Selective potentiation of extracellular Ca2+-dependent contraction by neuropeptide Y in rabbit mesenteric arteries.
1. Neuropeptide Y (NPY) potentiated the contractile responses induced by electrical transmural stimulation, noradrenaline and KCl in the rabbit mesenteric artery. 2. In preparations treated with noradrenaline or KCl in Ca2+ free medium, NPY also potentiated the contractile response induced by resupplementation of Ca2+. 3. 3H-efflux from the arteries preincubated with [3H]-noradrenaline was not affected by NPY. 4. These results suggest that NPY selectively acts on the postsynaptic membrane and potentiates the contractions mediated through receptor-operated and voltage-dependent Ca channels.
Oshita
M
M
Department of Pharmacology, Fukui Medical School, Japan.
Kigoshi
S
S
Muramatsu
I
I
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology; D004558:Electric Stimulation; D006145:Guanethidine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits
D015220:Calcium Channels; D009478:Neuropeptide Y; D011189:Potassium Chloride; D003042:Cocaine; D002118:Calcium; D009638:Norepinephrine; D006145:Guanethidine