Influence of terbutaline on ovine uterine response to prostaglandin E2 challenge

OBJECTIVE: Our purpose was to test the effects of terbutaline on uterine electric and contractile responses to prostaglandin E 2 . STUDY DESIGN: In five late-gestation ewes, prostaglandin E 2 (22.9 ± 2.3 μg/min for 3 minutes) was given twice at 30-minute intervals during control. Terbutaline sulfate (2 μg/min) was then infused for 30 minutes. Prostaglandin E 2 challenge was repeated 10 minutes after the onset of terbutaline infusion and thereafter at 30-minute intervals. Two-way analysis of variance for repeated measures revealed a significant main effect for time ( p ≤ 0.0001) and between time and response ( p ≤ 0.05). RESULTS: Both electric ( p ≤ 0.0001) and intrauterine pressure ( p ≤ 0.0001) responses were suppressed during terbutaline. The influence on intrauterine pressure persisted 10 minutes after terbutaline ( p ≤ 0.01) while the electric response was not different from control. CONCLUSIONS: Terbutaline initially diminishes both uterine contractile and electric activity, but electric recovery precedes contractile recovery.