Local circuitry regulates the excitability of rat neurohypophysial neurones
Local circuitry regulates the excitability of rat neurohypophysial neurones
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DOI：
10.1111/j.1469-445x.2000.tb00019.x
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发表时间：
2000-03-01
影响因子：
2.7
通讯作者：
Latchford, KJ
中科院分区：
文献类型：
--
作者：
Ferguson, AV;Latchford, KJ
血管紧张素II（AII）和谷氨酸在神经内分泌调节中的重要性早已被认识到。然而，AII和谷氨酸调节室旁核（PVN）的兴奋性的机制在很大程度上仍然是一个谜，直到最近。现在很明显，AII和谷氨酸是大鼠PVN中大细胞和小细胞神经元的有效刺激物。虽然谷氨酸，在中枢神经系统中的主要兴奋性神经递质，无处不在的兴奋PVN神经元，AII似乎介导的PVN的兴奋性的直接和间接的机制。有趣的是，这两种神经递质在兴奋PVN时激活抑制性反馈系统，该系统能够减少初始刺激。在生理上，这调节了PVN的输出信号，可能也调节了神经垂体的神经肽释放。这种负反馈回路的重要性在系统中断的病理生理学意义上是显而易见的。有证据表明，这一系统的故障可能是部分负责的充血性心力衰竭和高血压的发病和维持。未来的研究将继续表征谷氨酸和AII在PVN中的作用，并进一步阐明控制PVN兴奋性的机制。
The importance of angiotensin II (AII) and glutamate has long since been recognized in neuroendocrine regulation. However, the mechanisms by which AII and glutamate modulate the excitability of the paraventricular nucleus (PVN) have largely remained a mystery until recently. It is now apparent that AII and glutamate are potent stimulators of both magnocellular and parvocellular neurones in the rat PVN. While glutamate, the predominant excitatory neurotransmitter in the CNS, ubiquitously excites PVN neurones, AII appears to mediate excitability of the PVN by both direct and indirect mechanisms. Interestingly, both of these neurotransmitters, upon exciting the PVN, activate an inhibitory feedback system, which is capable of diminishing the initial stimulus. Physiologically, this moderates the output signals from the PVN, and probably also regulates neuropeptide release from the neurohypophysis. The importance of this negative-feedback loop is evident in the pathophysiological implications of a disruption in the system. Evidence suggests that a breakdown in this system may be responsible in part for the onset and maintenance of both congestive heart failure and hypertension. Future studies will continue to characterize both the actions of glutamate and AII in the PVN, and to further elucidate the mechanisms which control the excitability of the PVN.