Potier B, Dutar P, Lamour Y
Laboratoire de Physiopharmacologie du Système Nerveux, INSERM U161, Paris, France.
Brain Res. 1993 Jul 9;616(1-2):236-41. doi: 10.1016/0006-8993(93)90214-8.
The nature of the coupling mechanism of presynaptic calcium channels involved in the release of neurotransmitters in the mammalian central nervous system is unknown. Using intracellular recordings from CA1 neurons in the rat hippocampal slice preparation, we show that the N-type calcium channels antagonist omega-conotoxin GVIA (omega-CgTx) blocks partially the excitatory (EPSP) and totally the inhibitory (IPSP) synaptic transmission in CA1 hippocampal pyramidal neurons. In addition, the inhibitory effect of omega-CgTx on IPSPs is strongly depressed by intrahippocampal injection of PTX, while the effect on EPSP is not. The results suggest that the nature or the regulation of calcium channels might be different, depending on the location of these channels on excitatory or inhibitory terminals.
哺乳动物中枢神经系统中参与神经递质释放的突触前钙通道的偶联机制的本质尚不清楚。利用大鼠海马脑片制备中CA1神经元的细胞内记录，我们发现N型钙通道拮抗剂ω-芋螺毒素GVIA（ω-CgTx）部分阻断CA1海马锥体神经元的兴奋性（EPSP）突触传递，并完全阻断抑制性（IPSP）突触传递。此外，海马内注射PTX可强烈抑制ω-CgTx对IPSPs的抑制作用，而对EPSP的作用则无影响。结果表明，钙通道的性质或调节可能因这些通道在兴奋性或抑制性终末的位置不同而有所差异。
