Differential sensitivity of GABAergic and glycinergic inputs to orexin-A in preganglionic cardiac vagal neurons of newborn rats

• 来源期刊: 中国药理学报(英文版)
• 关键词: patch-clamp techniques nervous system synaptic transmission vagus nerve
• 年，卷（期）: 2005,（12）
• 页码范围: 1442-1447
• 页数: 6页
• 语种: 英文

摘要

Aim: To test the effect of orexin-A (hypocretin-1), a neuropeptide synthesized in the lateral hypothalamus and the perifornical area, on the glycinergic inputs and the GABAergic inputs of cardiac vagal neurons (CVN). Methods: The effects of orexin-A at three concentrations (20 nmol/L, 100 nmol/L, 500 nmol/L) on the glycinergic inputs and the GABAergic inputs were investigated by using retrograde fluorescent labeling of cardiac neurons (CVN) in the nucleus ambiguus (NA) and the voltage patch-clamp technique. Results: Orexin-A dose-dependently increased the frequency of both the glycinergic and the GABAergic spontaneous inhibitory postsynaptic currents (sIPSC). However, at a lower concentration (20 nmol/L) of orexin-A, although the frequency of the glycinergic sIPSC was significantly increased, the frequency of the GABAergic sIPSC was not significantly changed. Conclusion: The glycinergic inputs and the GABAergic inputs have different sensitivities to orexin-A, which suggests that the two kinds of inhibitory inputs might play different roles in the synaptic control of cardiac vagal functions.