Ohno-Shosaku T, Hirata K, Sawada S, Yamamoto C
Department of Physiology, Faculty of Medicine, Kanazawa University, Ishikawa, Japan.
Neurosci Lett. 1994 Nov 7;181(1-2):145-8. doi: 10.1016/0304-3940(94)90580-0.
Effects of Ca2+ channel blockers on GABAergic transmission were examined with rat cultured hippocampal neurons. The GABAergic synaptic currents (IPSCs) evoked by electrical stimulation of single presynaptic neurons were recorded from voltage-clamped postsynaptic neurons. The amplitude of IPSCs was not changed by 10 microM nifedipine (L-type Ca2+ channel blocker), but was decreased irreversibly to 37% of control by 1 microM omega-conotoxin GVIA (N-type blocker, CgTX), to 67% by 0.1 microM omega-agatoxin IVA (P-type blocker, AGTX), and to 1% by both toxins. From these data and the Ca(2+)-dependence of IPSCs, the contributions of CgTX-sensitive and AGTX-sensitive Ca2+ channels to the transmission were estimated at 59% and 36%, respectively.
利用大鼠海马神经元培养物研究了钙通道阻滞剂对γ-氨基丁酸（GABA）能传递的影响。从电压钳制的突触后神经元记录由单个突触前神经元电刺激诱发的GABA能突触电流（IPSCs）。10微摩尔硝苯地平（L型钙通道阻滞剂）未改变IPSCs的幅度，但1微摩尔ω-芋螺毒素GVIA（N型阻滞剂，CgTX）使其不可逆地降至对照的37%，0.1微摩尔ω-阿加毒素IVA（P型阻滞剂，AGTX）使其降至67%，两种毒素共同作用使其降至1%。根据这些数据以及IPSCs对钙的依赖性，估计CgTX敏感和AGTX敏感的钙通道对传递的贡献分别为59%和36%。
