Inhibitory effects of 1-iodo-3-aminomethyl-5,6,7,8-tetrahydro-2-naphthol (ONO-3122) and prostaglandin H2 on vasopressin-induced osmotic water flow in toad bladder

Summary Both 1-iodo-3-aminomethyl-5,6,7,8-tetrahydro-2-naphthol (ONO-3122), which increases endogenous PGH₂, and PGH₂ itself, significantly depressed vasopressin-induced osmotic water flow in the toad bladder. These results suggest that ONO-3122 increases endogenous PGH₂ synthesis, and that PGH₂ and/or its metabolites inhibit vasopressin-induced water flow.I am grateful to Mr Y. Nara and Mrs S. Sugawara for their excellent technical assistance. This work supported in part by grant from the Life Science Laboratories.