Neural control of the canine pylorus.
After atropine administration the anesthetized dog exhibits significant spontaneous pyloric contractile activity and an inhibition-relaxation response upon electrical vagal stimulation. This inhibition-relaxation response was completely blocked by tetrodotoxin administration and by transection of the intraabdominal vagal nerves. In addition, tetrodotoxin administration caused a dramatic increase in spontaneous pyloric motor activity. The histaminergic receptor antagonists diphenhydramine and cimetidine did not block the inhibition-relaxation response. The octapeptide of cholecystokinin (CCK-OP) caused a dose-dependent increase in antral and pyloric motor activity which was significantly decreased by atropine administration. Therefore, histamine and CCK do not appear to play a significant role in the vagally mediated inhibition-relaxation response of the canine pylorus or in the atropine-resistant spontaneous pyloric motor activity.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001340:Autonomic Nerve Block; D002766:Cholecystokinin / Q000494:pharmacology; D004285:Dogs; D004386:Duodenum / Q000294:innervation; D004558:Electric Stimulation; D005769:Gastrointestinal Motility / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology; D011706:Pyloric Antrum / Q000294:innervation; D011708:Pylorus / Q000294:innervation*; D013779:Tetrodotoxin / Q000494:pharmacology; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
D013779:Tetrodotoxin; D001285:Atropine; D006632:Histamine; D002766:Cholecystokinin