Yarosh C A, Acosta C G, Ashe J H
Department of Psychology, University of California, Riverside 92521.
Synapse. 1988;2(2):174-82. doi: 10.1002/syn.890020209.
The influence of slow muscarinic postsynaptic potentials, i.e., the s-IPSP and s-EPSP, on synaptic transmission mediated through nicotinic receptors was studied in the superior cervical ganglion of the rabbit. Postganglionic spikes and synaptic potentials were elicited by delivery of conditioning and test stimulus pulses to afferent fibers. When paired stimulus volleys were separated by brief intervals (20-100 msec) or long intervals (1,000-8,000 msec), the population spike elicited by the test stimulus was larger in amplitude than that elicited by the conditioning volley. When paired stimulus volleys were separated by 250-500 msec, the amplitude of the population spike elicited by the test volley was smaller than that elicited by the conditioning stimulus. Gallamine, which selectively blocks the s-IPSP, reduced the suppression of the test spike which occurred when stimulus IPIs ranged between 250-500 msec. Pirenzepine, which selectively blocks the s-EPSP, reduced the late facilitation of test postganglionic spikes which occurred with stimulus IPIs greater than 1,000 msec. The non-selective muscarinic antagonist QNB, produced changes in postganglionic spike amplitude that were similar to the combined effects of gallamine and pirenzepine. The evidence indicates that the s-IPSP and s-EPSP modified the excitability state of the ganglionic neurons and subsequent synaptic transmission that was mediated through nicotinic receptors.
在兔颈上神经节中，研究了缓慢的毒蕈碱型突触后电位，即慢抑制性突触后电位（s-IPSP）和慢兴奋性突触后电位（s-EPSP），对通过烟碱型受体介导的突触传递的影响。通过向传入纤维施加条件刺激和测试刺激脉冲来诱发节后锋电位和突触电位。当配对刺激脉冲串间隔较短（20 - 100毫秒）或较长（1000 - 8000毫秒）时，测试刺激诱发的群体锋电位幅度大于条件刺激诱发的群体锋电位幅度。当配对刺激脉冲串间隔为250 - 500毫秒时，测试脉冲串诱发的群体锋电位幅度小于条件刺激诱发的群体锋电位幅度。选择性阻断s-IPSP的加拉明，减少了刺激间隔在250 - 500毫秒时出现的测试锋电位的抑制。选择性阻断s-EPSP的哌仑西平，减少了刺激间隔大于1000毫秒时出现的测试节后锋电位的晚期易化。非选择性毒蕈碱拮抗剂樟柳碱产生的节后锋电位幅度变化类似于加拉明和哌仑西平的联合作用。证据表明，s-IPSP和s-EPSP改变了神经节神经元的兴奋性状态以及随后通过烟碱型受体介导的突触传递。
