Barringer D L, Buñag R D
Department of Pharmacology, College of Health Sciences, and Hospital University of Kansas Medical Center, Kansas City 66103.
J Cardiovasc Pharmacol. 1990 Jan;15(1):10-5. doi: 10.1097/00005344-199001000-00002.
To assess anesthetic alteration of chronotropic baroreflexes, arterial pressure and heart rate (HR) were monitored continuously during intravenous (i.v.) infusions of phenylephrine or sodium nitroprusside in rats that were either awake or anesthetized (with pentobarbital, urethane, or chloralose). Ensuing reflex HR responses during each drug infusion were determined in two ways: (a) at 10-s intervals (time analysis), and (b) with every 5-mm Hg change in pressure (pressure analysis). Results were less variable with pressure than with time analysis. With responses from awake rats as a basis for comparison, pressure analysis showed that pentobarbital greatly attenuated both reflex tachycardia and bradycardia, whereas urethane and chloralose reduced only reflex tachycardia. Depression by pentobarbital of both reflex tachycardia and bradycardia suggests severe attenuation of both sympathetic and parasympathetic tone. In contrast, preferential alteration of reflex tachycardia by chloralose and urethane implies a greater attenuation of sympathetic than parasympathetic tone.
为评估变时性压力反射的麻醉改变，在清醒或麻醉（用戊巴比妥、乌拉坦或氯醛糖）的大鼠静脉输注去氧肾上腺素或硝普钠期间，持续监测动脉血压和心率（HR）。每次药物输注期间随后的反射性心率反应通过两种方式确定：（a）以10秒间隔（时间分析），以及（b）每次压力变化5 mmHg时（压力分析）。与时间分析相比，压力分析的结果变异性较小。以清醒大鼠的反应作为比较基础，压力分析表明戊巴比妥极大地减弱了反射性心动过速和心动过缓，而乌拉坦和氯醛糖仅降低了反射性心动过速。戊巴比妥对反射性心动过速和心动过缓的抑制表明交感神经和副交感神经张力均严重减弱。相比之下，氯醛糖和乌拉坦对反射性心动过速的优先改变意味着交感神经张力比副交感神经张力减弱得更多。
