GABA对鲫鱼视网膜视锥水平细胞的选择性压抑  

THE SELECTIVE SUPPRESSION OF GABA ON CONE-DRIVEN HORIZONTAL CELLS IN CARP RETINA

作　　者：张道启[1] 杨雄里[1] 

机构地区：[1]中国科学院上海生理研究所

出　　处：《生理学报》1997年第6期639-643,共5页Acta Physiologica Sinica

基　　金：国家自然科学基金!39670253;上海生命科学中心资助

摘　　要：本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（05～5mmol／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；GABAA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CO2+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。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 Co2+, 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.

关 键 词：鲫鱼 Γ氨基丁酸 视网膜水平细胞 

分 类 号：Q959.468[生物学—动物学]