Endoscopic manometry of the sphincter of Oddi in dogs. Pharmacological effects of anticholinergic and selective antimuscarinic agents.

A dog model was used for direct measurement of the sphincter of Oddi using endoscopy. The effects of anticholinergic agents and a selective antimuscarinic agent on the canine sphincter of Oddi motility were studied. Manometric tracing at the canine sphincter showed rhythmical phasic contractions which were not affected by respiration. The mean values of the basal motility were as follows: the peak pressure was 61.5 +/- 2.2 (m +/- SE) cmH2O, trough pressure was 2.18 +/- 1.2 cmH2O, and the frequency was 17.4 +/- 0.2 waves/min. Intravenous administration of atropine sulfate, butropium bromide, butylscopolamine bromide and also pirenzepine significantly reduced the amplitude and frequency of canine sphincter contractions. From these results, it appeared that the cholinergic autonomic nervous system might be the one of the regulators of the canine sphincter of Oddi activity.