BLOCKING EFFECT OF L-ARGININE ON RETINAL GAP-JUNCTIONS BY ACTIVATING GUANYLATE-CYCLASE VIA GENERATION OF NITRIC-OXIDE

Intracellular application of L-arginine, the precursor of nitric oxide (NO), for horizontal cells of the carp retina blocked dye-coupling of Lucifer Yellow CH among horizontal cells. Injection of NO synthase in hibitor, N(G)-monomethyl-L-arginine or N(G)-nitro-L-arginine, into hor izontal cells suppressed the effects of L-arginine on the cells. Injec tion of guanylate cyclase inhibitor, methylene blue or cystamine, also suppressed the effects of L-arginine. These results suggest that NO, converted from L-arginine by NO synthase, blocked gap junctions betwee n horizontal cells by activating soluble guanylate cyclase to increase cyclic GMP.