Mechanism of action of cholecystokinin on intestinal blood flow; interactions with opioid peptides and vasoactive intestinal peptide.
The effects of local administration of CCK-OP on mesenteric blood flow was studied in anaesthetized dogs using an electromagnetic flowmeter and interactions with the opioid peptides and VIP examined. CCK-OP was found to enhance enteral blood flow and tissue metabolism. Investigations with pharmacological antagonists showed that the vasoregulatory effect was exerted neurogenically, by influencing the activities of sympathetic alpha 2 adrenergic, dopaminergic, cholinergic, muscarinergic and nicotinic neurones. The flow-increasing action of CCK-OP was enhanced by D-Met2-NleS5-enkephalinamide; the effect was additive and partially blocked by naloxone. D-Met2-Pro5-enkephalinamide blocked the increases caused by CCK-OP in blood flow and tissue acetylcholine levels. The blockade was not competitive and could be totally eliminated by naloxone. VIP blocked the flow-increasing effect of CCK-OP by a non-competitive mechanism. The results provide data on the peptidergic regulatory mechanisms of the mesenteric circulation.
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology*; D004285:Dogs; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000494:pharmacology; D005260:Female; D006207:Half-Life; D007421:Intestine, Small / Q000098:blood supply* / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D012844:Sincalide / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects
D004723:Endorphins; D007773:Lactates; D019344:Lactic Acid; D009270:Naloxone; D014660:Vasoactive Intestinal Peptide; D004744:Enkephalin, Methionine; D002766:Cholecystokinin; D012844:Sincalide; D000109:Acetylcholine; D009638:Norepinephrine