Akira Furuichi (1), Noriaki Makimoto (1), Masayuki Ogishimai (2), Kanichirou
Nakao (1), Akihito Enjoji (1), Junichiro Furui (1), Takashi Kanematsu (1)
and Kohtaro Taniyama (2,*)
Departments of (1) Surgery II and (2) Pharmacology, Nagasaki University School of Medicine, Nagasaki 852-8523, Japan
(*) To whom correspondence should be addressed.
Abstract: Intestinal contractility and release of endogenous acetylcholine (ACh) were measured simultaneously in vivo in the small intestine of the anesthetized dog. Electrical stimulation of nerves in the intestinal seromuscular layers caused contractions and increased concentrations of ACh in the dialysate, which were abolished by infusion of tetrodotoxin into the intestinal marginal artery at 75 nmol/ml. Intraarterial administration of atropine at 150 nmol/ml abolished the stimulated contractions, without significant effects on increases in concentrations of dialysate ACh. Thus, the nerve-stimulated contractions were found in vivo to be associated with a local increase in ACh release from the intestinal cholinergic neurons.
Keywords: Intestinal contraction, Acetylcholine release, In vivo microdialysis