GABA modulates color-opponent bipolar cells in carp retina.
In the present work, the effects of gamma-aminobutyric acid (GABA) were examined while recording intracellularly from color-opponent bipolar cells in the isolated, superfused carp retina. Bath-applied GABA differentially suppressed light responses of R/G cells, which depolarized and hyperpolarized, respectively, in response to red and green flashes, and G/R cells, which showed the opposite responses. In either R/G or G/R cells, the response driven by input from red cones was invariably suppressed to a greater extent. Such effects of GABA were completely blocked by picrotoxin, but only partially by bicuculline, suggesting that the GABAC receptor, in addition to the GABAA receptor, may also be involved. It is postulated that GABA modulates the color-opponent bipolar cells either through activating GABA receptors on these cells directly or those on cone terminals indirectly.
Zhang
D Q
DQ
Shanghai Institute of Physiology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China.
Yang
X L
XL
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003118:Color Perception / Q000502:physiology*; D004594:Electrophysiology; D018756:GABA Antagonists / Q000494:pharmacology; D006054:Goldfish; D010852:Picrotoxin / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000502:physiology; D012160:Retina / Q000737:chemistry* / Q000166:cytology* / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D001640:Bicuculline; D018756:GABA Antagonists; D010852:Picrotoxin; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid