The action of angiotensin II on the baroreflex response of the conscious ewe and the conscious fetus.

摘要: 1. In conscious non-pregnant and pregnant ewes in chronic fetal lamb preparations, the beat by relationship between pulse interval systolic pressure was studied during acute elevations arterial induced phenylephrine. Baroreflex sensitivity, which defined as slope of pressure-pulse when phenylephrine used to raise pressure, abolished atropine increased propranolol. sensitivity less foetal lambs compared with ewes. 2. These findings suggest that vagus nerve is responsible for reflex bradycardia occurs foetus ewe increased. 3. both adult sheep, actue hypertension due I.V. injection angiotensin II not associated a consistent progressive bradycardia, such seen caused Angiotensin has no direct chronotropic effect on heart rate either or fetus. 4. No linear sheep were treated Therefore lack cardiac slowing pressor doses concomitant activation sympathoadrenal system. 5. It concluded reduces increase vagal tone response rises pressure.