Rat exocrine pancreatic secretion by vagal stimulation occurs via multiple mediators.
The vagus is a mixed nerve containing cholinerrgic and non-cholinergic neurons. Vagal fibers interact with peptidergic neurons of the enteric nervous system which stain immunohistochemically for cholecystokinin, vasoactive intestinal polypeptide, and gastrin releasing peptide. The contribution of these peptidergic neurons in the pancreatic response to vagal stimulation is unknown. We tested the effect of specific inhibitor of these stimulants against vagally mediated exocrine secretion in rats. The response to vagal stimulation was blocked significantly by each of the following: the ganglionic blocker hexamethonium (100% inhibition); the muscarinic, cholinergic blocker atropine (85% inhibition); the specific cholecystokinin-A receptor blocker (91% inhibition); and a vasoactive intestinal polypeptide polyclonal antibody (89% inhibition). This observation is consistent with the hypothesis that potentiating interactions among several agonists mediate the vagal response. Our study, however, dose not exclude acetylcholine as the final common mediator.
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Department of Surgery, University of California School of Medicine, San Francisco, USA.
Nelson
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D000681:Amylases / Q000378:metabolism; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001570:Benzodiazepinones / Q000494:pharmacology; D020109:Devazepide; D004558:Electric Stimulation; D005730:Ganglionic Blockers / Q000494:pharmacology*; D018738:Hexamethonium / Q000494:pharmacology*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010179:Pancreas / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012844:Sincalide / Q000037:antagonists & inhibitors; D014630:Vagus Nerve / Q000502:physiology*
D001570:Benzodiazepinones; D005730:Ganglionic Blockers; D018727:Muscarinic Antagonists; D018738:Hexamethonium; D001285:Atropine; D000681:Amylases; D020109:Devazepide; D012844:Sincalide