters visceromotor response to colorectal distension in awake rats[J].Dig Dis Sci,1994,39:1239-48.
[62]刘祥,张菊英.有序多分类重复测量资料的广义估计方程分析.[J]四川大学学报(医学版).2006,37:798-800.
[63]余松林,向惠云.重复测量资料的分析方法与SAS程序[M].北京:科学出版社,2000:183-192
[64]Arola H,TammA.Metabolism of lactose in the human body.[J]Scand J Gastroenterol,1994,29Suppl:21-25.
[65]郑建中,张岩波.有序分类重复测量数据的多水平模型分析.[J]现代预防医学2003,30:6-7
[66]Zeger SL,Liang KY,Albert PS.Mode]s for longitudinal data,a generalized estimating equation approach.[J]Biometrics,1988,44:1049-1060.
[67]Zeger SL,hiang KY.Longitudinal data analysis for discrete and continuous outcomes.[J]Biometrics,1986,42:121-130.
[68]华琳,阎岩,刘学宗.[J]药物流行病学杂志.2006,15:46-48.
[69]方积乾,孙振球.卫生统计学(5版)[M].北京.人民卫生出版社,2004:193-195.
[70]LeResche L,Saunders K,Von Korff MR,Barlow W,Dworkin SF.Use of exogenous hormones and risk of temporomandibular disorder pain.[J]Pain 1997;69:153 - 160.
[71]Dao TT,Knight K,Ton-That V.Modulation of myofascia]pain by the reproductive hormones:a preliminary report.[J]J Prosthet Dent 1998;79:663 -670.
[72]Kane SV,Sable K,Hanauer SB.The menstrual cycle and its effect on inflammatory bowel disease and irritable bowel syndrome:a prevalence study.[J]Am J Gastroenterol 1998;93:1867-1872.
[73]Dao TT,LeResche L.Gender differences in pain.[J].J Orofac Pain 2000;14:169-184.
[74]Fillingim RB,Ness TJ.Sex-related hormonal influences on pain and analgesic responses.[J]Neurosci Biobehav Rev 2000;24:485-501.
[75]Fillingim RB,Edwards RR.The association of hormone replacement therapy with experimental pain responses in postmenopausal women.[J]Pain 2001;92:229-234.
[76]Houghton LA,Lea R,Jackson N,Whorwell PJ.The menstrual cycle affects rectal sensitivity in patients with irritable bowel syndrome but not healthy volunteers.[J]Gut 2002;50:471-4.
[77]Palomba S,Orio Jr F,Manguso F,Russo T,Falbo A,Lombardi G,et al.Leuprolide acetate treatment with and without coadministration of tibolone in premenopausal women with menstrual cycle-related irritable bowel syndrome.[J]Fertil Steril 2005;83:1012-20.
[78]R.B.Fillingim,T.J.Ness.Sex-related hormonal influences on pain and analgesic responses.[J]Neuroscience and Biobehavioral Reviews 2000;24:485-501.
[79]Chakraborty TR,Gore AC.Aging-related changes in ovarian hormones,their receptors,and neuroendocrine function.[J]Exp Biol Med (Maywood) 2004;229:977-87.
[80]Knobil E,Neill JD,The physiology of reproduction[M].New York:Raven,1994:613-658.
[81]Brown-Grant K,Exley D,Naftolin F.Peripheral plasma oestradiol and luteinizing hormone concentrations during the oestrous cycle of the rat.[J].J Endocrinol 1970;48:295-296.
[82]Dupon C,Kim MH.Peripheral plasma levels of testosterone,androstenedione,and oestradiol during the rat oestrous cycle.[J].J Endocrinol1973;59:653-654.
[83]Butcher RL,Collins WE,Fugo NW.Plasma concentration of LH,FSH,prolactin,progesterone and estradiol-17beta throughout the 4-day estrous cycle of the rat.[J]Endocrinology1974;94:1704-1708.
[84]Priest CA,Vink KL,Micevych PE.Temporal regulation by estrogen of beta-preprotachykinin mRNA expression in the rat ventromedial nucleus of the hypothalamus.[J]Brain Res Mol Brain Res 1995;28:61-71.
[85]Berglund LA,Derendorf H,Simpkins JW Desensitization of brain opiate receptor mechanisms by gonadal steroid treatments that stimulate luteinizing hormone secretion.[J]Endocrinology 1988;122:2718-2726.
[86]Svensson P,Cairns BE,Wang K,Hu JW,Graven-Nielsen T,Arendt-Nielsen L,Sessle BJ.Glutamate-evoked pain and mechanical allodynia in the human masseter muscle.[J]Pain 2003;101:221-227.
[87]Cairns BE,Wang K,Hu JW,Sessle BJ,Arendt-Nielsen L,Svensson P The effect of glutamate-evoked masseter muscle pain on the human jaw-stretch reflex differs in men and women.[J]J Orofac Pain 2003:17:317 - 325.
[88]Sarlani E,Grace EG,Reynolds MA,Greenspan JD.Sex differences in temporal summation of pain and aftersensations following repetitive noxious mechanical stimulation.[J]Pain 2004;109:115- 123.
[89]Robinson ME,Wise EA,Gagnon C,Fillingim RB,Price DD.Influences of gender role and anxiety on sex differences in temporal summation of pain.[J]J Pain 2004;5:77-82.
[90]Lin C,Margaret M H.Gender Differences in Irritable Bowel Syndrome.[J]Gastroenterology,2002,123:1686-1701.
[91]张青,梁列新,钱伟等.性别及动情周期对大鼠内脏感觉影响的研究,[J]中华消化杂志,2005;25:49-50。
[92]崔楠,吴保平,吴赛珠.肠易激综合征患者外周血雌孕激素、睾酮激素含量分析,[J]现代消化及介入诊疗,2005;10:134-136。
[93]韩炜,李学会,李延青等.肠黏膜雌孕激素受体表达在肠易激综合征发病机 制中的作用研究,[J]胃肠病学和肝病学杂志,2002：11：332-334。
[94]Nemmani KV,Grisel JE,Stowe JR,Smith-Carliss R,Mogil JS.Modulation of morphine analgesia by site-specific N-methyl-Daspartate receptor antagonists:dependence on sex,site of antagonism,morphine dose,and time.[J]Pain 2004;109:274-283.
[95]LaCroix-Fralish ML,Rutkowski MD,Weinstein JN,Mogil JS,Deleo JA.The magnitude of mechanical allodynia in a rodent model of lumbar radiculopathy is dependent on strain and sex.[J]Spine 2005;30:1821-1827.
[96]Duval P,Lenoir V,Moussaoui S,Garret C,Kerdelhue B.Substance P and neurokinin A variations throughout the rat estrous cycle;comparison with ovariectomized and male rats:Ⅱ.Trigeminal nucleus and cervical spinal cord.[J].J Neurosci Res 1996;45:610-6.
[97]Kerdelhue B,Tartar A,Lenoir V,el Abed A,Hublau P,Millar RP.Binding studies of substance P anterior pituitary binding sites:changes in substance P binding sites during the rat estrous cycle.[J]Regulatory Peptides 1985;10:133-43.
[98]Smith SS.Female sex steroid hormones:from receptors to networks to performance-actions on the sensorimotor system.[J]Prog Neurobiol 1994;44:55-86.
[99]Silberstein SD,Merriam GR.Sex hormones and headache.[J].J Pain Symptom Management 1993;8:98-114.
[100]Quinones-Jenab V,Jenab S,Ogawa S,Inturrisi C,Pfaff DW.Estrogen regulation of mu-opioid receptor mRNA in the forebrain of female rats.[J]Brain Res 1997;47:134-8.
[101]Smith YR,Zubieta JK,del Carmen MG,et al.Brain opioid receptor measurements by positron emission tomography in normal cycling women:relationship to luteinizing hormone pulsatility and gonadal steroid hormones.[J].J Clin Endocrinol Metab 1998;83:4498-505.
