Zhang D Q, Yang X L
Shanghai Institute of Physiology, Laboratory of Neurobiology, Chinese Academy of Sciences.
Sheng Li Xue Bao. 1997 Dec;49(6):639-43.
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 hyperpolarization 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.
在灌注的离体鲤鱼视网膜中，对水平细胞进行细胞内记录，并研究了γ-氨基丁酸（GABA）对由视杆和视锥细胞驱动的水平细胞的影响。浴槽施加的GABA（0.5 - 5 mmol/L）导致暗膜电位超极化，并抑制L型视锥水平细胞的光反应。在10个测试细胞中的7个中，GABA的作用被GABAA受体拮抗剂荷包牡丹碱完全阻断。在存在0.5 mmol/L Co2+的情况下，2 mmol/L GABA在12个细胞中的8个中未引起暗膜电位的任何变化，但在其他4个细胞中引起轻微去极化。这些结果表明，在大多数L型视锥水平细胞中，GABA的作用可能由视锥终末上的GABAA受体介导。GABA对视杆水平细胞无作用。
