Huchet A M, Doursout M F, Ostermann G, Chelly J, Schmitt H
Neuropharmacology. 1983 Nov;22(11):1243-8. doi: 10.1016/0028-3908(83)90196-x.
In anaesthetized and bilaterally vagotomized dogs, reflex bradycardia elicited by intravenous injection of noradrenaline was facilitated by AR-C 239, a new alpha 1-adrenoceptor blocking drug and inhibited by the alpha 2-adrenoceptor antagonist, yohimbine. Both alpha-blocking drugs were administered into the vertebral artery. In another group of bilaterally vagotomized dogs, unilateral electrical stimulation of the carotid sinus nerve induced a frequency-dependent decrease in mean blood pressure solely mediated through the sympatho-inhibitory component of the baroreflex. Administration of the alpha 1-adrenoceptor blocking drugs, AR-C 239 and prazosin (5 micrograms/kg) into the vertebral artery decreased basal mean blood pressure and increased depressor responses to the carotid sinus nerve stimulation, whereas the intracisternal injection of phenylephrine (30 micrograms/kg), a preferential alpha 1-agonist, increased mean blood pressure but inhibited the hypotension resulting from electrical stimulation. In addition, the injection into the vertebral artery of yohimbine (100 micrograms/kg), an alpha 2-adrenoceptor blocking agent which caused no change in mean arterial pressure, inhibited the decrease in the sympathetic component. In conclusion, these results suggest the possible participation of the two types of alpha-adrenoceptors in the modulation of the sympathetic component of the baroreflex: alpha 1-adrenoceptor stimulation could inhibit, whereas alpha 2-adrenoceptor activation facilitates the reflex activity in the sympathetic fibres.
在麻醉且双侧迷走神经切断的犬中，静脉注射去甲肾上腺素诱发的反射性心动过缓可被新型α1肾上腺素能受体阻断药AR - C 239增强，而被α2肾上腺素能受体拮抗剂育亨宾抑制。两种α阻断药均经椎动脉给药。在另一组双侧迷走神经切断的犬中，单侧电刺激颈动脉窦神经仅通过压力感受性反射的交感抑制成分介导引起平均血压的频率依赖性降低。经椎动脉给予α1肾上腺素能受体阻断药AR - C 239和哌唑嗪（5微克/千克）可降低基础平均血压，并增强对颈动脉窦神经刺激的降压反应，而脑池内注射去氧肾上腺素（30微克/千克），一种选择性α1激动剂，可升高平均血压，但抑制电刺激引起的低血压。此外，经椎动脉注射育亨宾（100微克/千克），一种不引起平均动脉压变化的α2肾上腺素能受体阻断剂，可抑制交感成分的降低。总之，这些结果提示两种类型的α肾上腺素能受体可能参与压力感受性反射交感成分的调节：刺激α1肾上腺素能受体可抑制，而激活α2肾上腺素能受体可促进交感神经纤维的反射活动。
