Strong synergism between GABAA and glycine receptors on isolated carp third-order neurons

A strong synergistic interaction between the bicuculline-sensitive GABA receptor (GABA(A) receptor) and the strychnine-sensitive glycine receptor was observed in third-order neurons acutely isolated from crucian carp retina, with the use of the whole-cell patch-clamp recording technique. In 58 of 153 cells, 10 mu M GABA or glycine separately applied to amacrine/ganglion cells failed to induce any responses or only induced small currents (<20 pA), while co-application of these two chemicals resulted in much larger responses (403.05 +/- 319.98 pA). The current induced by the co-application was mediated by chloride channels, and both GABA(A) and glycine receptors were involved in the potentiation. The underlying mechanisms of this interaction and its possible physiological role are discussed. (C) 1998 Lippincott Williams & Wilkins.