Vasopressor nerve responses in the pithed rat, previously identified as α₂-adrenoceptor mediated, may be α_1D-adrenoceptor mediated

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• 作者：James R. Docherty ; ^a ; ^{docherty@rcsi.ie}
• 关键词：&#x3b1 ; _1A-adrenoceptor ; &#x3b1 ; _1D-adrenoceptor ; &#x3b1 ; ₂-adrenoceptor ; &#x3b1 ; _2A-adrenoceptor ; Vasopressor nerve responses ; (Pithed rat)
• 刊名：European Journal of Pharmacology
• 出版年：2011
• 出版时间：11 May 2011
• 年：2011
• 卷：658
• 期：2-3
• 页码：182-186
• 全文大小：262 K

文摘

Responses to pressor nerve stimulation in the pithed rat have been variously described as mediated, at least in part, by α₂-adrenoceptors and by α_1A and α_1D-adrenoceptors. We have examined the subtypes of α-adrenoceptor involved in rises in diastolic blood pressure in the pithed rat preparation produced by vasopressor nerve stimulation with 10 pulses at 1 Hz or 20 pulses at 5 Hz. Vasopressor nerve responses to 1 Hz stimulation were markedly inhibited by the α_1A-adrenoceptor antagonist RS 100329 (0.1 mg/kg) and by the α_1D-adrenoceptor antagonist BMY 7378 (0.1 mg/kg). The α₂-adrenoceptor antagonist yohimbine (0.1 mg/kg) significantly increased pressor nerve responses to 1 Hz stimulation, but yohimbine (1 mg/kg) significantly reduced pressor nerve responses. However, following BMY 7378 (0.1 mg/kg), yohimbine (1 mg/kg) did not produce any further inhibition of pressor nerve responses to 1 Hz stimulation. The α_2A-adrenoceptor antagonist BRL 44408 (1 mg/kg) did not reduce pressor responses to 1 Hz stimulation. BMY 7378 produced much less inhibition of pressor nerve responses to 5 Hz stimulation, whereas RS 100329 produced similar inhibition of 1 Hz and 5 Hz responses. Yohimbine (0.1 and 1 mg/kg) did not significantly affect pressor nerve responses to 5 Hz stimulation. In conclusion, pressor nerve responses in the pithed rat involve both α_1A and α_1D-adrenoceptor, but there is no clear evidence for the involvement of α₂-adrenoceptors.