Effects of atropine and pirenzepine on sphincter of Oddi motility. A manometric study.

We studied the Oddi sphincter motility by endoscopic manometry in 10 consecutive patients randomized in a double-blind fashion, after i.v. administration of two anticholinergic compounds (0.5 mg atropine sulfate and 10 mg pirenzepine). Pirenzepine significantly decreased the basal sphincteric pressure, as well as the amplitude and frequency of the phasic contractions. The only significant effect of atropine was the modification of the frequency of the phasic contractions, but only for a short period of time. Our results suggest that muscarinic innervation must be present for a normal sphincter of Oddi motility.