[102]McEwen BS,Alves SE,Bulloch K,Weil NG.Clinically relevant basic science studies of gender differences and sex hormone effects.[J]Psychopharm Bull 1998;34:251-9.
[103]El Bakri NK,Islam A,Zhu S,Elhassan A,Mohammed A,Winblad B,et al.Effects of estrogen and progesterone treatment on rat hippocampal NMDA receptors:relationship to Morris water maze performance.[J].J Cell Mol Med 2004;8:537-44.
[104]Gazzaley AH,Weiland NG,McEwen BS,Morrison JH.Differential regulation of NMDAR1 mRNA and protein by estradiol in the rat hippocampus.[J].J Neurosci 1996;16:6830-8.
[105]Romeo RD,McCarthy JB,Wang A,MilnerTA,McEwen BS.Sex differences in hippocampal estradiol-induced N-methyl-D-aspartic acid binding and ultrastructural localization of estrogen receptoralpha.[J]Neuroendocrinology 2005;81:391-9.
[106]Woolley CS,Weiland NG,McEwen BS,Schwartzkroin PA.Estradiol increases the sensitivity of hippocampal CA1 pyramidal cells to NMDA receptor-mediated synaptic input:correlation with dendritic spine density.[J].J Neurosci 1997;17:1848-59.
[107]D'Souza DN,Harlan RE,Garcia MM.Modulation of glutamate receptor expression by gonadal steroid hormones in the rat striatum.[J]Brain Res Bull 2003;59:289-92.
[108]Diano S,Naftolin F,Horvath TL.Gonadal steroids target AMPA glutamate receptor-containing neurons in the rat hypothalamus,septum and amygdala:a morphological and biochemical study.[J]Endocrinology 1997;138:778-89.
[109]Kow LM,Easton A,Pfaff DW.Acute estrogen potentiates excitatory responses of neurons in rat hypothalamic ventromedial nucleus.[J]Brain Res 2005;1043:124-31.
1.Mogil JS.Interactions between sex and genotype in the mediation and modulation of nociception in rodents.In:Fillingim R,editor.Progress in pain research and management:sex,gender and pain.Seattle(WA):IASP Press;2000.p.25 - 40.
2.Holdcroft A,Sapsed-Byrne S,Ma D,Hammal D,Forsling ML.Sex and oestrous cycle differences in visceromotor responses and vasopressin release in response to colonic distension in male and female rats anaesthetized with halothane.Br J Anaesth 2000;85:907-10.
3.Giamberardino MA,Affaitati G,Valente R,Iezzi S,Vecchiet L.Changes in visceral pain reactivity as a function of estrous cycle in female rats with artificial ureteral calculosis.Brain Res 1997;774:234-8.
4.Fillingim RB,Maixner W.Gender differences in the response to noxious stimuli.Pain Forum 1995;4:209-21.
5.Holdcroft A.Females and their variability.Anaesthesia 1997:52:931-4.
6.Wesselmann U,Czakanski PP,Affaitati G,Giamberardino MA.Uterine inflammation as a noxious visceral stimulus:behavioral characterization in the rat.Neurosci Lett 1998;246:73-6.
7.Nguyen P,Lee SD,Castell DO.Evidence of gender differences in esophageal pain threshold.Am J Gastroenterol 1995;90901-5.
8.Soffer EE,Kongara K,Achkar JP,Gannon J.Colonic motor function in humans is not affected by gender.Dig Dis Sci 2000;45:1281-4.
9.Sloots CE,Felt-Bersma RJ,Cuesta MA,Meuwissen SG.Rectal visceral sensitivity in healthy volunteers:influences of gender,age and methods.Neurogastroenterol Motil 2000;12:361-8.
10.Kern MK,Jaradeh S,Arndorfer RC,Jesmanowicz A,Hyde J,Shaker R.Gender differences in cortical representation of rectal distension in healthy humans.Am J Physiol Gastrointest Liver Physiol 2001;281:G1512-23.
11.Mearadji B,Penning C,Vu MK,van der Schaar PJ,van Petersen AS,Kamerling IM,et al.Influence of gender on proximal gastric motor and sensory function.Am J Gastroenterol 2001;96:2066-73.
12.Ragnarsson G,Hallbook O,Bodemar G.Abdominal symptoms are not related to anorectal function in the irritable bowel syndrome.Scand J Gastroenterol 1999;34:250-8.
13.Berman S,Munakata J,Naliboff BD,Chang L,Mandelkern M,Silverman D,et al.Gender differences in regional brain response to visceral pressure in IBS patients.Eur J Pain 2000;4:157-72.
14.Drewes AM,Schipper KP,Dimcevski G,Petersen P,Andersen OK,Gregersen H,et al.Multimodal assessment of pain in the esophagus:a new experimental model.Am J Physiol Gastrointest Liver Physiol 2002;283:G95-G103.
15.Drewes AM,Gregersen H,Arendt-Nielsen L.Experimental pain in gastroenterology:a reappraisal of human studies.Scand J Gastroenterol 2003:38(11):1115-30.
16.Papka RE,Williams S,Miller KE,Copelin T,Puri P.CNS location of uterine-related neurons revealed by trans-synaptic tracing with pseudorabies virus and their relation to estrogen receptor-immunoreactive neurons.Neuroscience 1998;84:935-52.
17.Waliszewski P,Blaszczyk M,Wolinska-Witort E,Drews M,Snochowski M,Hurst RE.Molecular study of sex steroid receptor gene expression in human colon and in colorectal carcinomas.J Surg Oncol 1997;64:3-11.
18.Winborn WB,Sheridan PJ,McGill Jr HC.Sex steroid receptors in the stomach,liver,pancreas,and gastrointestinal tract of the baboon.Gastroenterology 1987;92:23-32.
19.Chen TS,Doong ML,Chang FY,Lee SD,Wang PS.Effects of sex steroid hormones on gastric emptying and gastrointestinal transit in rats.Am J Physiol 1995;268:G171-6.
20.Wald A,Van Thiel DH,Hoechstetter L,Gavaler JS,Egler KM,Verm R,et al.Gastrointestinal transit:the effect of the menstrual cycle.Gastroenterology 1981;80:1497-500.
21.Hinds JP,Stoney B,Wald A.Does gender or the menstrual cycle affect colonic transit.Am J Gastroenterol 1989;84:123-6.
22.Turnbull GK,Thompson DG,Day S,Martin J,Walker E,Lennard-Jones JE.Relationships between symptoms,menstrual cycle and orocaecal transit in normal and constipated women.Gut 1989;30:30-4.
23.Kamm MA,Farthing MJ,Lennard-Jones JE.Bowel function and transit rate during the menstrual cycle.Gut 1989;30:605-8.
24.Jackson NA,Houghton LA,Whorwell PJ,Currer B.Does the menstrual cycle affect anorectal physiology? Dig Dis Sci 1994;39:2607-11.
25.Arthur C,Ament ME,Song MK.Prostaglandin metabolism in relation to the bowel habits of women.Prostaglandins Leukot Essent Fatty Acids 1992;46:257-9.
26.Mathias JR,Ferguson KL,Clench MH.Debilitating functional boweldisease controlled by leuprolide acetate,gonadotropin-releasing hormone (GnRH) analog.Dig Dis Sci 1989;34:761-6.
27.Prior A,Stanley KM,Smith AR,Read NW.Relation between hysterectomy and the irritable bowel:a prospective study.Gut 1992;33:814-7.
28.Sato N,Miyake S,Akatsu J,Kumashiro M.Power spectral analysis of heart rate variability in healthy young women during the normal menstrual cycle.Psychosom Med 1995;57:331-5.
29.Bajaj Priti,Bajaj P,Madsen H,Moller M,Arendt-Nielsen L.Antenatal women with or without pelvic pain can be characterized by generalized or segmental hypoalgesia in late pregnancy.J Pain 2002;3:451-60.
30.Heitkemper MM,Jarrett M.Pattern of gastrointestinal and somatic symptoms across the menstrual cycle.Gastroenterology 1992;102:505-13.
