Postjunctional ?-adrenoceptors
- 1 May 1984
- journal article
- research article
- Published by Springer Nature in Naunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie
- Vol. 326 (1) , 1-6
- https://doi.org/10.1007/bf00518771
Abstract
The postsynaptic α-adrenoceptors in rat aorta and in pithed rat were investigated according to their sensitivity to nine α-adrenergic agonists and to the selective antagonists yohimbine (α2) and prazosin (α1) and the non-selective one, phentolamine. In addition, in radioligand binding studies, the affinity and selectivity of the drugs were determined on rat cerebral cortex using [3H] yohimbine and [3H] prazosin. On rat aorta, prazosin is 1,000 times more potent than yohimbine against each α-adrenoceptor agonist, whether α1- or α2-selective. Rat aorta probably contains only α1-adrenoceptors. Pressor effects in pithed rats are mediated by post-junctional α1- and α2-adrenoceptors. The dose-response curve for α-methylnorepinephrine in the presence of prazosin, using Hofstee's plots, revealed α1- and α2-adrenoceptors, respective proportions being 80.5 and 19.5%Keywords
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