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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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Citing This Article：

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).