31.Chang L,Heitkemper MM.Gender differences in irritable bowel syndrome.Gastroenterology 2002;123:1686-701.
32.Heitkemper MM,Jarrett M,Caudell KA,Bond E.Women with gastrointestinal symptoms:implications for nursing research and practice.Gastroenterol Nurs 1993;15:226-32.
33.Kane SV,Sable K,Hanauer SB.The menstrual cycle and its effect on inflammatory bowel disease and irritable bowel syndrome:a prevalence study.Am J Gastroenterol 1998;93:1867-72.
34.Fillingim RB,Maixner W,Girdler SS,Light KC,Harris MB,Sheps DS,et al.Ischemic but not thermal pain sensitivity varies across the menstrual cycle.Psychosom Med 1997;59:512-20.
35.Pfleeger M,Straneva PA,Fillingim RB,Maixner W,Girdler SS.Menstrual cycle,blood pressure and ischemic pain sensitivity in women:a preliminary investigation.Int J Psychophysiol 1997;27:161-6.
36.Bajaj P,Arendt-Nielsen L,Bajaj P,Madsen H.Sensory changes during the ovulatory phase of the menstrual cycle in healthy women.Eur J Pain 2001;5:135-46.
37.Fried GM,Ogden WD,Fagan CJ,Wiener I,Inoue K,Greeley Jr GH,et al.Comparison of cholecystokinin release and gallbladder emptying in men and in women at estrogen and progesterone phases of the menstrual cycle.Surgery 1984;95:284-9.
38.Houghton LA,Lea R,Jackson N,Whorwell PJ.The menstrual cycle affects rectal sensitivity in patients with irritable bowel syndrome but not healthy volunteers.Gut 2002;50:471-4.
39.Bajaj P,Bajaj P,Madsen H,Arendt-Nielsen L.A comparison of modality-specific somatosensory changes during menstruation in dysmenorrheic and nondysmenorrheic women.Clin J Pain 2002;18:180-90.
40.Crowell MD,Dubin NH,Robinson JC,Cheskin LJ,Schuster MM,Heller BR,et al.Functional bowel disorders in women with dysmenorrhea.Am J Gastroenterol 1994;89:1973-7.
41.Giamberardino MA,De Laurentis S,Affaitati G,Lerza R,Lapenna D,Vecchiet L.Modulation of pain and hyperalgesia from the urinary tract by algogenic conditions of the reproductive organs in women.Neurosci Lett 2001;304:61-4.
42.Lautenbacher S,Rollman GB.Possible deficiencies of pain modulation in fibromyalgia.Clin J Pain 1997;13:189-96.
43.Maixner W,Sigurdsson A,Fillingim R,Lundeen T,Booker D.Regulation of acute and chronic orofacial pain.In:Fricton JR,Dubner RB,editors.Orofacial pain and temporomandibular disorders,New York:Raven Press,1995.p.85-102.
44.Mense S.Structure-function relationships in identified afferent neurones.Anat Embryol (Berl) 1990;181:1-17.
45.Butterworth JF,Walker FO,Lysak SC.Pregnancy increases median nerve susceptibility to lidocaine.Anesthesiology 1990;72:962-5.
46.Datta S,Lambert DH,Gregus J,Gissen AJ,Covino BG.Differential sensitivities of mammalian nerve fibers during pregnancy.Anesth Analges 1983;62:1070-2.
47.Datta S,Migliozzi RP,Flanagan HL,Krieger NR.Chronically administered progesterone decreases halothane requirements in rabbits.Anesth Analges 1989;68:46-50.
48.Flanagan HL,Datta S,Lambert DH,Gissen AJ,Covino BG.Effect of pregnancy on bupivacaine-induced conduction blockade in the isolated rabbit vagus nerve.Anesth Analges 1987;66:123-6.
49.Kaneko M,Saito Y,Kirihara Y,Kosaka Y.Pregnancy enhances the antinociceptive effects of extradural lignocaine in the rat.Br J Anaesth 1994;72:657-61.
50.Robbins A,Berkley KJ,Sato Y.Estrous cycle variation of afferent fibers supplying reproductive organs in the female rat.Brain Res 1992;596:353-6.
51.Berkley KJ,Robbins A,Sato Y.Afferent fibres supplying the uterus in the rat.J Neurophysiol 1988;59:142-63.
52.Robbins A,Sato Y,Hotta H,Berkley KJ.Responses of hypogastric nerve afferent fibers to uterine distension in estrous or metestrous rats.Neurosci Lett 1990;110:82-5.
53.McMahon SB.NGF as a mediator of inflammatory pain.Phil Trans R Soc London Series B:Biol Sci 1996;351:431-40.
54.Woolf CJ.Phenotypic modification of primary sensory neurons:the role of nerve growth factor in the production of persistent pain.Phil Trans R Soc London Series B:Biol Sci 1996;351:441-8.
55.Sohrabji F,Miranda RC,Toran-Allerand CD.Estrogen differentially regulates estrogen and nerve growth factor receptor mRNAs in adult sensory neurons.J Neurosci 1994;14:459-71.
56.Zimmermann M,Herdegen T.Plasticity of the nervous system at the systemic,cellular,and molecular levels:a mechanism of chronic pain and hyperalgesia.In:Carli G,Zimmermann M,editors.Towards the neurobiology of chronic pain,Amsterdam:Elsevier,1996.p.233-59.
57.Liuzzi FJ,Scoville SA,Bufton SM.Long-term estrogen replacement coordinately decreases trkA and beta-PPT mRNA levels in dorsal root ganglion neurons.Exp Neurol 1999;155:260-7.
58.Toran-Allerand CD.Mechanisms of estrogen action during neural development:mediation by interactions with the neurotrophins and their receptors?.J Steroid Biochem Mol Biol 1996;56:Spec-78.
59.Green PG,Dahlqvist SR,Isenberg WM,Strausbaugh HJ,Miao FJ,Levine JD.Sex steroid regulation of the inflammatory response:sympathoadrenal dependence in the female rat.J Neurosci 1999;19:4082-9.
60.Duval P,Lenoir V,Moussaoui S,Garret C,Kerdelhue B.Substance P and neurokinin A variations throughout the rat estrous cycle;comparison with ovariectomized and male rats:Ⅱ.Trigeminal nucleus and cervical spinal cord.J Neurosci Res 1996;45:610-6.
61.Kerdelhue B,Tartar A,Lenoir V,el Abed A,Hublau P,Millar RP.Binding studies of substance P anterior pituitary binding sites:changes in substance P binding sites during the rat estrous cycle.Regulatory Peptides 1985;10:133-43.
62.Smith SS.Female sex steroid hormones:from receptors to networks to performance-actions on the sensorimotor system.Prog Neurobiol 1994;44:55-86.
63.Silberstein SD,Merriam GR.Sex hormones and headache.J Pain Symptom Management 1993;8:98-114.
64.Berglund LA,Simpkins JW.Alterations in brain opiate receptor mechanisms on proestrous afternoon.Neuroendocrinology 1988;48:394-400.
65.Berglund LA,Derendorf H,Simpkins JW.Desensitization of brain opiate receptor mechanisms by gonadal steroid treatments that stimulate luteinizing hormone secretion.Endocrinology 1988;122:2718-26.
66.Ratka A,Simpkins JW.A modulatory role for luteinizing hormonereleasing hormone in nociceptive responses of female rats.Endocrinology 1990;127:667-73.
67.Facchinetti F,Martignoni E,Sola D,Petraglia F,Nappi G,Genazzani AR.Transient failure of central opioid tonus and premenstrual symptoms.J Reprod Med 1988;33:633-8.
68.Quinones-Jenab V,Jenab S,Ogawa S,Inturrisi C,Pfaff DW.Estrogen regulation of mu-opioid receptor mRNA in the forebrain of female rats.Brain Res 1997;47:134-8.
69.Smith YR,Zubieta JK,del Carmen MG,et al.Brain opioid receptor measurements by positron emission tomography in normal cycling women:relationship to luteinizing hormone pulsatility and gonadal steroid hormones.J Clin Endocrinol Metab 1998;83:4498-505.
