[Bile acids and electric activity of the stomach and small intestine in dogs during the interdigestive period].

Examinations were carried out on 4 fasted dogs using chronic experimental model. In the animals the functional cholecystectomy was performed, 2 cannulas were inserted into the common bile duct and 9 pairs of electrodes were ++implanted from pyloric antrum till ileum. After the disconnection of the exteriorized tubes enterohepatic circulation of bile acid was interrupted. Then, sodium salts of taurocholic, taurodeoxycholic and taurochenodeoxycholic acids (at the concentrations 5, 20 and 50 mM) alone and in the combination were infused intraduodenally and myoelectric activity was continuously recorded. During control experiments the enterohepatic circulation was preserved. Application of individual bile acids at higher concentrations and their combinations caused significant (about 60 min) prolongation of cycle intervals changing fundamentally duration of both phases I and II along with the alteration of their relative proportion. In the control group duration, of both phase I and II as measured in mid jejunum lasted 47 +/- 3 and 38 +/- 2 min, respectively (ratio 1.24). During administration of 50 mM Na-taurodeoxycholate these values were respectively equal to 6 +/- 2 (P less than 0.01) and 122 +/- 31 min (P less than 0.05), respectively, and the ratio was 0.05. Infusions of primary bile acids resulted in the greater percentage of phases III which originated from the stomach. Propagation velocity of phase III as measured in the jejunum was about 50-100% faster, mainly during the infusion of dihydroxy bile acids. The results have suggested that bile acids are responsible for majority of alterations of the myoelectric cycle induced by intraduodenal bile administration. These changes could be interpreted as the disappearing tendency of the cycle but their mechanisms still remain to be elucidated.