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PRE‐AND POSTJUNCTIONAL EFFECTS OF NEUROPEPTIDE Y ON THE RABBIT ISOLATED EAR ARTERY
Author(s) -
WongDusting H. K.,
Rand M. J.
Publication year - 1988
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1988.tb01094.x
Subject(s) - neuropeptide y receptor , endocrinology , medicine , stimulation , human ear , chemistry , neuropeptide , free nerve ending , nerve stimulation , norepinephrine , artery , biology , receptor , dopamine , physics , acoustics
b 1. In the isolated perfused and superfused rabbit ear artery, neuropeptide Y (NPY, 0.3–100 nmol/l) had no direct vasoconstrictor action, but produced a concentration‐dependent and reversible enhancement of vasoconstrictor responses to both sympathetic nerve stimulation and exogenous noradrenaline. 2. In arteries in which the noradrenergic transmitter stores had been radiolabelled with [ 3 H]‐noradrenaline, 100 nmol/l NPY inhibited the stimulation‐induced (1 Hz for 30 s) release of radioactivity, but the lower concentrations tested (10 and 30 nmol/l) had no effect. NPY (10, 30 and 100 nmol/l) had no effect on the resting release of radioactivity. 3. Thus, NPY in low concentrations enhances vasoconstrictor responses in the rabbit ear artery by a postjunctional action; prejunctionally, NPY inhibits stimulation‐induced transmitter release when it is present in high concentrations.