Biliary motility associated with gallbladder storage and duodenal delivery of canine hepatic biliary output

Abstract

Hepatic biliary output may be stored in the gallbladder (GB) or delivered into the duodenum. The role of the GB and sphincter of Oddi (SO) in the partition of hepatic biliary output between GB and duodenum was studied in 6 dogs during the interdigestive and postprandial periods. Three animals received a continuous intravenous infusion of [14C]taurocholic acid, which served as a marker of the steady-state hepatic output of radiolabeled bile acid. Gallbladder filling and emptying and duodenal delivery of [14C]taurocholic acid were determined using duodenal marker perfusion to measure output. Sphincter of Oddi, common duct, GB, and duodenal manometry was performed in 3 additional dogs. During fasting, partial GB emptying and an increased rate of duodenal delivery occurred between 60% and 90% of each cycle of the migrating motor complex. The majority of hepatic taurocholic acid output was stored in the GB during the first half of the migrating myoelectric complex. However, in the latter half of the migrating myoelectric complex, the frequency of SO contractions and basal SO pressure decreased, GB pressure increased, net partial GB emptying occurred, and peak rates of duodenal taurocholic acid delivery were achieved. Feeding induced immediate decreases in basal SO pressure and frequency of phasic contractions, and an immediate increase of GB pressure. Gallbladder emptying and duodenal taurocholic acid delivery were maximal in the first 10 min after feeding. Thus, both the cyclic interdigestive and immediate postprandial increases in duodenal bile acid delivery are associated with SO relaxation and GB contraction. The immediate postprandial changes in SO and GB motility, and in duodenal bile acid output, suggest a cephalic phase of postprandial duodenal bile acid delivery.