Thrasher T N, Keenan C R, Ramsay D J
Department of Surgery, University of Maryland, Baltimore, Maryland 21201, USA.
Am J Physiol. 1999 Sep;277(3):R795-801. doi: 10.1152/ajpregu.1999.277.3.R795.
Arterial hypotension stimulates increases in plasma arginine vasopressin (AVP), plasma renin activity (PRA), and water intake in conscious dogs. We have previously reported that increasing left atrial but not right atrial pressure completely blocks the increase in plasma AVP and PRA induced by hypotension. The goal of the present study was to examine the effect of increasing right or left atrial pressure on water intake induced by arterial hypotension. Dogs were prepared with occluding cuffs on the thoracic inferior vena cava, the pulmonary artery, and the ascending aorta. We reduced mean arterial pressure (MAP) 25% below control by either inferior vena cava constriction (IVCC), pulmonary artery constriction (PAC), or ascending aorta constriction (AAC) and measured water intake over a 2-h period. Cumulative water intake during IVCC (n = 6) and PAC (n = 6) was 7.8 +/- 2.0 and 6.7 +/- 2.6 ml/kg, respectively. There was no difference between either the latency or the volume consumed between the two treatments. In contrast, none of the dogs drank during hypotension induced by AAC (n = 5). Because the degree of arterial baroreceptor unloading was the same in each treatment by design, we conclude that stimulation of left atrial receptors inhibits drinking in response to arterial hypotension but that stimulation of right atrial receptors has no effect on the response in dogs.
动脉低血压会刺激清醒犬的血浆精氨酸血管加压素（AVP）、血浆肾素活性（PRA）升高以及饮水增加。我们之前报道过，增加左心房压力而非右心房压力可完全阻断低血压诱导的血浆AVP和PRA升高。本研究的目的是探讨增加右心房或左心房压力对动脉低血压诱导的饮水的影响。给犬在胸段下腔静脉、肺动脉和升主动脉处放置阻塞袖带。我们通过下腔静脉缩窄（IVCC）、肺动脉缩窄（PAC）或升主动脉缩窄（AAC）使平均动脉压（MAP）比对照降低25%，并在2小时内测量饮水量。IVCC组（n = 6）和PAC组（n = 6）的累积饮水量分别为7.8±2.0和6.7±2.6 ml/kg。两种处理之间的潜伏期或饮水量均无差异。相比之下，AAC诱导低血压期间（n = 5）没有犬饮水。由于按设计每种处理中动脉压力感受器卸载的程度相同，我们得出结论，刺激左心房感受器可抑制对动脉低血压的饮水反应，但刺激右心房感受器对犬的这种反应没有影响。