70.McEwen BS,Alves SE,Bulloch K,Weil NG.Clinically relevant basic science studies of gender differences and sex hormone effects. Psychopharm Bull 1998;34:251-9.
71.Eisenach JC,Hood DD.Sex differences in analgesia from intrathecal neostigmine in humans.Anesthesiology 1998;89:A1106.
72.Lavand' homme PM,Pan HL,Eisenach JC.Sex differences in spinal cholinergic analgesia following capsaicin.Anesthesiology 1998;89:A1170.
73.Swerdlow NR,Hartman PL,Auerbach PP.Changes in sensorimotor inhibition across the menstrual cycle:implications for neuropsychiatric disorders.Biol Psychiatry 1997;41:452-60.
74.Manber R,Bootzin RR.Sleep and the menstrual cycle.Health Psychol 1997;16:209-14.
75.Driver HS,Dijk DJ,Werth E,Biedermann K,Borbely AA.Sleep and the sleep electroencephalogram across the menstrual cycle in young healthy women.J Clin Endocrinol Metab 1996;81:728-35.
76.Backstrom T.Symptoms related to the menopause and sex steroid treatments.Ciba Foundation Symp 1995;191:171-80.
77.Klaiber EL,Broverman DM,Vogel W,Peterson LG,Snyder MB.Individual differences in changes in mood and platelet monoamine oxidase (MAO) activity during hormonal replacement therapy in menopausal women.Psychoneuroendocrinology 1996;21:575-92.
78.Priest CA,Pfaff DW.Actions of sex steroids on behaviours beyond reproductive reflexes.Ciba Foundation Symp 1995;191:74-84.
79.R.B.Fillingim,T.J.Ness.Sex-related hormonal influences on pain and analgesic responses.Neuroscience and Biobehavioral Reviews 2000;24:485-501
[2]Berkley KJ.Sex differences in pain.[J]Behav Brain Sci 1997;20:371 - 380.
[3]Mayer EA,Berman S,Chang L,Naliboff BD.Sex-based differences in gastrointestinal pain.[J]Eur J Pain 2004;8:451-63.
[4]Case AM,Reid RL.Effects of the menstrual cycle on medical disorders.[J]Arch Intern Med 1998;158:1405- 1412.
[5]Moore J,Barlow D,Jewell D,Kennedy S Do gastrointestinal symptoms vary with the menstrual cycle?[J]Br J Obstet Gynaecol 1998;105:1322 -1325.
[6]Toner BB,Akman D.Gender role and irritable bowel syndrome:literature review and hypothesis.[J]Am J Gastroenterol 2000;95:11- 16.
[7]Prior A,Stanley KM,Smith AR,Read NW.Relation between hysterectomy and the irritable bowel:a prospective study.[J]Gut 1992;33:814-817.
[8]Mathias JR,Clench MH,Reeves-Darby VG,Fox LM,Hsu PH,Roberts PH,Smith LL,Stiglich NJ.Effect of leuprolide acetate in patients with moderate to severe functional bowel disease.Double-blind,placebocontrolled study.[J]Dig Dis Sci 1994;39:1155- 1162
[9]Sapsed-Byrne S,Ma D,Ridout D,Holdcroft A.Estrous cycle phase variations in visceromotor and cardiovascular responses to colonic distension in the anesthetized rat.[J]Brain Res 1996;742:10-6.
[10]Holdcroft A,Sapsed-Byrne S,Ma D,Hammal D,Forsling ML.Sex and oestrous cycle differences in visceromotor responses and vasopressin release in response to colonic distention in male and female rats anesthetized with halothane.[J]Br J Anaesth 2000;85:907-910
[11]Robbins A,Berkley KJ,Sato Y.Estrous cycle variation of afferent fibers supplying reproductive organs in the female rat.[J]Brain Res 1992;596:353-6.
[12]Bradshaw HB,Temple JL,Wood E,Berkley KJ.Estrous variations in behavioral responses to vaginal and uterine distention in the rat.[J]Pain 1999;82:187-97.
[13]Forman LJ,Tingle V,Estilow S,Cater J.The response to analgesia testing is affected by gonadal steroids in the rat.[J]Life Sci 1989;45:447-454.
[14]Ratka A,Simpkins JW.Effects of estradiol and progesterone on the sensitivity to pain and on morphine-induced antinociception in female rats.[J]Horm Behav 1991;25:217-228.
[15]Kayser V,Berkley KJ,Keita H,Gautron M,Guilbaud G.Estrous and sex variations in vocalization thresholds to hindpaw and tail pressure stimulation in the rat.[J]Brain Res 1996;742:352-354.
[16]Bradshaw H,Miller J,Ling QD,Malsnee K,RudaMA.Sex differences and phases of the estrous cycle alter the response of spinal cord dynorphin neurons to peripheral inflammation and hyperalgesia.[J]Pain 2000;85:93-99.
[17]Bereiter DA.Sex differences in brainstem neural activation after injury to the TMJ region.[J]Cells Tissues Organs 2001;169:226-237.
[18]Ji Y,Murphy AZ,Traub RJ.Estrogen modulates the visceromotor reflex and responses of spinal dorsal horn neurons to colorectal stimulation in the rat.[J].J Neurosci 2003;23:3908-15.
[19]Ji Y,Tang B,Traub RJ.Modulatory effects of estrogen and progesterone on colorectal hyperalgesia in the rat.[J]Pain 2005;117:433-442.
[20]Martinez-Gomez M,Cruz Y,Salas M,Hudson R,Pacheco P Assessing pain threshold in the rat:changes with estrus and time of day.[J]Physiol Behav 1994;55:651-657.
[21]Giamberardino MA,Affaitati G,Valente R,Iezzi S,Vecchiet L Changes in visceral pain reactivity as a function of estrous cycle in female rats with artificial ureteral calculosis.[J]Brain Res 1997;774:234-238.
[22]Gintzler AR,BohanMC Pain thresholds are elevated during pseudopregnancy.[J]Brain Res 1990;507:312-316.
[23]Dawson-Basoa M,Gintzler AR Gestational and ovarian sex steroid antinociception:synergy between spinal kappa and delta opioid systems.[J]Brain Res 1998;794:61-67.
[24]Ren K,Wei F,Dubner R,Murphy A,Hoffman GE.Progesterone attenuates persistent inflammatory hyperalgesia in female rats:involvement of spinal NMDA receptor mechanisms.[J]Brain Res 2000;865:272-7.
[25]Drury RA,Gold RM.Differential effects of ovarian hormones on reactivity to electric footshock in the rat.Physiol Behav 1978:20:187-191.
[26]Medina VM,Dawson-Basoa ME,Gintzler AR 17 beta-estradiol and progesterone positively modulate spinal cord dynorphin:relevance to the analgesia of pregnancy.[J]Neuroendocrinology 1993;58:310-315.
[27]Dawson-Basoa ME,Gintzler AR Estrogen and progesterone activate spinal kappa-opiate receptor analgesic mechanisms.[J]Pain 1996;64:608-615.
[28]Woolley CS.Estrogen-mediated structural and functional synaptic plasticity in the female rat hippocampus.[J]Horm Behav 1998:34:140-148.
[29]McEwen B.Estrogen actions throughout the brain.[J]Recent Prog Horm Res 2002;57:357-384.
[30]Cui S,Goldstein RS.Expression of estrogen receptors in the dorsal root ganglia of the chick embryo.[J]Brain Res 2000;882:236-240.
[31]Papka RE,Storey-Workley M.Estrogen receptor-alpha and-beta coexist in a subpopulation of sensory neurons of female rat dorsal root ganglia.[J]Neurosci Lett 2002;319:71-74.
[32]Bennett HL,Gustafsson JA,Keast JR.Estrogen receptor expression in lumbosacral dorsal root ganglion cells innervating the female rat urinary bladder.[J]Auton Neurosci 2003;105:90-100.
