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The role of neurally released NPY in neurogenic contractions of rat small mesenteric arteries
Author(s) -
Lamont Christine,
Wier W Gil
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a519-a
Subject(s) - neuropeptide y receptor , medicine , endocrinology , contraction (grammar) , phenylephrine , mesenteric arteries , chemistry , antagonist , norepinephrine , receptor antagonist , receptor , vasoconstriction , purinergic receptor , biology , neuropeptide , artery , dopamine , blood pressure
Perivascular sympathetic nerves of small arteries release norepinephrine (NE), ATP and Neuropeptide Y (NPY). NPY potentiates the effects of other neurotransmitters and is also a potent vasoconstrictor (> 100nM). Nevertheless, sympathetic neurogenic contractions of small arteries are abolished by combined blockade of purinergic and adrenergic receptors. Here, we sought to determine 1) if neurally released NPY contributes directly to contraction, and 2) how neurally released NPY might change Ca 2+ signaling. [NPY] of 0.15nM potentiates the contractions produced by KCl, phenylephrine (PE) and EFS. 10nM NPY produces a potentiation of 190.3 + 24.0 % (n=3) in the neurogenic contractions produced by 4Hz EFS, an effect which is antagonized by the Y1 receptor antagonist, BIBP 3226 (1 μM, Bachem). At higher frequencies of EFS (16Hz), BIBP 3226 reduced the size of the responses to 54 + 12 % (n=3) (suggesting an effect of neurally released NPY). Bath applied 10nM NPY alone produced no change in diameter, force, or cellular calcium levels (confocal, fluo‐4). NPY (10 nM) increases the frequency of Ca 2+ waves induced by 2 μM PE from 1.38±0.28 to 3.95±0.54 waves/cell/min (120 cells, 3 arteries, mean ± s.e.m.). We conclude that neurally released NPY potentiates neurogenic contraction of isolated rat mesenteric vessels via the Y1 receptor and that the mechanism involves increased frequency of contractile Ca 2+ waves. NIH RO1‐ HL073094