SYNERGISM AT CENTRAL SYNAPSES DUE TO LATERAL DIFFUSION OF TRANSMITTER
SYNERGISM AT CENTRAL SYNAPSES DUE TO LATERAL DIFFUSION OF TRANSMITTER
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DOI：
10.1073/pnas.85.22.8708
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发表时间：
1988-11-01
影响因子：
11.1
通讯作者：
KORN, H
中科院分区：
文献类型：
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作者：
FABER, DS;KORN, H
金鱼(Carassius Auratus)Mauthner细胞中抑制性突触后电流的记录显示，当相邻突触被共同激活时，存在非线性相互作用。由单个突触前神经元引起的反应与由有限的相似抑制细胞池激活所引起的反应成对。在大约50%的实验中，复合电流大大大于它们各自分量的总和。当两种反应几乎同时发生时，增强作用最大，其衰减与条件化电流的衰减平行；它始于约300µs的延迟，计算表明，在这段时间内，递质分子将横向扩散0.5-1.1µm，相当于相邻突触的间隔。离子电泳法应用甘氨酸对第八神经诱发的抑制电流产生类似的增强作用。当模拟量子抑制反应时，考虑到甘氨酸扩散、递质-受体相互作用和通道激活，后者需要两个结合步骤，结果表明，当相邻输入活跃时，促进作用是由于甘氨酸递质横向扩散到边缘区域，在那里单个结合受体可用于进一步相互作用和通道开放。
Recordings of inhibitory postsynaptic currents in the goldfish (Carassius auratus) Mauthner cell demonstrate nonlinear interactions when adjacent synapses are coactivated. Responses evoked by single presynaptic neurons were paired with those due to activation of a limited pool of similar inhibitory cells. In about 50% of the experiments the compound currents were substantially larger than the sum of their individual components. Potentiation was maximal when the two responses occurred nearly simultaneously, and its decay paralleled that of the conditioning current; it started with a delay of about 300 .mu.sec, and calculations indicate that in this time transmitter molecules would diffuse laterally 0.5-1.1 .mu.m, which equal the separation of adjacent synapses. Iontophoretically applied glycine produced a comparable enhancement of the eighth nerve evoked inhibitory current. When quantal inhibitory responses were simulated, taking into consideration glycine diffusion, transmitter-receptor interactions, and channel activation, with the latter requiring two binding steps, the results demonstrated that the facilitation when neighboring inputs are active is due to lateral diffusion of the transmitter, glycine, to fringe areas where single bound receptors are available for further interactions and channel opening.