Muscarinic receptor regulation of synaptic transmission in airway parasympathetic ganglia.
Muscarinic receptor regulation of synaptic transmission in airway parasympathetic ganglia.
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毒蕈碱受体对气道副交感神经节突触传递的调节。
DOI：
10.1152/ajplung.1996.270.4.l630
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Undem,BJ
中科院分区：
文献类型：
--
作者：
Myers,AC;Undem,BJ
用细胞内记录内源性神经节神经元的方法，研究毒碱受体对豚鼠支气管副交感神经节突触传递的调节作用。乙酰甲胆碱(1微米)可使迷走神经刺激的快速兴奋性突触后电位(FEPSP)的幅度分别降低33%和46%(0.8和8.0赫兹)，但对沐浴尼古丁受体激动剂引起的去极化幅度无影响。甲氧西林(1微米)可抑制乙酰甲胆碱对fEPSP的作用，但不影响刺激迷走神经诱发的fEPSP的幅度。乙酰甲胆碱(10微米)使神经元亚群去极化(约4 mV)，这一作用可被哌仑西平(0.1微米)阻断。在其他神经元中，要么没有效应，要么有很小的超极化(1-5 mV)。与刺激迷走神经(节前)引起的胆碱能收缩一样，甲氧曲明对电场刺激引起的支气管平滑肌胆碱能收缩也有增强作用。结果表明，M2受体的激活可抑制突触前乙酰胆碱的释放，从而显着抑制支气管副交感神经节的突触传递。然而，当在体外环境中研究时，这种神经调节效应的生理作用似乎是有限的。
Muscarinic receptor regulation of synaptic transmission in guinea pig bronchial parasympathetic ganglia was evaluated with the use of intracellular recording of the intrinsic ganglion neurons. Methacholine (1 microM) decreased the amplitude of vagus nerve-stimulated fast excitatory postsynaptic potentials (fEPSP) by 33 and 46% (at 0.8 and 8.0 Hz, respectively) but had no effect on the amplitude of the depolarizations evoked by a bath-applied nicotinic receptor agonist. Methoctramine (1 microM) inhibited methacholine's effect on fEPSP but alone did not influence the magnitude of the fEPSP evoked by vagus nerve stimulation. Methacholine (10 microM) depolarized a subpopulation of neurons (approximately 4 mV), which was blocked by pirenzepine (0.1 microM). In other neurons, either no effect or a small (1-5 mV) hyperpolarization was noted. Cholinergic contractions of bronchial smooth muscle elicited by electrical field stimulation were potentiated by methoctramine to the same extent as those evoked by vagus nerve (preganglionic) stimulation. The data indicate that M2 receptor activation can lead to inhibition of presynaptic acetylcholine release and consequently a significant inhibition of synaptic transmission in bronchial parasympathetic ganglia. The physiological role of this neuromodulatory effect appears limited, however, when studied in the in vitro setting.