An examination of the postjunctional α-adrenoceptor subtypes for (−)-noradrenaline in several isolated blood vessels from the rabbit

Daly, C.J. , McGrath, J.C. and Wilson, V.G. (1988) An examination of the postjunctional α-adrenoceptor subtypes for (−)-noradrenaline in several isolated blood vessels from the rabbit. British Journal of Pharmacology, 95(2), pp. 473-484. (doi: 10.1111/j.1476-5381.1988.tb11668.x)

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Abstract

1: Postjunctional α-adrenoceptors in several isolated blood vessels from the rabbit have been characterized on the basis of the relative potency of the agonists noradrenaline (NA, non-selective), phenylephrine (α1-selective) and UK-14304 (α2-selective), and the potency of antagonists rauwolscine (α2-selective) and corynanthine (α1-selective) against contractions elicited by NA. In addition, the potency of prazosin against NA was also assessed in the venous preparations.<p></p> 2: The thoracic aorta, ear artery and left renal vein appear to possess α1-adrenoceptors since the agonist potency order was NA > phenylephrine > UK-14304, while corynanthine was 3–10 fold more potent than rauwolscine.<p></p> 3: The ear vein appears to possess α2-adrenoceptors. The rank order of agonist potency was UK-14304 > NA > phenylephrine and all three agonists elicited responses of similar magnitude. Furthermore, rauwolscine was 30 fold more potent than corynanthine while prazosin failed to produce a concentration-dependent inhibition.<p></p> 4: The saphenous vein and the plantaris vein appear to possess a mixture of both subtypes since the rank order of agonist potency was UK-14304 > NA ≫ phenylephrine, while responses elicited by UK-14304 were smaller than those to the other agonists. However, although rauwolscine was 20 to 100 fold more potent than corynanthine in both preparations, suggestive of predominantly α2-adrenoceptors, prazosin was either potent (saphenous vein) or relatively inactive (plantaris vein).<p></p> 5: The characteristics of postjunctional α1- and α2-adrenoceptors on isolated blood vessels from the rabbit are discussed in relation to the value of both the agonists, particularly NA, and the antagonists used in this study.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McGrath, Professor John and Daly, Dr Craig
Authors: Daly, C.J., McGrath, J.C., and Wilson, V.G.
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:British Journal of Pharmacology
Publisher:John Wiley & Sons, Inc.
ISSN:0007-1188
ISSN (Online):1476-5381

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