Effects of catecholamines on pregnant rat uterus.
1 The effects of noradrenaline (NA), adrenaline (Adr) and isoprenaline (Iso) have been studied on pregnant rat uterus, at various stages of gestation--on the 10th and 20th days of pregnancy and on the first day post-partum. 2 The three catecholamines were inhibitory in all stages of gestation, with the same order of potency as observed in non-pregnant uteri (ie Iso greater than Adr greater than NA). However, mean pD2 values for the catecholamines tended to decrease as gestation progressed. 3 In 20 day pregnant and 1 day post-partum uteri, in the presence of propranolol, NA and Adr produced consistent alpha-adrenoreceptor mediated motor responses. 4 It is concluded that in the rat uterus, a form of pregnancy reversal occurs, in that there is a decrease in beta-adrenoreceptor responsiveness, and an increase in alpha-adrenoreceptor responsiveness towards the end of gestation, and immediately post-partum.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000187:drug effects; D014590:Uterine Contraction / Q000187:drug effects; D014599:Uterus / Q000187:drug effects*
D002395:Catecholamines; D011941:Receptors, Adrenergic; D007545:Isoproterenol; D000109:Acetylcholine; D009638:Norepinephrine; D004837:Epinephrine