Lalley P M
J Pharmacol Exp Ther. 1980 Nov;215(2):418-25.
Several general anesthetics and baclofen (Lioresal), an analog of gamma-aminobutyric acid, were tested for their effects on reflexes evoked by stimulation of afferent fibers in the carotid sinus nerve, aortic nerve and cervical vagus nerve. In both anesthetized and decerebrate unanesthetized cats, baclofen, barbiturates (methohexital and pentobarbital) and alpha-chloralose converted depressor responses evoked by afferent fiber stimulation to pressor episodes. The original depressor responses were reinstated temporarily by the gamma-aminobutyric acid antagonists bicuculline and picrotoxin, but not by strychnine or pentylenetetrazol. Baclofen, chloralose and barbiturate general anesthetics also blocked the inhibition of aortic nerve, carotid sinus nerve and vagus nerve stimulation of neural sympathetic vasomotor discharges. Other general anesthetics (halothane, nitrous oxide, urethane and ketamine) did not have these effects. The effects of baclofen, barbiturates and chloralose are attributed to selective blockade of baroreceptor reflexes. It is suggested that the underlying mechanism may be related to enhancement or imitation of the action of gamma-aminobutyric acid at central vasomotor synapses.
研究了几种全身麻醉药以及γ-氨基丁酸类似物巴氯芬（力奥来素）对刺激颈动脉窦神经、主动脉神经和颈迷走神经传入纤维所诱发反射的影响。在麻醉猫和去大脑未麻醉猫中，巴氯芬、巴比妥类药物（美索比妥和戊巴比妥）以及α-氯醛糖可将传入纤维刺激诱发的降压反应转变为升压发作。γ-氨基丁酸拮抗剂荷包牡丹碱和印防己毒素可使原来的降压反应暂时恢复，但士的宁或戊四氮则不能。巴氯芬、氯醛糖和巴比妥类全身麻醉药还可阻断主动脉神经、颈动脉窦神经和迷走神经刺激对神经交感血管运动放电的抑制作用。其他全身麻醉药（氟烷、氧化亚氮、乌拉坦和氯胺酮）则无这些作用。巴氯芬、巴比妥类药物和氯醛糖所产生的效应归因于对压力感受器反射的选择性阻断。提示其潜在机制可能与增强或模拟γ-氨基丁酸在中枢血管运动突触处的作用有关。
