Neuropeptide Y increases force development through a mechanism that involves calcium entry in resistance arteries.
The hypothesis that neuropeptide Y (NPY) potentiates noradrenaline (NA)-induced vascular force development by increasing free intracellular Ca2+ ([Ca2+]i) was tested in rat mesenteric resistance arteries. NPY (100 nM) alone was not able to increase either the contraction or [Ca2+]i. However, pretreatment of mesenteric resistance arteries with 100 nM NPY potentiated both [Ca2+]i and active stress induced by 1.5 microM NA. Addition of 100 nM NPY to vessels that had been precontracted with NA (1.5 microM) elicited a large increase in [Ca2+]i and an increase in active stress development. In Ca(2+)-free medium containing 2 mM ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid, the potentiating effect of NPY on the NA-induced contraction was prevented, and readdition of Ca2+ resulted in a large increase in both [Ca2+]i and active stress development. It is concluded that NPY potentiates NA-induced contraction in the isolated mesenteric resistance artery by inducing a rise in [Ca2+]i through an influx of Ca2 from the extracellular source.
Andriantsitohaina
R
R
Laboratoire de Pharmacologie Cellulaire et Moléculaire, Université Louis-Pasteur de Strasbourg, Faculté de Pharmacie, Illkirch, France.
Bian
K
K
Stoclet
J C
JC
Bukoski
R D
RD
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004357:Drug Synergism; D004533:Egtazic Acid / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D014655:Vascular Resistance / Q000187:drug effects*
D009478:Neuropeptide Y; D004533:Egtazic Acid; D002118:Calcium; D009638:Norepinephrine