Abstract
1. An in vitro preparation of the rabbit knee joint, perfused with oxygenated Locke solution, was used to assess the nature of adrenoceptors within articular blood vessels. 2. Dose/response relationships were obtained to intra-arterial injection of alpha- and beta-adrenoceptor agonists. 3. Adrenaline and noradrenaline produced a similar pattern of increasing constriction of articular vessels with increasing dose of drug. 4. The alpha 1-agonist, phenylephrine, also produced dose-dependent constrictor responses, but the alpha 2-agonist; clonidine, had no effect. The alpha 2-agonist UK-14304 did, however, produce modest vasoconstriction which was not greatly altered by the alpha 1-blocker prazosin. The constrictor effect of noradrenaline was abolished by both the alpha 1,2-blocker phenoxybenzamine and by prazosin but not by the alpha 2-blocker rauwalscine. 5. The beta-adrenoceptor agonist, isoprenaline, had little effect at a dose of 10(-6) M or lower, but gave rise to a constrictor effect at higher concentrations. This response was blocked by phenoxybenzamine but not by the beta 1,2-blocker propranolol, suggesting that the constrictor effect was mediated via alpha-adrenoceptors. 6. The results suggest that alpha 1- and alpha 2-adrenoceptors are present within articular blood vessels, but that beta-receptors are absent. The effects of noradrenaline appear to be mediated principally via alpha 1-adrenoceptors.
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- COBBOLD A. F., LEWIS O. J. The action of adrenaline, noradrenaline and acetylcholine on blood flow through joints. J Physiol. 1956 Aug 28;133(2):472–474. doi: 10.1113/jphysiol.1956.sp005602. [DOI] [PMC free article] [PubMed] [Google Scholar]
- COBBOLD A. F., LEWIS O. J. The nervous control of joint blood vessels. J Physiol. 1956 Aug 28;133(2):467–471. doi: 10.1113/jphysiol.1956.sp005601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Knight A. D., Levick J. R. The influence of blood pressure on trans-synovial flow in the rabbit. J Physiol. 1984 Apr;349:27–42. doi: 10.1113/jphysiol.1984.sp015140. [DOI] [PMC free article] [PubMed] [Google Scholar]