Enhancement by nitric oxide of neurogenic contraction in the mouse urinary bladder

In isolated detrusor strips from the mouse urinary bladder, contractile responses to electrical field stimulation were mostly mediated by neurally released acetylcholine and ATP. The aim of this study is to investigate the possible role of nitric oxide (NO) involved in the neurogenic detrusor contraction. Repetitive electrical field stimulation evoked muscle contractions of the isolated mouse detrusor strips, which could be abolished by tetrodotoxin (TTX). NO donors including sodium nitroprusside (SNP) and S-nitroso-N-acetyl-penicillamine (SNAP) as well as exogenous NO increased, while hemoglobin and NO synthase inhibitor N^G-nitro-L-arginine decreased the neurogenic detrusor contractions. The addition of L-arginine reversed the inhibitory effect of N^G-nitro-L-arginine. SNP failed to affect the contractions induced by carbachol and α,β-methylene ATP. These findings suggest that NO potentiated the excitatory neuromuscular transmission in electrically stimulated detrusor strips from the mouse. Received: 15 July 1997 / Accepted: 4 September 1997