AMPLITUDE FLUCTUATIONS IN SYNAPTIC POTENTIALS-EVOKED IN CAT SPINAL MOTONEURONES AT IDENTIFIED GROUP-IA SYNAPSES
AMPLITUDE FLUCTUATIONS IN SYNAPTIC POTENTIALS-EVOKED IN CAT SPINAL MOTONEURONES AT IDENTIFIED GROUP-IA SYNAPSES
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DOI：
10.1113/jphysiol.1983.sp014885
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发表时间：
1983-01-01
影响因子：
5.5
通讯作者：
WALMSLEY, B
中科院分区：
文献类型：
--
作者：
REDMAN, S;WALMSLEY, B
在麻醉猫的脊髓运动神经元中，单组Ia轴突脉冲诱发兴奋性突触后电位（EPSP）。随后重建了产生每个EPSP的Ia轴突-运动神经元连接的形态学细节。在考虑记录噪声的情况下，采用反褶积方法确定了每个EPSP峰幅值的波动模式。对4种EPSP进行分析。一个没有振幅波动；其他的在离散的振幅之间波动，这些振幅被量子增量分开。为了产生每个EPSP的最大峰值振幅，必须增加的增量数总是小于或等于产生EPSP的连接中的突触钮扣数。结果与每个突触钮扣的全或无传递方式假说一致。与运动神经元连接的Ia轴突末端的不同钮扣具有不同的释放递质的概率，在低刺激率下，这种概率有时为零。被诱发的EPSP的离散振幅是由断断续续的传输产生的，以全或无的方式，在一些或所有的终端按钮上得到支持。
Excitatory post-synaptic potentials (EPSP) were evoked in spinal motoneurons (of anesthetized cats) by impulses in single group Ia axons. The morphological details of the Ia axons-motoneuron connection involved in generating each EPSP were subsequently rconstructed. The fluctuation pattern of the peak amplitude of each EPSP was determined using a deconvolution method, taking into account the recording noise. Four EPSP were analyzed. One did not fluctuate in amplitude; the others fluctuated betwen discrete amplitudes which were separated by quantal increments. The number of increments which must be added to produce the largest peak amplitude of each EPSP was always less than, or equal to, the number of synaptic boutons in the connection at which the EPSP was generated. The results are consistent with the all-or-none transmission manner hypothesis at each synaptic bouton. Different boutons in the termination of a Ia axon with a motoneuron have different probabilities of releasing transmitter, and this probability is sometimes zero at low stimulation rates. The idea that the discrete amplitudes of an evoked EPSP result from intermittent transmission, in an all-or-none manner, at some or all of the boutons in the termination is supported.