Related Experiment Video
Updated: Jul 18, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
Published on: June 18, 2012
Involvement of nitric oxide in the response to 5-hydroxytryptamine in the rat in-vivo
C M Franks1, J Hardcastle, P T Hardcastle
1Department of Biomedical Science, Sheffield University, UK.
Abstract:
The involvement of nitric oxide (NO) in the effects of 5-HT on intestinal secretion and cardiovascular function in anaesthetized rats was investigated using NG-nitro-L-arginine methyl ester (L-NAME), a specific NO-synthase antagonist, and its optical isomer D-NAME. L-NAME significantly reduced the prolonged hypotensive response to 5-HT. It also caused a small rightward shift in the colonic 5-HT dose-response curve. This suggests that NO plays a significant role in the prolonged hypotensive response to 5-HT, and may make a small contribution to the secretory response of the colon, but not that of the jejunum, in the rat in-vivo.

