Effect of truncal vagotomy on sphincter of oddi cyclic motility in conscious dogs.

OBJECTIVE

To evaluate the effects of truncal vagotomy at the diaphragmatic level on the sphincter of Oddi (SO) motility.

SUMMARY BACKGROUND DATA

Cholelithiasis is a well-known late complication after gastrectomy and/or vagotomy. The mechanism of gallstone formation is only partly understood, and few studies address the effects of vagotomy on SO cyclic motility in conscious subjects.

METHODS

In conscious dogs, SO motility was recorded by retrograde infusion manometry through a duodenal cannula before and after bilateral truncal vagotomy at the diaphragmatic level. Effects of cholecystokinin-octapeptide and feeding were also evaluated before and after vagotomy.

RESULTS

SO cyclic motility and the gastroduodenal migrating motor complex continued to occur during postvagotomy fasting. Intermittent inhibitions of the SO and duodenal contractions disappeared during phase 3 of the migrating motor complex. SO basal pressure significantly decreased, whereas the amplitude significantly increased. Cholecystokinin-octapeptide inhibited SO contractions before and after vagotomy. The amplitude of SO contractions increased and their frequency decreased after feeding; however, these effects disappeared after vagotomy.

CONCLUSIONS

SO cyclic motility and the effects of feeding change after truncal vagotomy at the diaphragmatic level. These facts may at least partly explain gallstone formation after gastric surgery and/or vagotomy.