Stekiel T A, Ozono K, McCallum J B, Bosnjak Z J, Stekiel W J, Kampine J P
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
Anesthesiology. 1990 Dec;73(6):1169-78. doi: 10.1097/00000542-199012000-00015.
Potent inhalational anesthetics depress autonomic reflex responses at multiple sites. Most studies emphasize cardiac chronotropic changes and changes in systemic blood pressure. Recently, active reflex venoconstriction of 500-1,000 microns O.D. mesenteric veins has been demonstrated. In the current study, the effects of halothane on the reflex responses of similar mesenteric veins were measured. Mesenteric vein diameter and intravenous pressure were measured in 500-1,000 microns O.D. veins from the mesentery of segments of terminal ileum externalized in situ from 27 New Zealand white rabbits anesthetized with alpha-chloralose. Mean arterial pressure was measured with femoral arterial cannulation, and heart rate was determined from the arterial pressure signal. In a separate group of six animals, sympathetic efferent nerve activity was measured from a postganglionic splanchnic nerve. Reflex venoconstriction and increases in mean arterial pressure and mesenteric vein pressure in response to bilateral carotid occlusion were attenuated by 0.5% and 1% inhaled halothane but not by superfusate equilibrated with 3% halothane. Decreases in mesenteric vein diameter and increases in mesenteric vein pressure in response to celiac ganglion stimulation were unaffected by both 0.5% inhaled halothane and superfusate equilibrated with 5% halothane. The bilateral carotid occlusion reflex-mediated increase in sympathetic efferent nerve activity was depressed by both 0.5% and 1% inhaled halothane. The effect of inhaled halothane on prestimulation baseline vein diameter was inconsistent. Superfusate equilibrated with 5% but not 3% halothane caused baseline venodilation. These results suggest a mechanism whereby control of venous tone is inhibited by halothane proximal to the postganglionic neuron. This could involve central or ganglionic inhibition.
强效吸入麻醉剂会在多个部位抑制自主反射反应。大多数研究着重于心脏变时性变化和全身血压变化。最近，已证实外径为500 - 1000微米的肠系膜静脉存在主动反射性血管收缩。在本研究中，测量了氟烷对类似肠系膜静脉反射反应的影响。在27只经α - 氯醛糖麻醉的新西兰白兔原位外置的回肠末端节段肠系膜中，测量外径为500 - 1000微米静脉的肠系膜静脉直径和静脉压力。通过股动脉插管测量平均动脉压，并从动脉压力信号确定心率。在另一组6只动物中，从节后内脏神经测量交感传出神经活动。吸入0.5%和1%氟烷可减弱双侧颈动脉闭塞引起的反射性血管收缩以及平均动脉压和肠系膜静脉压力的升高，但与3%氟烷平衡的灌流液则无此作用。吸入0.5%氟烷和与5%氟烷平衡的灌流液均未影响腹腔神经节刺激引起的肠系膜静脉直径减小和肠系膜静脉压力升高。吸入0.5%和1%氟烷均抑制了双侧颈动脉闭塞反射介导的交感传出神经活动增加。吸入氟烷对刺激前基线静脉直径的影响并不一致。与5%氟烷而非3%氟烷平衡的灌流液导致基线静脉扩张。这些结果提示了一种机制，即氟烷在节后神经元近端抑制静脉张力的控制。这可能涉及中枢或神经节抑制。
