[Effect of liver bile on interdigestive electric activity of the stomach and small intestine in dogs].

Utilizing the chronic experimental dog model the effect of intraduodenal administration of bile upon the interdigestive electric activity of the stomach and small intestine was examined. For this purpose the functional cholecystectomy was performed and common bile duct was cannulated with two catheters. Tubes connected over the skin allowed spontaneous bile circulation during control experiments and in between the experimental periods. Nine pairs of electrodes were implanted into the stomach and small intestinal wall for electromyography. During other experiments standard bile was infused intraduodenally at the rate 0.5 ml.min-1 for 300 min and whole hepatic bile was introduced at the rates 2 ml.min-1 for 60 min and 30 ml.min-1 for 2 min. Hepatic bile infusion at the low rate, when started during phase II of the migrating myoelectric complex, induced the premature phase III after 10 +/- 2 min and caused about 20% reduction of cycle duration in the duodenum as compared to control experiments (P less than 0.05). Fast administration of hepatic bile elicited the premature phase III in 8 +/- 2 min, caused 20-30% reduction of the duodeno-jejunal cycle duration (P less than 0.05) in comparison with control group and induced in 26% phase III in the stomach. Cycles were shortened at the expense of markedly decreased duration of phase I; for example in the duodenum phase I was reduced from 30 +/- 3 (control experiments) to 11 +/- 2 min, P less than 0.001. Standard bile infusion exerted less pronounced changes, apart from increasing the propagation velocity of phase III in the first jejunal segment from 6 +/- 0.5 cm.min-1 in control group to 13 +/- 3 cm.min-1, P less than 0.05. In two experiments rapid bile administration evoked an inhibitory response. Results obtained suggest that the luminal bile stimulates the interdigestive electrical activity of the stomach and small bowel of the dog. This stimulatory effect may represent the feedback mechanism preventing the prolonged retention of continuously inflowing bile in a bowel section and, particularly, in the duodenum.