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GABA对鲫鱼视网膜视锥水平细胞的选择性压抑

张道启, 杨雄里

中国科学院上海生理研究所, 中国科学院神经生物学开放实验室. 上海 200031

摘要

该工作应用细胞内记录技术，在灌流的鲫鱼视网膜的标本上，研究了γ-氨基丁酸(GABA)对视杆水平细胞和视锥水平细胞的影响。结果表明，在GABA(0.5～5mmol/L)的作用下，L型视锥水平细胞暗中膜电位超极化，对光反应减小；GABA_(A)受体的特异性拮抗剂荷包牡丹碱在70％的细胞上能阻断上述GABA的效应。进而，在用CO~(2+)阻断光感受器至水平细胞的突触前输入后再施加GABA，60％的L型水平细胞膜电位无变化，提示GABA的作用主要由位于视锥终末上的GABAA受体介导。GABA对视杆水平细胞的膜电位和光反应均无明显影响。

关键词： GABA; 视网膜水平细胞; 突触传递; GABA_(A)受体

The selective suppression of gaba on cone-driven horizontal cells in carp retina

Zhang Daoqi, Yang Xiongli

Shanghai Institute of Physiology, Laboratory of Neurobiology, Chinese Academy of Sciences. Shanghai 200031, China

Abstract

Intracellular recordings were made from horizontal cells in the superfused, isolated carp retina and effects of GABA on rod- and cone-driven horizontal cells were studied.Bath-applied GABA (0.5～5 mmol/L) resulted in a hrperpolarization of dark membrane potential and a suppression of light responses of L-type cone horizontal cells. In 7 out of 10 cells tested the effects of GABA were completely blocked by bicuculline, an antagonist of GABAA receptors. In the presence of 0.5 mmol/L Co~(2+), 2 mmol/L GABA could not induce any change in dark membrane potential in 8 out of 12 cells, but cause slight depolarization in other 4 cells. These results suggest that the GABA effects may be mediated by GABAA receptors on cone terminals in the majority of the L-type cone horizontal cells. GABA had no effect on rod horizontal cells.

Key words: GABA;Retinal horizontal cell;Synaptic transmission;GABA_(A) receptor

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引用本文：

张道启, 杨雄里. GABA对鲫鱼视网膜视锥水平细胞的选择性压抑[J]. 生理学报 1997; 49 (6): .

Zhang Daoqi, Yang Xiongli. The selective suppression of gaba on cone-driven horizontal cells in carp retina. Acta Physiol Sin 1997; 49 (6): (in Chinese with English abstract).