The effect of strychnine, bicuculline, and picrotoxin on X and Y cells in the cat retina.
The effect of intravenous strychnine and the GABA antagonists picrotoxin and bicuculline upon the discharge pattern of center-surround-organized cat retinal ganglion cells of X and Y type were studied. Stimuli (mostly scotopic, and some photopic) were selected such that responses from both on and off-center cells were either due to the center, due to the surround, or clearly mixed. Pre-drug control responses were obtained, and their behavior following administration of the antagonists was observed for periods up to several hours. X-cell responses were affected in a consistent manner by strychnine while being unaffected by GABA antagonists. All observed changes following strychnine were consistent with a shift in center-surround balance of X cells in favor of the center. For Y-cell responses to flashing annuli following strychnine, there was either no shift or a relatively small shift in center-surround balance. Compared to X-cell responses to flashing lights, those of Y cells were very little affected by strychnine and in most cases were unaffected. It thus appears that glycine plays a similar role in receptive field organization of X cells as does GABA in Y cells (Kirby and Enroth-Cugell, 1976. J. Gen. Physiol. 68:465-484).
D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology*; D002415:Cats; D008027:Light; D010852:Picrotoxin / Q000494:pharmacology*; D012160:Retina / Q000166:cytology / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology*
D001640:Bicuculline; D010852:Picrotoxin; D013331:Strychnine