Open AccessEffects of Terbutaline on Human Uterine Motility at Term
Author(s) -
Andersson K.E.,
Ingemarsson I.,
Persson C. G. A.
Publication year - 1975
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016347509156750
Subject(s) - terbutaline , practolol , myometrium , propranolol , medicine , uterine contraction , endocrinology , motility , tocolytic , heart rate , in vivo , oxytocin , receptor , uterus , fetus , blood pressure , preterm labor , pregnancy , biology , microbiology and biotechnology , asthma , genetics
. The effects of the selective β 2 ‐receptor stimulator terbutaline on the activity of gravid, human myometrium were investigated in vitro and in vivo, before and after administration of different β‐receptor blockers. Terbutaline, 0.2‐1.0 μg/ml, inhibited the spontaneous contractile activity of isolated strips of myometrium. This effect was unaffected by the selective β 1 ‐receptor blockers practolol, 1 μg/ml, and H 93/26, 1 μg/ml. However, the non‐selective blocker propranolol, 0.1 μg/ml, completely inhibited the terbutaline effects. The in vitro effects of terbutaline could be correlated with findings in vivo. Intra‐uterine pressure was recorded in 4 pregnant women at term. Infusion of terbutaline, 10‐15 μg/min, for 20‐40 min, effectively inhibited both spontaneous and oxytocin‐stimulated uterine activity. There was a moderate increase in maternal heart rate, but no consistent effect on maternal blood pressure. Fetal heart rate was little affected. The uterine effects of terbutaline were not influenced by practolol, 5‐20 mg i.v., but completely inhibited by propranolol, 1‐2 mg i.v. The results suggest that terbutaline inhibits uterine motility by effects on uterine β 2 ‐receptors and that it can be given in clinically effective doses without adverse circulatory effects on mother or fetus.