Taneyama C, Benson K T, Hild P G, Goto H
Department of Anesthesiology, University of Kansas Medical Center, Kansas City 66160-7415, USA.
J Pharmacol Exp Ther. 1997 Feb;280(2):570-5.
We previously reported that ATP, but not adenosine, administered i.v. attenuates the baroreflex-mediated increase in sympathetic nerve activity in response to arterial hypotension by a vagal afferent mechanism. It was not elucidated in that study which vagal afferent endings are involved. Mongrel dogs were anesthetized with alpha-chloralose, thoracotomy was performed and a 27-gauge hypodermic needle was inserted into the left circumflex coronary artery. The left renal sympathetic nerves were isolated and placed on a bipolar silver electrode for measurement of renal sympathetic nerve activity (RSNA). Dose-response effects of intracoronary or i.v. infusion of ATP (100, 200 or 400 microg/kg/min) on RSNA and mean arterial pressure were studied in neuraxis-intact and cervically vagotomized dogs. RSNA was increased dose-dependently with decreasing mean arterial pressure during the i.v. ATP infusion. Elevation of RSNA was attenuated by higher intracoronary ATP infusion rates, despite the fact that mean arterial pressure was decreased dose-dependently. Left ventricular end-diastolic pressure, however, remained unchanged. This suppression of RSNA by the intracoronary ATP infusion was completely abolished by bilateral cervical vagotomy. Our data suggest that ATP attenuates reflex increases in sympathetic nerve activity by possibly stimulating ventricular chemoreceptors with cardiac vagal afferents.
我们之前报道过，静脉注射ATP而非腺苷，可通过迷走神经传入机制减弱压力反射介导的交感神经活动增加，以应对动脉低血压。该研究未阐明涉及哪些迷走神经传入末梢。用α-氯醛糖麻醉杂种犬，进行开胸手术，并将一根27号皮下注射针插入左旋冠状动脉。分离左肾交感神经并置于双极银电极上，用于测量肾交感神经活动（RSNA）。在神经轴完整和颈部迷走神经切断的犬中，研究了冠状动脉内或静脉输注ATP（100、200或400μg/kg/min）对RSNA和平均动脉压的剂量反应效应。静脉输注ATP期间，RSNA随平均动脉压降低呈剂量依赖性增加。尽管平均动脉压呈剂量依赖性降低，但冠状动脉内较高的ATP输注速率可减弱RSNA的升高。然而，左心室舒张末期压力保持不变。双侧颈部迷走神经切断完全消除了冠状动脉内ATP输注对RSNA的这种抑制作用。我们的数据表明，ATP可能通过刺激具有心脏迷走神经传入的心室化学感受器来减弱交感神经活动的反射性增加。
