Granular cells of the mormyrid electrosensory lobe and postsynaptic control over presynaptic spike occurrence and amplitude through an electrical synapse.
Granular cells of the mormyrid electrosensory lobe and postsynaptic control over presynaptic spike occurrence and amplitude through an electrical synapse.
复制标题
斑尾鱼电感觉叶的颗粒细胞和突触后通过电突触控制突触前尖峰的发生和幅度。
DOI：
10.1152/jn.01262.2006
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发表时间：
2007
影响因子：
2.5
通讯作者：
Bell,CurtisC
中科院分区：
文献类型：
--
作者：
Zhang,Jianmei;Han,VictorZ;Meek,Johannes;Bell,CurtisC
Primary afferent fibers from the electroreceptors of mormyrid electric fish use a latency code to signal the intensity of electrical current evoked by the fish's own electric organ discharge (EOD). The afferent fibers terminate centrally in the deep and superficial granular layers of the electrosensory lobe with morphologically mixed chemical–electrical synapses. The granular cells in these layers seem to decode afferent latency through an interaction between primary afferent input and a corollary discharge input associated with the EOD motor command. We studied the physiology of deep and superficial granular cells in a slice preparation with whole cell patch recording and electrical stimulation of afferent fibers. Afferent stimulation evoked large all-or-none electrical excitatory postsynaptic potentials (EPSPs) and large all or none GABAergic inhibitory postsynaptic potentials (IPSPs) in both superficial and deep granular cells. The amplitudes of the electrical EPSPs depended on postsynaptic membrane potential, with maximum amplitudes at membrane potentials between −65 and −110 mV. Hyperpolarization beyond this level resulted in either the abrupt disappearance of EPSPs, a step-like reduction to a smaller EPSP, or a graded reduction in EPSP amplitude. Depolarization to membrane potentials lower than that yielding a maximum caused a linear decrease in EPSP amplitude, with EPSP amplitude reaching 0 mV at potentials between −55 and −40 mV. We suggest that the dependence of EPSP size on postsynaptic membrane potential is caused by close linkage of pre- and postsynaptic membrane potentials through a high-conductance gap junction. We also suggest that this dependence may result in functionally important nonlinear interactions between synaptic inputs.
