The nature of the adrenoceptors in the post‐partum rat uterus

Abstract

1 Uteri were removed from rats 0·5 h to 8 days after parturition and were suspended in Locke solution at 37° C. 2 The agonists isoprenaline, adrenaline, noradrenaline and phenylephrine produced an inhibition of the post-partum rat uterus. 3 In the presence of propranolol, the agonists noradrenaline, adrenaline, and phenylephrine had an excitatory effect on the post-partum rat uterus. This excitatory effect was blocked by phenoxybenzamine indicating that it is mediated through α-adrenoceptors. 4 These excitatory α-adrenoceptors could be demonstrated for 5–6 days after parturition. By the 7th-8th days their existence was no longer apparent. 5 Excitatory α-adrenoceptors were also demonstrated in the late pregnant rat uterus.