Medycyna Wet. 63 (1), 44-46, 2007
Romański K.
Bile acids and motor activity of the stomach and the small intestine
Bile acids exhibit detergent properties. Their influence on various types of cells in the gastrointestinal wall, including smooth muscle cell, is substantial. They are present in the intestinal lumen and circulation as conjugated or deconjugated salts. In studies in vitro they cause smooth muscle relaxations. Their effects in vivo can be due to their direct action on the smooth muscles or they act indirectly: the action can be mediated by the nervous system and gut hormone release. When the gastrointestinal mucosa is exposed to bile or bile acids the frequency of gastric contractions increases and the activity front of the migrating motor complex (MMC) is initiated. Bile acids exert a stronger effect than the entire bile. The type and amount of bile acids can also be important. The intraarterial route of bile acid administration appears to be more efficient than intraluminal route. Bile diversion from the duodenum induces contrary effects, i.e. a relaxing effect in the stomach and irregular motor activity in the small bowel or prolonged phase 2 MMC have been observed. These effects are apparently due to the interaction of bile acids with muscarinic receptors and mediated by motilin and cholecystokinin, two gut hormones the release of which is strongly influenced by luminal bile acids.
Keywords: bile acids