Endothelin type A receptor antagonist attenuates placental ischemia–induced hypertension and uterine vascular resistance

Objective We sought to determine the effect of an endothelin type A receptor antagonist (ETA) on uterine artery resistive index (UARI) and mean arterial pressure (MAP) in a placental ischemia rat model of preeclampsia produced by reduction in uterine perfusion pressure (RUPP). Study Design UARI was assessed by Doppler velocimetry in RUPP and normal pregnant controls (NP) on gestational days (GD) 12, 15, and 18. UARI was also determined on GD 18 in NP and RUPP pregnant dams after pretreatment with ETA. MAP was recorded on GD 19. Results The RUPP group had a higher MAP and UARI on GD 15 and 18 than the NP group. Pretreatment with ETA attenuated both the MAP and GD-18 UARI in the RUPP group without affecting these parameters in the NP group. Conclusion The improvement in UARI could be one potential mechanism for the reduction in MAP in response to ETA in pregnant dams with ischemic placentas.