Either N- or P-type calcium channels mediate GABA release at distinct hippocampal inhibitory synapses
Either N- or P-type calcium channels mediate GABA release at distinct hippocampal inhibitory synapses
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DOI：
10.1016/s0896-6273(00)81246-5
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发表时间：
1997-03-01
期刊：
影响因子：
16.2
通讯作者：
Thompson, SM
中科院分区：
文献类型：
--
作者：
Poncer, JC;McKinney, RA;Thompson, SM
大多数中枢突触的递质释放依赖于多种类型的钙通道。由于中间神经元的异质性，海马中介导GABA释放的通道的鉴定变得复杂。在海马切片培养中，从成对的抑制细胞和锥体细胞中记录到单一的IPSPs。N型通道拮抗剂ω-芋螺毒素MVIIA可阻断辐射状棘球蚴中间神经元产生的IPSPs，而P/Q型通道拮抗剂ω-蛇毒毒素IVA则无此作用。相反，ω-蛇曲霉毒素IVA废除了由灵芝和圣奥里恩斯interneurons产生的IPSPs，但ω-芋螺毒素MVIIA没有影响。单一的IPSPs被毒素阻断后，突触前钙离子内流增加不能恢复传递。两种类型的中间神经元的轴突终止于CA 3区的不同层内。因此，GABA释放到锥体细胞，不像谷氨酸释放，完全由N-或P-型钙通道介导，这取决于突触前细胞和突触的突触后位置。
Transmitter release at most central synapses depends on multiple types of calcium channels. Identification of the channels mediating GABA release in hippocampus is complicated by the heterogeneity of interneurons. Unitary IPSPs were recorded from pairs of inhibitory and pyramidal cells in hippocampal slice cultures. The N-type channel antagonist omega-conotoxin MVIIA abolished IPSPs generated by interneurons in st. radiatum, whereas the P/Q-type antagonist omega-agatoxin IVA had no effect. In contrast, omega-agatoxin IVA abolished IPSPs generated by st. lucidum and st. oriens interneurons, but omega-conotoxin MVIIA had no effect. After unitary IPSPs were blocked by toxin, transmission could not be restored by increasing presynaptic calcium entry. The axons of the two types of interneurons terminated within distinct strata of area CA3. Thus, GABA release onto pyramidal cells, unlike glutamate release, is mediated entirely by either N- or P-type calcium channels, depending on the presynaptic cell and the postsynaptic location of the synapse.