摘要
[目的]研究α-氨基-3-羟基-5-甲基-4-异恶唑丙酸(AMPA)受体棕榈酰化修饰在亚慢性铝染毒在大鼠海马长时程增强(LTP)中的作用。[方法]健康成年雄性SD大鼠24只,按体重相近者随机分为对照组、低剂量组、中剂量组、高剂量组,每组6只,采用腹腔注射麦芽酚铝的方式对大鼠进行染毒,对照组给予生理盐水,低、中、高剂量组的铝染毒剂量分别为10、20、40μmol/kg,隔天染毒,共染毒12周。染毒结束后采用在体海马CA1区LTP记录技术,记录兴奋性突触后电位,然后断头取海马,采用酰基生物素置换法测定AMPA受体棕榈酰化水平。[结果] LTP检测结果显示,高频刺激后1 min和60 min时,各剂量组的标准化幅值(后简称"幅值")差异有统计学意义(P<0.05);30 min时差异无统计学意义。1 min时,中、高剂量组的幅值低于对照组和低剂量组,差异均有统计学意义(P<0.05)。60 min时,低、中、高剂量组的幅值均低于对照组,且高剂量组的幅值低于低、中剂量组,差异均有统计学意义(P<0.05)。酰基生物素置换法结果显示,中、高剂量组的离子型谷氨酸受体1(GluR1)低于对照组,差异有统计学意义(P<0.05);中剂量组的离子型谷氨酸受体2(GluR2)棕榈酰化水平低于对照组,高剂量组的GluR2棕榈酰化水平低于对照组及低、中剂量组,差异均有统计学意义(P<0.05)。[结论]亚慢性铝染毒后,大鼠海马LTP受到抑制,AMPA受体棕榈酰化水平降低,这提示AMPA受体棕榈酰化降低可能是LTP损害的机制之一。
[Objective] To study the effect of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid(AMPA) receptor palmitoylation modification on long-term potentiation in rat hippocampus by subchronic exposure to aluminum.[Methods] Twenty-four healthy adult male SD rats were randomly divided by weight into control group,low-dose group,middledose group,and high-dose group,and administered with saline(control group) or Al(mal)3(10,20,and 40 μmol/kg) via intraperitoneal injection every two days for 12 weeks.Field excitatory post-synaptic potentials in CA1 region were recorded by field LTP record technique in vivo,and AMPA receptor palmitoylation was examined by acyl-biotin exchange method.[Results] The results of LTP record showed that the standardized amplitude(hereinafter referred to as "amplitude") of each group was significantly different at 1 min and 60 min after high frequency stimulation(P<0.05),but not at 30 min.The amplitudes of the middle-and high-dose groups were statistically lower than those of the control group and the low dose group at 1min(P<0.05).The amplitudes of the three dose groups were significantly lower than that of the control group at 60 min,and the amplitude of the high-dose group was significantly lower than those of the low-and middle-dose groups at 60 min(P<0.05).The results of acyl-biotin exchange showed that the glutamate receptor 1(GluR1) palmitoylation levels of the middle-and high-dose groups were statistically lower than that of the control group(P<0.05);the glutamate receptor 2(GluR2) palmitoylation level in the middle-dose group was statistically lower than that of the control group,and the GluR2 palmitoylation level in the high-dose group was statistically lower than those of the control,low-dose,and middle-dose groups(P<0.05).[Conclusion] Long-term potentiation in rat hippocampus is inhibited and palmitoylation of AMPA receptor is reduced after subchronic aluminum exposure,suggesting that the reduction of palmitoylation of AMPA receptor may be one of the mechanisms of LTP damage.
引文
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