Both N^G-monomethyl-L-arginine (1.0×10^-5mol/kg), which is the specific inhibitor of nitric oxide formation, and D-arginine (1.0×10^-4mol/kg) or L-arginine (1.0×10^-4mol/kg) were administered intravenously to albino rabbits under local anesthesia, and choroidal blood flow was measured by the hydrogen clearance method until 60 minutes after administration.
The effect of N^G-monomethyl-L-arginine, which caused vasoconstriction of the choroid, was partially reversed by the addition of L-arginine. These findings suggest that the endothelium-derived relaxing factor from L-arginine participates in the regulation of choroidal blood flow.