Pharmacological characterization of the postsynaptic α-adrenoceptors in human uterine artery

Publisher Website
Google Scholar
Abstract
Prazosin and yohimbine were used to differentiate postjunctional α-adrenoceptors in the human uterine artery in-vitro. Two postjunctional α-adrenoceptor subtypes were distinguished by the affinities of the receptor for yohimbine and prazosin. The pA2 for prazosin was 8.91 against phenylephrine with a slope not significantly different from unity (0.91), and the pA2 for yohimbine was 7.25 against naphazoline and 8.70 against clonidine, with slopes not significantly different from unity (1.11 and 1.18, respectively). Yohimbine was not very active against phenylephrine, while prazosin was very active against the mixed and selective α2-adrenoceptor agonist noradrenaline and clonidine; the intercepts of the Schild plot were 8.80 and 8.82 but with slopes significantly less than unity (0.77 and 0.67, respectively). Prazosin competitively antagonized phenylephrine at the α1-adrenoceptor, whereas yohimbine competitively antagonized naphazoline and clonidine at the α2-adrenoceptor. It is concluded that both α1- and α2-adrenoceptors are present in the human uterine artery.

This publication has 0 references indexed in Scilit: