| Abstract: | The effects of the beta-sympathomimetic agent terbutalin (1-/3.5 dihydroxyphenyl/-allilaminoethane sulphonate) on maternal and foetal circulation were studied in 11 ewe at 110-130 days of pregnancy. None of them exhibited uterine contractions. Catheters were implanted in the carotid artery and jugular vein, together with four stainless steel electrodes on the limbs. Terbutalin was added intravenously in Ringer-lactate (5%) infusion (1 ml/min). The following maternal and foetal parameters were measured simultaneously: heart rate, central arterial pressure, blood glucose levels, ECG. Intravenous administration of 100 micrograms terbutalin resulted in a 19% increase of maternal and 10% enhancement of foetal heart rate. Maternal systolic blood pressure rose by 9%, whereas diastolic blood pressure fell by 7%. Maternal and foetal blood glucose levels was fairly constant during the entire experiment. In further six experiments terbutalin was administered into the foetal circulation (1 ml/3 min). The same effects on foetal heart rate and pulse pressure were observed as after injecting into the maternal circulation, however but the time necessary for the maximum action to develop was significantly shorter. |
