RENAL SYMPATHETIC NERVE ACTIVITY DURING SHOCK

1998-1999年，在清醒家兔中观察了急性心脏压塞（CT）时肾交感神经活动（RNA）的变化。在INT兔中，当开始CT时，RNA在平均动脉压（MAP）保持期间增加到200%以上，而随后注射盐水时，RNA下降到一半以下，同时MAP急剧下降。如果在CT二次注射前给予7-硝基吲唑，则可明显阻止CT失代偿引起的RNA下降，并使大脑皮质和延髓的一氧化氮合酶活性分别抑制48%和44%。在BRD兔中，RNA在整个CT中没有改变，但在注射纳洛酮时增加。在CND兔中，RNA在补偿CT期间增加，但在去腐过程中不减少。 关于我们 这些结果表明，CT对RNA的反应是双相的，代偿期CT时RNA增加，失代偿期CT时RNA减少。窦主动脉压力感受器参与介导RNA的增加，而心脏感受器可能参与介导RNA的减少。失代偿期CT时RNA的突然减少可能是由NO或中枢神经系统的内源性阿片类物质介导的。本文研究了心源性和失血性休克对RNA和压力感受性反射的影响。CT最初增加RNA，随后下降至基线以下。迷走神经切断可使压力反射衰减消失。然而，失血性休克增加RNA最初，随后恢复到基线。颈迷走神经切断术后，两种休克状态下RNA水平均高于INT组。释放CT后压力感受性反射敏感性迅速减弱，而出血恢复后压力感受性反射敏感性无明显减弱。这些结果表明，CT时交感神经活动可能比出血时减弱更严重，心源性休克通过迷走神经传入减弱压力感受性反射。少

During 1998-1999, renal sympathetic nerve activity (RNA) responses to acute cardiac tamponade (CT) were studied in conscious rabbits with all reflexes intact (INT) or after sinoaortic baroreceptor denervation (BRD) or cardiac nerve denervation (CND). In INT rabbits, the RNA increased to over 200% during the mean arterial pressure (MAP) mentained when the CT was started, whereas the RNA decreased to below half and at the same time the MAP decreased sharply by subsequent injection of saline. After that, an administration of naloxone resulted in increases in both MAP and RNA.If 7-nitroindazole was admitted before the biginning of CT, the decline in RNA caused by decompensated CT was markedly prevented and brain nitric oxide synthase activity in the cerebral cortex and medulla oblongata was inhibited by 48% and 44%. In BRD rabbits, RNA did not alter throughout CT, but increased on injection of naloxone. In CND rabbits, RNA increased during compensated CT but did not decrease during decompe … More nsated CT.These results indicate that RNA responses to CT are biphasic, with an increase during conpensated CT and a decrease during decompensated CT.Sinoaortic baroreceptors are involved in mediating the increase in RNA, whereas cardiac receptors may be involved in mediating the decrease in RNA The abrupt decrease in RNA during decompensated CT may be mediated by NO or endogenous opioid in the central nervous system.In 2000, it was studied that the effects of cardiogenic or hemorrhagic shock on RNA and baroreflex. CT increased RNA initially, followed by decline below baseline. Vagotomy abolished the baroreflex attenuation. However, hemorrhagic shock increased RNA initially, followed by recovery toward baseline. Cervical vagotomy maintained RNA at higher level than those of INT rabbits on both shock. The baroreflex sensitivity was significantly attenuated soon after releasing CT.In contrast to CT, the baroreflex sinsitivity was not attenuated after hemorrhage recovering. These results indicated that sympathetic nerve activity may be attenuated more heavily in CT than hemorrhage, and cardiogenic shock attenuated the baroreflex via vagal afferents. Less