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Independence of Connexin Expression and Vasomotor Conduction from Sympathetic Innervation in Hamster Feed Arteries
Author(s) -
LOOFTWILSON ROBIN C.,
HAUG SARA J.,
NEUFER P. DARRELL,
SEGAL STEVEN S.
Publication year - 2004
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1080/10739680490457782
Subject(s) - vasomotor , denervation , medicine , anatomy , connexin , vasoconstriction , endocrinology , gap junction , vasodilation , biology , microbiology and biotechnology , intracellular
Objective: Vasomotor responses can travel along the wall of resistance microvessels by two distinct mechanisms: cell‐to‐cell conduction through gap junctions or the release of neurotransmitter along perivascular nerves. It is unknown whether vascular innervation influences the expression of connexin molecules which comprise gap junctions, or the conduction of vasomotor responses. In feed arteries of the hamster retractor muscle (RFA), the authors tested whether sympathetic denervation would alter the expression of connexin isoforms and the conduction of vasomotor responses. Methods: Using intact vessels with sympathetic innervation and those 7–8 days following denervation surgery, mRNA expression was quantified using real‐time PCR, cellular localization of Cx protein was characterized using immunohistochemistry, and vasomotor responses to dilator and constrictor stimuli were evaluated in isolated pressurized RFA. Results: Connexin protein localization and mRNA expression were similar between innervated and denervated vessels. mRNA levels were Cx43 = Cx37 > Cx45 ≫ Cx40. Vasodilation to acetylcholine conducted ≥2000 μ m along innervated and denervated vessels, as did the biphasic conduction of vasoconstriction and vasodilation in response to KCl. Vasoconstriction to phenylephrine conducted < 500 μ m and was attenuated ( p < .05) in denervated vessels. Conclusions: The profile of connexin expression and the conduction of vasomotor responses are largely independent of sympathetic innervation in feed arteries of the hamster retractor muscle (RFA).