[33]Majewska MD Neurosteroids:endogenous bimodal modulators of the GABAA receptor.Mechanism of action and physiological significance.[J]Prog Neurobiol 1992;38:379-395.
[34]Paul SM,Purdy RH.Neuroactive steroids.[J]FASEB J 1992;6:2311-2322.
[35]Gu Q,Moss RL.17_-Estradiol potentiates kainate-induced currents via activation of the cAMP cascade.[J].J Neurosci 1996;16:3620-3629.
[36]Micevych PE,Eckersell CB,Brecha N,Holland KL.Estrogen modulation of opioid and cholecystokinin systems in the limbic-hypothalamic circuit.[J]Brain Res Bull 1997;44:335-343.
[37]Foy MR,Xu J,Xie X,Brinton RD,Thompson RF,Berger TW.17beta-estradiol enhances NMDA receptor-mediated EPSPs and long-term potentiation.[J].J Neurophysiol 1999;81:925-9.
[38]Rupprecht R,Holsboer F.Neuroactive steroids:mechanisms of action and neuropsychopharmacological perspectives.[J]Trends Neurosci 1999;22:410-416.
[39]Tang B,Ji Y,Traub RJ.Estrogen alters spinal NMDA receptor activity via a PKA signaling pathway in a visceral pain model in the rat.[J]Pain 2008;137:540-9.
[40]Strigo IA,Duncan GH,Catherine Bushnell M,Boivin M,Wainer I,Rodriguez Rosas ME,et al.The effects of racemic ketamine on painful stimulation of skin and viscera in human subjects.[J]Pain 2005;113:255-64.
[41]Willert R,Woolf C,Hobson A,Delaney C,Thompson D,Aziz Q. The development and maintenance of human visceral pain hypersensitivity is dependent on the N-methyl-D-aspartate receptor.[J]Gastroenterology 2004;126:683-92.
[42]Coutinho SV,Meller ST,Gebhart GF.Intracolonic zymosan produces visceral hyperalgesia in the rat that is mediated by spinal NMDA and nonNMDA receptors.[J]Brain Res 1996;736:7-15.
[43]Kolhekar R,Gebhart GF.NMDA and quisqualate modulation of visceral nociception in the rat.[J]Brain Res 1994;651:215-26.
[44]McRoberts JA,Coutinho SV,Marvizon JC,Grady EF,Tognetto M,Sengupta JN,et al.Role of peripheral N-methyl-D-aspartate (NMDA) receptors in visceral nociception in rats.[J]Gastroenterology 2001;120:1737-48.
[45]Olivar T,Laird JM.Differential effects of N-methyl-D-aspartate receptor blockade on nociceptive somatic and visceral reflexes.[J]Pain 1999;79:67-73.
[46]Zhang L,Zhang X,Westlund KN.Restoration of spontaneous exploratory behaviors with an intrathecal NMDA receptor antagonist or a PKC inhibitor in rats with acute pancreatitis.[J]Pharmacol Biochem Behav 2004;77:145-53.
[47]Gao X,Kim HK,Chung JM,Chung K.Enhancement of NMDA receptor phosphorylation of the spinal dorsal horn and nucleus gracilis neurons in neuropathic rats.[J]Pain 2005;116:62-72.
[48]Guo W,Wei F,Zou S,Robbins MT,Sugiyo S,Ikeda T,et al.Group I metabotropic glutamate receptor NMDA receptor coupling and signaling cascade mediate spinal dorsal horn NMDA receptor 2B tyrosine phosphorylation associated with inflammatory hyperalgesia.[J].J Neurosci 2004;24:9161-73.
[49]Iwata H,Takasusuki T,Yamaguchi S,Hori Y.NMDA receptor 2B subunit-mediated synaptic transmission in the superficial dorsal horn of peripheral nerve-injured neuropathic mice.[J]Brain Res 2007;1135:92- 101.
[50]Zou X,Lin Q,Willis WD.Enhanced phosphorylation of NMDA receptor 1 subunits in spinal cord dorsal horn and spinothalamic tract neurons after intradermal injection of capsaicin in rats.[J]J Neurosci 2000;20:6989-97.
[51]Zhai QZ,rraub RJ.The NMDA receptor antagonist MK-801attenuates c-Fos expression in the lumbosacral spinal cord following repetitive noxious and nonnoxious colorectal distention.[J]Pain 1999;83:321 -9.
[52]Ji Y,rraub RJ.Spinal NMDA receptors contribute to neuronal processing of acute noxious and nonnoxious colorectal stimulation in the rat.[J]J Neurophysiol 2001;86:1783-91.
[53]rraub RJ,Zhai QZ,Ji Y,Kovalenko M.NMDA receptor antagonists attenuate noxious and nonnoxious colorectal distention-induced Fos expression and the visceromotor reflex.[J]Neuroscience 2002;113:205 - 11.
[54]Al-Chaer ED,Kawasaki M,Pasricha PJ.A new model of chronic visceral hypersensitivity in adult rats induced by colon irritation during postnatal development.[J]Gastroenterology,2000;119:1276-1285.
[55]Lin C,Al-Chaer ED.Long-term sensitization of primary afferents in adult rats exposed to neonatal colon pain.[J]Brain Res.2003;971:73-82.
[56]林春,林国威,郑伟,陈爱琴,俞昌喜NMDA受体NR2B亚单位在慢性内脏痛觉敏化中的作用[J],中国药理学通报2008:24:1015-8.
[57]林国威,张睿,林春.慢性内脏痛觉敏化模型的两种行为学评价指标比较,[J]中国疼痛医学杂志,2007:13:153-156。
[58]林春,IBS样功能性慢性内脏痛的痛觉敏化作用以及离子型谷氨酸受体的作用[M],2008:72-74.
[59]姚明,杨建平,肖旺频等.大鼠结直肠扩张内脏痛模型痛阈的影响因素,[J] 中华麻醉学杂志,2004:24:554-555。
[60]肖文斌,刘玉兰,赵丽莉.性别对健康成人内脏和体表痛阈的影响,[J]中国疼痛医学杂志,2003:9:11-14。
[61]O Morteau.Experimental colitis alters visceromotor response to colorectal distension in awake rats[J].Dig Dis Sci,1994,39:1239-48.
[62]刘祥,张菊英.有序多分类重复测量资料的广义估计方程分析.[J]四川大学学报(医学版).2006,37:798-800.
[63]余松林,向惠云.重复测量资料的分析方法与SAS程序[M].北京:科学出版社,2000:183-192
[64]Arola H,TammA.Metabolism of lactose in the human body.[J]Scand J Gastroenterol,1994,29Suppl:21-25.
[65]郑建中,张岩波.有序分类重复测量数据的多水平模型分析.[J]现代预防医学2003,30:6-7
[66]Zeger SL,Liang KY,Albert PS.Mode]s for longitudinal data,a generalized estimating equation approach.[J]Biometrics,1988,44:1049-1060.
[67]Zeger SL,hiang KY.Longitudinal data analysis for discrete and continuous outcomes.[J]Biometrics,1986,42:121-130.
[68]华琳,阎岩,刘学宗.[J]药物流行病学杂志.2006,15:46-48.
[69]方积乾,孙振球.卫生统计学(5版)[M].北京.人民卫生出版社,2004:193-195.
[70]LeResche L,Saunders K,Von Korff MR,Barlow W,Dworkin SF.Use of exogenous hormones and risk of temporomandibular disorder pain.[J]Pain 1997;69:153 - 160.
[71]Dao TT,Knight K,Ton-That V.Modulation of myofascia]pain by the reproductive hormones:a preliminary report.[J]J Prosthet Dent 1998;79:663 -670.
[72]Kane SV,Sable K,Hanauer SB.The menstrual cycle and its effect on inflammatory bowel disease and irritable bowel syndrome:a prevalence study.[J]Am J Gastroenterol 1998;93:1867-1872.
[73]Dao TT,LeResche L.Gender differences in pain.[J].J Orofac Pain 2000;14:169-184.
