Is the CCK-8 induced relaxation of the feline sphincter of Oddi mediated by VIP neurons?
The regional, intraarterial, injection of CCK-8 elicits reciprocal effects on the motility of the extrahepatic biliary tree in the cat: the contraction of the gallbladder and a relaxation of the sphincter of Oddi as well as of the duodenal wall. After neural blockade with tetrodotoxin the responses of the sphincter to CCK-8 were blocked, and the responses of the gallbladder were markedly reduced. After the regional administration of a VIP antiserum the sphincter relaxation in response to CCK-8 was blocked. Immunocytochemically it was demonstrated that the feline sphincter contains a rich VIP-ergic innervation, while CCK-like immunoreactivity was found only in mucosal endocrine cells. The results indicate that CCK-8 selectively activates inhibitory VIP neurons innervating the sphincter. After the administration of a nonpeptide CCK-receptor antagonist, the CCK-8 induced motor responses of both the sphincter and the gallbladder were markedly reduced. This indicates that blockade of CCK-8 receptors involves muscular as well as neural CCK-receptors.
Dahlstrand
C
C
Department of Surgery, University of Göteborg, Sweden.
Dahlström
A
A
Theodorsson
E
E
Rehfeld
J
J
Ahlman
H
H
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002415:Cats; D020109:Devazepide; D005260:Female; D007106:Immune Sera / Q000276:immunology; D007150:Immunohistochemistry; D008297:Male; D009126:Muscle Relaxation; D009407:Nerve Block; D009474:Neurons / Q000502:physiology*; D012844:Sincalide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009803:Sphincter of Oddi / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*
D001570:Benzodiazepinones; D007106:Immune Sera; D014660:Vasoactive Intestinal Peptide; D013779:Tetrodotoxin; D020109:Devazepide; D012844:Sincalide