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.
Lefebvre
R A
RA
Heymans Institute of Pharmacology, University of Gent Medical School, Belgium.
De Beurme
F A
FA
Sas
S
S
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