[74]Fillingim RB,Ness TJ.Sex-related hormonal influences on pain and analgesic responses.[J]Neurosci Biobehav Rev 2000;24:485-501.
[75]Fillingim RB,Edwards RR.The association of hormone replacement therapy with experimental pain responses in postmenopausal women.[J]Pain 2001;92:229-234.
[76]Houghton LA,Lea R,Jackson N,Whorwell PJ.The menstrual cycle affects rectal sensitivity in patients with irritable bowel syndrome but not healthy volunteers.[J]Gut 2002;50:471-4.
[77]Palomba S,Orio Jr F,Manguso F,Russo T,Falbo A,Lombardi G,et al.Leuprolide acetate treatment with and without coadministration of tibolone in premenopausal women with menstrual cycle-related irritable bowel syndrome.[J]Fertil Steril 2005;83:1012-20.
[78]R.B.Fillingim,T.J.Ness.Sex-related hormonal influences on pain and analgesic responses.[J]Neuroscience and Biobehavioral Reviews 2000;24:485-501.
[79]Chakraborty TR,Gore AC.Aging-related changes in ovarian hormones,their receptors,and neuroendocrine function.[J]Exp Biol Med (Maywood) 2004;229:977-87.
[80]Knobil E,Neill JD,The physiology of reproduction[M].New York:Raven,1994:613-658.
[81]Brown-Grant K,Exley D,Naftolin F.Peripheral plasma oestradiol and luteinizing hormone concentrations during the oestrous cycle of the rat.[J].J Endocrinol 1970;48:295-296.
[82]Dupon C,Kim MH.Peripheral plasma levels of testosterone,androstenedione,and oestradiol during the rat oestrous cycle.[J].J Endocrinol1973;59:653-654.
[83]Butcher RL,Collins WE,Fugo NW.Plasma concentration of LH,FSH,prolactin,progesterone and estradiol-17beta throughout the 4-day estrous cycle of the rat.[J]Endocrinology1974;94:1704-1708.
[84]Priest CA,Vink KL,Micevych PE.Temporal regulation by estrogen of beta-preprotachykinin mRNA expression in the rat ventromedial nucleus of the hypothalamus.[J]Brain Res Mol Brain Res 1995;28:61-71.
[85]Berglund LA,Derendorf H,Simpkins JW Desensitization of brain opiate receptor mechanisms by gonadal steroid treatments that stimulate luteinizing hormone secretion.[J]Endocrinology 1988;122:2718-2726.
[86]Svensson P,Cairns BE,Wang K,Hu JW,Graven-Nielsen T,Arendt-Nielsen L,Sessle BJ.Glutamate-evoked pain and mechanical allodynia in the human masseter muscle.[J]Pain 2003;101:221-227.
[87]Cairns BE,Wang K,Hu JW,Sessle BJ,Arendt-Nielsen L,Svensson P The effect of glutamate-evoked masseter muscle pain on the human jaw-stretch reflex differs in men and women.[J]J Orofac Pain 2003:17:317 - 325.
[88]Sarlani E,Grace EG,Reynolds MA,Greenspan JD.Sex differences in temporal summation of pain and aftersensations following repetitive noxious mechanical stimulation.[J]Pain 2004;109:115- 123.
[89]Robinson ME,Wise EA,Gagnon C,Fillingim RB,Price DD.Influences of gender role and anxiety on sex differences in temporal summation of pain.[J]J Pain 2004;5:77-82.
[90]Lin C,Margaret M H.Gender Differences in Irritable Bowel Syndrome.[J]Gastroenterology,2002,123:1686-1701.
[91]张青,梁列新,钱伟等.性别及动情周期对大鼠内脏感觉影响的研究,[J]中华消化杂志,2005;25:49-50。
[92]崔楠,吴保平,吴赛珠.肠易激综合征患者外周血雌孕激素、睾酮激素含量分析,[J]现代消化及介入诊疗,2005;10:134-136。
[93]韩炜,李学会,李延青等.肠黏膜雌孕激素受体表达在肠易激综合征发病机 制中的作用研究,[J]胃肠病学和肝病学杂志,2002：11：332-334。
[94]Nemmani KV,Grisel JE,Stowe JR,Smith-Carliss R,Mogil JS.Modulation of morphine analgesia by site-specific N-methyl-Daspartate receptor antagonists:dependence on sex,site of antagonism,morphine dose,and time.[J]Pain 2004;109:274-283.
[95]LaCroix-Fralish ML,Rutkowski MD,Weinstein JN,Mogil JS,Deleo JA.The magnitude of mechanical allodynia in a rodent model of lumbar radiculopathy is dependent on strain and sex.[J]Spine 2005;30:1821-1827.
[96]Duval P,Lenoir V,Moussaoui S,Garret C,Kerdelhue B.Substance P and neurokinin A variations throughout the rat estrous cycle;comparison with ovariectomized and male rats:Ⅱ.Trigeminal nucleus and cervical spinal cord.[J].J Neurosci Res 1996;45:610-6.
[97]Kerdelhue B,Tartar A,Lenoir V,el Abed A,Hublau P,Millar RP.Binding studies of substance P anterior pituitary binding sites:changes in substance P binding sites during the rat estrous cycle.[J]Regulatory Peptides 1985;10:133-43.
[98]Smith SS.Female sex steroid hormones:from receptors to networks to performance-actions on the sensorimotor system.[J]Prog Neurobiol 1994;44:55-86.
[99]Silberstein SD,Merriam GR.Sex hormones and headache.[J].J Pain Symptom Management 1993;8:98-114.
[100]Quinones-Jenab V,Jenab S,Ogawa S,Inturrisi C,Pfaff DW.Estrogen regulation of mu-opioid receptor mRNA in the forebrain of female rats.[J]Brain Res 1997;47:134-8.
[101]Smith YR,Zubieta JK,del Carmen MG,et al.Brain opioid receptor measurements by positron emission tomography in normal cycling women:relationship to luteinizing hormone pulsatility and gonadal steroid hormones.[J].J Clin Endocrinol Metab 1998;83:4498-505.
[102]McEwen BS,Alves SE,Bulloch K,Weil NG.Clinically relevant basic science studies of gender differences and sex hormone effects.[J]Psychopharm Bull 1998;34:251-9.
[103]El Bakri NK,Islam A,Zhu S,Elhassan A,Mohammed A,Winblad B,et al.Effects of estrogen and progesterone treatment on rat hippocampal NMDA receptors:relationship to Morris water maze performance.[J].J Cell Mol Med 2004;8:537-44.
[104]Gazzaley AH,Weiland NG,McEwen BS,Morrison JH.Differential regulation of NMDAR1 mRNA and protein by estradiol in the rat hippocampus.[J].J Neurosci 1996;16:6830-8.
[105]Romeo RD,McCarthy JB,Wang A,MilnerTA,McEwen BS.Sex differences in hippocampal estradiol-induced N-methyl-D-aspartic acid binding and ultrastructural localization of estrogen receptoralpha.[J]Neuroendocrinology 2005;81:391-9.
[106]Woolley CS,Weiland NG,McEwen BS,Schwartzkroin PA.Estradiol increases the sensitivity of hippocampal CA1 pyramidal cells to NMDA receptor-mediated synaptic input:correlation with dendritic spine density.[J].J Neurosci 1997;17:1848-59.
[107]D'Souza DN,Harlan RE,Garcia MM.Modulation of glutamate receptor expression by gonadal steroid hormones in the rat striatum.[J]Brain Res Bull 2003;59:289-92.
[108]Diano S,Naftolin F,Horvath TL.Gonadal steroids target AMPA glutamate receptor-containing neurons in the rat hypothalamus,septum and amygdala:a morphological and biochemical study.[J]Endocrinology 1997;138:778-89.
[109]Kow LM,Easton A,Pfaff DW.Acute estrogen potentiates excitatory responses of neurons in rat hypothalamic ventromedial nucleus.[J]Brain Res 2005;1043:124-31.
