Involvement of Nitric Oxide From Nerves on Diarrhea Induced by Castor Oil in Rats

Abstract

Nitric oxide(NO)is involved in the mechanism of castor oil-induced diarrhea.This study was performed to elucidate the source of NO.Diarrhea was induced by oral administration of castor oil in rats.Diarrhea was significantly inhibited by the pre-treatment with a relatively selective nerve NO synthase inhibitor, 7-nitroindazole.This effect was attenuated by the treatment with L-arginine.Capsaicin-sensitive afferent nerve degeneration did not affect the diarrhea.N^G-Nitro-L-arginine methylester significantly inhibited diarrhea even in capsaicin-pretreated rats.These data suggest, a least in part, the involvement of NO from nerves on the diarrhea induced by castor oil in rats.