Carlson S H, Wyss J M
Vascular Biology and Hypertension Program, Department of Medicine, and Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA.
Am J Physiol. 1999 Jul;277(1):E161-7. doi: 10.1152/ajpendo.1999.277.1.E161.
Peripheral osmoreceptors monitor dietary NaCl and modify central nervous system and renal sympathetic nervous system activity accordingly. Experimental evidence suggests that these responses are dependent on the hepatic nerves. Peripheral osmoreceptors also modify arginine vasopressin (AVP) secretion. However, although hepatic denervation reportedly blunts activation of both supraoptic and paraventricular hypothalamic neurons after intraportal NaCl infusion, the role of the hepatic nerves in the AVP release has not been directly examined. The present study tests the hypothesis that the hepatic nerves modify AVP release in response to intragastric NaCl infusion. Wistar-Kyoto rats (WKY) received either hepatic denervation or a sham operation. Intragastric NaCl infusion significantly elevated plasma AVP in both sham-operated WKY and hepatic-denervated WKY, and the responses were not different between these groups. Second, previous studies suggest that both AVP secretion and baroreflexes are blunted in spontaneously hypertensive rats (SHR), deficits that contribute to the observed hypertension in SHR. We hypothesized that SHR also have a blunted peripheral osmoreceptor reflex and that this contributes to NaCl-sensitive hypertension. In contrast to our prediction, in SHR intragastric NaCl infusion induced an increase in plasma AVP that was similar to that in the WKY groups. Thus, although hepatic osmoreceptors are important for chronic regulation of arterial pressure, renal sympathetic nervous system activity, and the activity of hypothalamic neurons, they do not appear to influence plasma AVP concentration in response to intragastric NaCl.
外周渗透压感受器监测饮食中的氯化钠，并相应地改变中枢神经系统和肾交感神经系统的活动。实验证据表明，这些反应依赖于肝神经。外周渗透压感受器还会改变精氨酸加压素（AVP）的分泌。然而，尽管据报道肝去神经支配会减弱门静脉内注入氯化钠后视上核和室旁核下丘脑神经元的激活，但肝神经在AVP释放中的作用尚未得到直接研究。本研究检验了肝神经会改变胃内注入氯化钠后AVP释放这一假说。Wistar-Kyoto大鼠（WKY）接受肝去神经支配或假手术。胃内注入氯化钠使假手术WKY组和肝去神经支配WKY组的血浆AVP均显著升高，且两组间的反应无差异。其次，先前的研究表明，自发性高血压大鼠（SHR）的AVP分泌和压力反射均减弱，这些缺陷导致了SHR中观察到的高血压。我们假设SHR的外周渗透压感受器反射也减弱，且这导致了对氯化钠敏感的高血压。与我们的预测相反，在SHR中，胃内注入氯化钠诱导的血浆AVP升高与WKY组相似。因此，尽管肝渗透压感受器对动脉血压、肾交感神经系统活动和下丘脑神经元活动的慢性调节很重要，但它们似乎并不影响胃内注入氯化钠后血浆AVP的浓度。
