Relaxant effect of capsaicin in the rat gastric fundus.
The effect of capsaicin was studied in precontracted longitudinal muscle strips of the rat gastric fundus. Capsaicin induced a relaxation in the concentration range 10(-7)-10(-6) M. The relaxation induced by 10(-6) M capsaicin was completely prevented by extrinsic denervation of the stomach. The adrenoceptor antagonists phentolamine and propranolol did not influence the effect of capsaicin while hexamethonium potentiated it; this potentiation was not observed with another nicotinic receptor antagonist trimethaphan. Tetrodotoxin did not have a consistent effect as it reduced the capsaicin-induced relaxation in some but not all tissues. The peptidase trypsin consistently reduced the action of capsaicin but vasoactive intestinal polypeptide (VIP) antiserum, desensitization to calcitonin gene-related peptide (CGRP), and CGRP antiserum had no influence. The neuropeptide involved in the relaxant effect of capsaicin in the rat gastric fundus has thus still to be determined.
Heymans Institute of Pharmacology, University of Gent Medical School, Belgium.
R A
RA
Lefebvre
F A
FA
De Beurme
S
S
Sas
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002211:Capsaicin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D005748:Gastric Fundus / Q000187:drug effects*; D018738:Hexamethonium; D006584:Hexamethonium Compounds / Q000494:pharmacology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009475:Neurons, Afferent / Q000502:physiology; D009479:Neuropeptides / Q000494:pharmacology / Q000502:physiology; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology; D014357:Trypsin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D006584:Hexamethonium Compounds; D009479:Neuropeptides; D014660:Vasoactive Intestinal Peptide; D018738:Hexamethonium; D013779:Tetrodotoxin; D014357:Trypsin; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin