Effects of neuropeptide Y on double-peaked constrictor responses to periarterial nerve stimulation in isolated, perfused canine splenic arteries.
The periarterial electrical nerve stimulation readily induced a double-peaked vasoconstriction in the isolated, perfused canine splenic artery. P2X-Purinoceptors have previously been shown to be involved mainly in the 1st-phase response and alpha 1-adrenoceptors, mostly in the 2nd-one. The dose used of neuropeptide Y (NPY) (0.01-0.1 microM) given into the preparation caused a slight but insignificant vasoconstriction. The treatment with NPY at concentrations of 0.01-0.1 microM produced a parallel inhibition on the 1st- and 2nd-phase responses following nerve stimulation at the frequencies used (1-10 Hz) in a dose-dependent manner. The vasoconstrictor responses to administered ATP (0.01-1 mumol) or noradrenaline (0.03-3 nmol) were slightly but not significantly potentiated by 0.1 microM NPY. The results indicate that NPY predominantly exerts a prejunctionally inhibitory modulation on the purinergic and adrenergic transmission in peripheral sympathetic nerves innervating the canine splenic artery.
Yang
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Department of Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan.
Chiba
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D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D013157:Splenic Artery / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
D009478:Neuropeptide Y; D013779:Tetrodotoxin; D000255:Adenosine Triphosphate; D009638:Norepinephrine