QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: jpet.103.056184v1 308/1/350    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pérez-Rivera, A. A. Articles by Galligan, J. J. Search for Related Content PubMed PubMed Citation Articles by Pérez-Rivera, A. A. Articles by Galligan, J. J. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB PHENOXYBENZAMINE

CARDIOVASCULAR

Increased Reactivity of Murine Mesenteric Veins to Adrenergic Agonists: Functional Evidence Supporting Increased ₁-Adrenoceptor Reserve in Veins Compared with Arteries

Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan

These studies examined adrenergic reactivity of mesenteric arteries and veins from deoxycorticosterone acetate-salt (DOCA-salt) hypertensive and sham control mice. We measured constrictions in unpressurized arteries and veins by monitoring vessel diameter using computer-assisted video micros-copy in vitro. Veins were more sensitive than arteries to the constricting effects of norepinephrine (NE) and phenylephrine (PE), but the ₂-agonists clonidine and UK 14,304 [5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline] did not constrict arteries or veins. Reactivity was not altered in arteries or veins from DOCA-salt mice. We next investigated the mechanism of increased venous reactivity to NE and PE by studying desensitization to maximum concentrations of NE and PE. Sham arteries desensitized to NE and PE more than DOCA-salt arteries, whereas DOCA-salt and sham veins maintained 80% of the initial NE and PE constriction. To determine whether the increased reactivity and resistance to desensitization in veins was due to a greater -adrenoceptor reserve, vessels were incubated with the alkylating agent phenoxybenzamine (PBZ; 0.3, 3, 10, and 30 nM). The NE-elicited initial constriction was reduced by PBZ (3, 10, and 30 nM) in sham but only by PBZ (30 nM) in DOCA-salt veins. All doses of PBZ blocked NE responses in sham and DOCA-salt arteries. These data suggest that mesenteric veins express more ₁-adrenoceptors than arteries, accounting for greater reactivity and resistance to desensitization compared with arteries.

Address correspondence to: Alex A. Pérez-Rivera, Michigan State University, Department of Pharmacology and Toxicology, B 440 Life Sciences, East Lansing, MI 48824. E-mail: perezriv{at}msu.edu

This article has been cited by other articles:

				H. Xu, G. D. Fink, and J. J. Galligan Increased sympathetic venoconstriction and reactivity to norepinephrine in mesenteric veins in anesthetized DOCA-salt hypertensive rats Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H160 - H168. [Abstract] [Full Text] [PDF]