1.Mogil JS.Interactions between sex and genotype in the mediation and modulation of nociception in rodents.In:Fillingim R,editor.Progress in pain research and management:sex,gender and pain.Seattle(WA):IASP Press;2000.p.25 - 40.
2.Holdcroft A,Sapsed-Byrne S,Ma D,Hammal D,Forsling ML.Sex and oestrous cycle differences in visceromotor responses and vasopressin release in response to colonic distension in male and female rats anaesthetized with halothane.Br J Anaesth 2000;85:907-10.
3.Giamberardino MA,Affaitati G,Valente R,Iezzi S,Vecchiet L.Changes in visceral pain reactivity as a function of estrous cycle in female rats with artificial ureteral calculosis.Brain Res 1997;774:234-8.
4.Fillingim RB,Maixner W.Gender differences in the response to noxious stimuli.Pain Forum 1995;4:209-21.
5.Holdcroft A.Females and their variability.Anaesthesia 1997:52:931-4.
6.Wesselmann U,Czakanski PP,Affaitati G,Giamberardino MA.Uterine inflammation as a noxious visceral stimulus:behavioral characterization in the rat.Neurosci Lett 1998;246:73-6.
7.Nguyen P,Lee SD,Castell DO.Evidence of gender differences in esophageal pain threshold.Am J Gastroenterol 1995;90901-5.
8.Soffer EE,Kongara K,Achkar JP,Gannon J.Colonic motor function in humans is not affected by gender.Dig Dis Sci 2000;45:1281-4.
9.Sloots CE,Felt-Bersma RJ,Cuesta MA,Meuwissen SG.Rectal visceral sensitivity in healthy volunteers:influences of gender,age and methods.Neurogastroenterol Motil 2000;12:361-8.
10.Kern MK,Jaradeh S,Arndorfer RC,Jesmanowicz A,Hyde J,Shaker R.Gender differences in cortical representation of rectal distension in healthy humans.Am J Physiol Gastrointest Liver Physiol 2001;281:G1512-23.
11.Mearadji B,Penning C,Vu MK,van der Schaar PJ,van Petersen AS,Kamerling IM,et al.Influence of gender on proximal gastric motor and sensory function.Am J Gastroenterol 2001;96:2066-73.
12.Ragnarsson G,Hallbook O,Bodemar G.Abdominal symptoms are not related to anorectal function in the irritable bowel syndrome.Scand J Gastroenterol 1999;34:250-8.
13.Berman S,Munakata J,Naliboff BD,Chang L,Mandelkern M,Silverman D,et al.Gender differences in regional brain response to visceral pressure in IBS patients.Eur J Pain 2000;4:157-72.
14.Drewes AM,Schipper KP,Dimcevski G,Petersen P,Andersen OK,Gregersen H,et al.Multimodal assessment of pain in the esophagus:a new experimental model.Am J Physiol Gastrointest Liver Physiol 2002;283:G95-G103.
15.Drewes AM,Gregersen H,Arendt-Nielsen L.Experimental pain in gastroenterology:a reappraisal of human studies.Scand J Gastroenterol 2003:38(11):1115-30.
16.Papka RE,Williams S,Miller KE,Copelin T,Puri P.CNS location of uterine-related neurons revealed by trans-synaptic tracing with pseudorabies virus and their relation to estrogen receptor-immunoreactive neurons.Neuroscience 1998;84:935-52.
17.Waliszewski P,Blaszczyk M,Wolinska-Witort E,Drews M,Snochowski M,Hurst RE.Molecular study of sex steroid receptor gene expression in human colon and in colorectal carcinomas.J Surg Oncol 1997;64:3-11.
18.Winborn WB,Sheridan PJ,McGill Jr HC.Sex steroid receptors in the stomach,liver,pancreas,and gastrointestinal tract of the baboon.Gastroenterology 1987;92:23-32.
19.Chen TS,Doong ML,Chang FY,Lee SD,Wang PS.Effects of sex steroid hormones on gastric emptying and gastrointestinal transit in rats.Am J Physiol 1995;268:G171-6.
20.Wald A,Van Thiel DH,Hoechstetter L,Gavaler JS,Egler KM,Verm R,et al.Gastrointestinal transit:the effect of the menstrual cycle.Gastroenterology 1981;80:1497-500.
21.Hinds JP,Stoney B,Wald A.Does gender or the menstrual cycle affect colonic transit.Am J Gastroenterol 1989;84:123-6.
22.Turnbull GK,Thompson DG,Day S,Martin J,Walker E,Lennard-Jones JE.Relationships between symptoms,menstrual cycle and orocaecal transit in normal and constipated women.Gut 1989;30:30-4.
23.Kamm MA,Farthing MJ,Lennard-Jones JE.Bowel function and transit rate during the menstrual cycle.Gut 1989;30:605-8.
24.Jackson NA,Houghton LA,Whorwell PJ,Currer B.Does the menstrual cycle affect anorectal physiology? Dig Dis Sci 1994;39:2607-11.
25.Arthur C,Ament ME,Song MK.Prostaglandin metabolism in relation to the bowel habits of women.Prostaglandins Leukot Essent Fatty Acids 1992;46:257-9.
26.Mathias JR,Ferguson KL,Clench MH.Debilitating functional boweldisease controlled by leuprolide acetate,gonadotropin-releasing hormone (GnRH) analog.Dig Dis Sci 1989;34:761-6.
27.Prior A,Stanley KM,Smith AR,Read NW.Relation between hysterectomy and the irritable bowel:a prospective study.Gut 1992;33:814-7.
28.Sato N,Miyake S,Akatsu J,Kumashiro M.Power spectral analysis of heart rate variability in healthy young women during the normal menstrual cycle.Psychosom Med 1995;57:331-5.
29.Bajaj Priti,Bajaj P,Madsen H,Moller M,Arendt-Nielsen L.Antenatal women with or without pelvic pain can be characterized by generalized or segmental hypoalgesia in late pregnancy.J Pain 2002;3:451-60.
30.Heitkemper MM,Jarrett M.Pattern of gastrointestinal and somatic symptoms across the menstrual cycle.Gastroenterology 1992;102:505-13.
31.Chang L,Heitkemper MM.Gender differences in irritable bowel syndrome.Gastroenterology 2002;123:1686-701.
32.Heitkemper MM,Jarrett M,Caudell KA,Bond E.Women with gastrointestinal symptoms:implications for nursing research and practice.Gastroenterol Nurs 1993;15:226-32.
33.Kane SV,Sable K,Hanauer SB.The menstrual cycle and its effect on inflammatory bowel disease and irritable bowel syndrome:a prevalence study.Am J Gastroenterol 1998;93:1867-72.
34.Fillingim RB,Maixner W,Girdler SS,Light KC,Harris MB,Sheps DS,et al.Ischemic but not thermal pain sensitivity varies across the menstrual cycle.Psychosom Med 1997;59:512-20.
35.Pfleeger M,Straneva PA,Fillingim RB,Maixner W,Girdler SS.Menstrual cycle,blood pressure and ischemic pain sensitivity in women:a preliminary investigation.Int J Psychophysiol 1997;27:161-6.
36.Bajaj P,Arendt-Nielsen L,Bajaj P,Madsen H.Sensory changes during the ovulatory phase of the menstrual cycle in healthy women.Eur J Pain 2001;5:135-46.
37.Fried GM,Ogden WD,Fagan CJ,Wiener I,Inoue K,Greeley Jr GH,et al.Comparison of cholecystokinin release and gallbladder emptying in men and in women at estrogen and progesterone phases of the menstrual cycle.Surgery 1984;95:284-9.
38.Houghton LA,Lea R,Jackson N,Whorwell PJ.The menstrual cycle affects rectal sensitivity in patients with irritable bowel syndrome but not healthy volunteers.Gut 2002;50:471-4.
39.Bajaj P,Bajaj P,Madsen H,Arendt-Nielsen L.A comparison of modality-specific somatosensory changes during menstruation in dysmenorrheic and nondysmenorrheic women.Clin J Pain 2002;18:180-90.
