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Postjunctional Alpha 2-adrenoceptors Mediate Vasoconstriction in Human Subcutaneous Resistance Vessels

Overview
Journal Br J Pharmacol
Publisher Wiley
Specialty Pharmacology
Date 1989 Jul 1
PMID 2547487
Citations 11
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Abstract

1. In vitro studies have been performed on human medium-sized muscular arteries (internal diameter 1-4 mm) in a classical organ bath and with human subcutaneous resistance arteries (internal diameter 103-626 microns) in a microvascular myograph. 2. Although the medium-sized muscular arteries showed no response to either of the alpha 2-agonists B-HT 933 or UK 14304 in concentrations up to 10 microM, the subcutaneous resistance arteries from all regions examined showed well-pronounced and concentration-dependent responses to B-HT 933, the pD2 (-log EC50) being 5.11 +/- 0.09. 3. In the resistance arteries the alpha 2-antagonist yohimbine caused a parallel shift to the right of the B-HT 933 concentration-response curve; the yohimbine pA2 for the B-HT 933 receptor was 7.86 +/- 0.12. 4. There was an inverse relationship between the maximum response to B-HT 933 and the calibre of the resistance vessels. 5. These results indicate the presence of a postjunctional alpha 2-adrenoceptor in human subcutaneous resistance arteries and not in medium sized muscular arteries.

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References
1.
Mulvany M, Halpern W . Contractile properties of small arterial resistance vessels in spontaneously hypertensive and normotensive rats. Circ Res. 1977; 41(1):19-26. DOI: 10.1161/01.res.41.1.19. View

2.
Moulds R, Jauernig R . Mechanism of prazosin collapse. Lancet. 1977; 1(8004):200-1. DOI: 10.1016/s0140-6736(77)91808-6. View

3.
Timmermans P, van Zwieten P . Postsynaptic alpha 1- and alpha 2-adrenoceptors in the circulatory system of the pithed rat: selective stimulation of the alpha 2-type by B-HT 933. Eur J Pharmacol. 1980; 63(2-3):199-202. DOI: 10.1016/0014-2999(80)90446-x. View

4.
McGrath J . Evidence for more than one type of post-junctional alpha-adrenoceptor. Biochem Pharmacol. 1982; 31(4):467-84. DOI: 10.1016/0006-2952(82)90147-2. View

5.
Elliott H, Reid J . Evidence for postjunctional vascular alpha 2-adrenoceptors in peripheral vascular regulation in man. Clin Sci (Lond). 1983; 65(3):237-41. DOI: 10.1042/cs0650237. View