title: Effect of intravenous dopamine infusion on intramural blood flow distribution and fluid absorption in the feline small intestine.
abstract: The aim of the study was to investigate the effects of dopamine on the intestinal mucosal blood flow and transport function. Dopamine was infused intravenously at 20 micrograms X kg-1 X min-1 in anesthetized cats. Total and intramural blood flow in an isolated jejunal segment was measured by a combined drop-flow and 85Kr clearance technique. Net fluid transport was recorded by two independent perfusion methods. Unidirectional sodium transport was estimated from luminal 22Na disappearance. Dopamine induced a pronounced mucosal vasodilatation up to 400% of control values. Concomitantly, net fluid and sodium absorption increased by 50%. The effect on sodium transport was due to a pronounced decrease in tissue-to-lumen sodium flux, a pattern similar to the one seen on alpha-adrenergic stimulation. The effect of dopamine on blood flow was unaffected by phentolamine, 1 mg X kg-1, whereas the absorptive response was abolished. The findings indicate that dopamine induces a mucosal vasodilation via one mechanism (possibly dopaminergic) and enhances fluid transport via another mechanism, probably alpha-adrenergic.
mesh_terms: D000818:Animals; D002415:Cats; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007263:Infusions, Parenteral; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000098:blood supply / Q000378:metabolism; D007421:Intestine, Small / Q000098:blood supply* / Q000502:physiology; D008297:Male; D012039:Regional Blood Flow / Q000187:drug effects
chemical_list: D004298:Dopamine