Mechanism of the potentiation of vasoconstriction by neuropeptide Y in arterioles from the submucosa of the guinea-pig small intestine.
1. Neuropeptide Y (NPY; 3-100 nmol/L) caused a concentration-dependent potentiation of constriction in response to noradrenaline or the thromboxane mimetic U46619 in arterioles from the submucosa of the guinea-pig small intestine. 2. In arterioles permeabilized by exposure to the alpha-toxin of Staphylococcus aureus and maintained in Ca(2+)-buffered medium, NPY potentiated the contractile effects of Ca2+. The magnitude of the potentiation was the same as in intact arterioles. 3. Exposure of arterioles to 1 mumol/L nifedipine to inhibit Ca2+ influx or to 20 mumol/L cyclopiazonic acid to abolish Ca2+ uptake into internal stores had no effect on the potentiating action of NPY.
Neild
T
T
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Xia
J
J
D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D007421:Intestine, Small / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009478:Neuropeptide Y / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
D002121:Calcium Channel Blockers; D009478:Neuropeptide Y; D009543:Nifedipine; D002118:Calcium