40.Crowell MD,Dubin NH,Robinson JC,Cheskin LJ,Schuster MM,Heller BR,et al.Functional bowel disorders in women with dysmenorrhea.Am J Gastroenterol 1994;89:1973-7.
41.Giamberardino MA,De Laurentis S,Affaitati G,Lerza R,Lapenna D,Vecchiet L.Modulation of pain and hyperalgesia from the urinary tract by algogenic conditions of the reproductive organs in women.Neurosci Lett 2001;304:61-4.
42.Lautenbacher S,Rollman GB.Possible deficiencies of pain modulation in fibromyalgia.Clin J Pain 1997;13:189-96.
43.Maixner W,Sigurdsson A,Fillingim R,Lundeen T,Booker D.Regulation of acute and chronic orofacial pain.In:Fricton JR,Dubner RB,editors.Orofacial pain and temporomandibular disorders,New York:Raven Press,1995.p.85-102.
44.Mense S.Structure-function relationships in identified afferent neurones.Anat Embryol (Berl) 1990;181:1-17.
45.Butterworth JF,Walker FO,Lysak SC.Pregnancy increases median nerve susceptibility to lidocaine.Anesthesiology 1990;72:962-5.
46.Datta S,Lambert DH,Gregus J,Gissen AJ,Covino BG.Differential sensitivities of mammalian nerve fibers during pregnancy.Anesth Analges 1983;62:1070-2.
47.Datta S,Migliozzi RP,Flanagan HL,Krieger NR.Chronically administered progesterone decreases halothane requirements in rabbits.Anesth Analges 1989;68:46-50.
48.Flanagan HL,Datta S,Lambert DH,Gissen AJ,Covino BG.Effect of pregnancy on bupivacaine-induced conduction blockade in the isolated rabbit vagus nerve.Anesth Analges 1987;66:123-6.
49.Kaneko M,Saito Y,Kirihara Y,Kosaka Y.Pregnancy enhances the antinociceptive effects of extradural lignocaine in the rat.Br J Anaesth 1994;72:657-61.
50.Robbins A,Berkley KJ,Sato Y.Estrous cycle variation of afferent fibers supplying reproductive organs in the female rat.Brain Res 1992;596:353-6.
51.Berkley KJ,Robbins A,Sato Y.Afferent fibres supplying the uterus in the rat.J Neurophysiol 1988;59:142-63.
52.Robbins A,Sato Y,Hotta H,Berkley KJ.Responses of hypogastric nerve afferent fibers to uterine distension in estrous or metestrous rats.Neurosci Lett 1990;110:82-5.
53.McMahon SB.NGF as a mediator of inflammatory pain.Phil Trans R Soc London Series B:Biol Sci 1996;351:431-40.
54.Woolf CJ.Phenotypic modification of primary sensory neurons:the role of nerve growth factor in the production of persistent pain.Phil Trans R Soc London Series B:Biol Sci 1996;351:441-8.
55.Sohrabji F,Miranda RC,Toran-Allerand CD.Estrogen differentially regulates estrogen and nerve growth factor receptor mRNAs in adult sensory neurons.J Neurosci 1994;14:459-71.
56.Zimmermann M,Herdegen T.Plasticity of the nervous system at the systemic,cellular,and molecular levels:a mechanism of chronic pain and hyperalgesia.In:Carli G,Zimmermann M,editors.Towards the neurobiology of chronic pain,Amsterdam:Elsevier,1996.p.233-59.
57.Liuzzi FJ,Scoville SA,Bufton SM.Long-term estrogen replacement coordinately decreases trkA and beta-PPT mRNA levels in dorsal root ganglion neurons.Exp Neurol 1999;155:260-7.
58.Toran-Allerand CD.Mechanisms of estrogen action during neural development:mediation by interactions with the neurotrophins and their receptors?.J Steroid Biochem Mol Biol 1996;56:Spec-78.
59.Green PG,Dahlqvist SR,Isenberg WM,Strausbaugh HJ,Miao FJ,Levine JD.Sex steroid regulation of the inflammatory response:sympathoadrenal dependence in the female rat.J Neurosci 1999;19:4082-9.
60.Duval P,Lenoir V,Moussaoui S,Garret C,Kerdelhue B.Substance P and neurokinin A variations throughout the rat estrous cycle;comparison with ovariectomized and male rats:Ⅱ.Trigeminal nucleus and cervical spinal cord.J Neurosci Res 1996;45:610-6.
61.Kerdelhue B,Tartar A,Lenoir V,el Abed A,Hublau P,Millar RP.Binding studies of substance P anterior pituitary binding sites:changes in substance P binding sites during the rat estrous cycle.Regulatory Peptides 1985;10:133-43.
62.Smith SS.Female sex steroid hormones:from receptors to networks to performance-actions on the sensorimotor system.Prog Neurobiol 1994;44:55-86.
63.Silberstein SD,Merriam GR.Sex hormones and headache.J Pain Symptom Management 1993;8:98-114.
64.Berglund LA,Simpkins JW.Alterations in brain opiate receptor mechanisms on proestrous afternoon.Neuroendocrinology 1988;48:394-400.
65.Berglund LA,Derendorf H,Simpkins JW.Desensitization of brain opiate receptor mechanisms by gonadal steroid treatments that stimulate luteinizing hormone secretion.Endocrinology 1988;122:2718-26.
66.Ratka A,Simpkins JW.A modulatory role for luteinizing hormonereleasing hormone in nociceptive responses of female rats.Endocrinology 1990;127:667-73.
67.Facchinetti F,Martignoni E,Sola D,Petraglia F,Nappi G,Genazzani AR.Transient failure of central opioid tonus and premenstrual symptoms.J Reprod Med 1988;33:633-8.
68.Quinones-Jenab V,Jenab S,Ogawa S,Inturrisi C,Pfaff DW.Estrogen regulation of mu-opioid receptor mRNA in the forebrain of female rats.Brain Res 1997;47:134-8.
69.Smith YR,Zubieta JK,del Carmen MG,et al.Brain opioid receptor measurements by positron emission tomography in normal cycling women:relationship to luteinizing hormone pulsatility and gonadal steroid hormones.J Clin Endocrinol Metab 1998;83:4498-505.
70.McEwen BS,Alves SE,Bulloch K,Weil NG.Clinically relevant basic science studies of gender differences and sex hormone effects. Psychopharm Bull 1998;34:251-9.
71.Eisenach JC,Hood DD.Sex differences in analgesia from intrathecal neostigmine in humans.Anesthesiology 1998;89:A1106.
72.Lavand' homme PM,Pan HL,Eisenach JC.Sex differences in spinal cholinergic analgesia following capsaicin.Anesthesiology 1998;89:A1170.
73.Swerdlow NR,Hartman PL,Auerbach PP.Changes in sensorimotor inhibition across the menstrual cycle:implications for neuropsychiatric disorders.Biol Psychiatry 1997;41:452-60.
74.Manber R,Bootzin RR.Sleep and the menstrual cycle.Health Psychol 1997;16:209-14.
75.Driver HS,Dijk DJ,Werth E,Biedermann K,Borbely AA.Sleep and the sleep electroencephalogram across the menstrual cycle in young healthy women.J Clin Endocrinol Metab 1996;81:728-35.
76.Backstrom T.Symptoms related to the menopause and sex steroid treatments.Ciba Foundation Symp 1995;191:171-80.
77.Klaiber EL,Broverman DM,Vogel W,Peterson LG,Snyder MB.Individual differences in changes in mood and platelet monoamine oxidase (MAO) activity during hormonal replacement therapy in menopausal women.Psychoneuroendocrinology 1996;21:575-92.
78.Priest CA,Pfaff DW.Actions of sex steroids on behaviours beyond reproductive reflexes.Ciba Foundation Symp 1995;191:74-84.
79.R.B.Fillingim,T.J.Ness.Sex-related hormonal influences on pain and analgesic responses.Neuroscience and Biobehavioral Reviews 2000;24:485-501