gamma-Aminobutyric acid antagonists decrease junctional communication between L-horizontal cells of the retina.

Abstract

GABA antagonists, bicuculline and picrotoxin, narrowed the receptive field profile of the large field horizontal cell (L1HC) in the turtle retina when added to the perfusion medium in .mu.M concentrations. The coupling resistance between neighboring L1HC was increased by bicuculline or picrotoxin. Under control conditions, the dye Lucifer yellow injected into 1 L1HC diffused into a large number of neighboring L1HC; bicuculline or picrotoxin greatly restricted dye passage between these same cells. Evidently, GABA antagonists decrease the conductance of gap junctions between L1HC.