Stadnicka A, Stekiel T A, Bosnjak Z J, Kampine J P
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
Anesthesiology. 1993 May;78(5):928-36. doi: 10.1097/00000542-199305000-00018.
Halothane and isoflurane are known to attenuate neurally mediated regulation of mesenteric vein diameter. The current study evaluated the effects of enflurane on baroreflex control of small mesenteric veins.
Changes in mesenteric vein diameter, intravenous pressure, mean arterial pressure, and heart rate in response to bilateral carotid occlusion, aortic nerve stimulation, and celiac ganglion stimulation were measured in 23 chloralose-anesthetized rabbits before, during, and after 1% and 2% inhaled enflurane administration. In six other rabbits, sympathetic efferent nerve activity was recorded directly from a postganglionic splanchnic nerve, also during bilateral carotid occlusion and aortic nerve stimulation, before, during, and after inhalation of 1% and 2% enflurane.
Baseline mean arterial pressure and heart rate decreased, and mesenteric vein diameter increased, in response to inhaled enflurane. Reflex venoconstriction and the increases in mean arterial pressure, intravenous pressure, and heart rate, in response to bilateral carotid occlusion, were significantly inhibited at both levels of inhaled enflurane. Decreases in mean arterial pressure and heart rate, and reflex venodilation in response to aortic nerve stimulation, were attenuated by 2%, but not 1%, enflurane. Mesenteric venoconstriction, blood pressure increase, and bradycardia in response to celiac ganglion stimulation were unaffected by 2% inhaled and 5% superfused enflurane. Both 1% and 2% inhaled enflurane attenuated resting and carotid sinus-mediated increases in sympathetic efferent nerve activity.
These results indicate that enflurane alters splanchnic venous reflexes in large part via the inhibition of sympathetic efferent activity.
已知氟烷和异氟烷可减弱神经介导的肠系膜静脉直径调节。本研究评估了恩氟烷对小肠系膜静脉压力感受性反射控制的影响。
在23只氯醛糖麻醉的家兔中，测量吸入1%和2%恩氟烷之前、期间和之后，双侧颈动脉闭塞、主动脉神经刺激以及腹腔神经节刺激引起的肠系膜静脉直径、静脉压、平均动脉压和心率的变化。在另外6只家兔中，同样在吸入1%和2%恩氟烷之前、期间和之后，双侧颈动脉闭塞和主动脉神经刺激时，直接记录节后内脏神经的交感传出神经活动。
吸入恩氟烷后，基线平均动脉压和心率降低，肠系膜静脉直径增加。在两个吸入恩氟烷水平下，双侧颈动脉闭塞引起的反射性静脉收缩以及平均动脉压、静脉压和心率的增加均受到显著抑制。2%恩氟烷可减弱主动脉神经刺激引起的平均动脉压和心率降低以及反射性静脉舒张，但1%恩氟烷无此作用。吸入2%恩氟烷和灌注5%恩氟烷对腹腔神经节刺激引起的肠系膜静脉收缩、血压升高和心动过缓无影响。吸入1%和2%恩氟烷均减弱了静息和颈动脉窦介导的交感传出神经活动增加。
这些结果表明，恩氟烷在很大程度上通过抑制交感传出活动改变内脏静脉反射。
