Effects of XXXX on endothelin-induced constriction of myometrial arteries in normotensive pregnant @entity1 .

@entity1 @entity4768 @entity1468 @entity2232
The results of our previous studies suggested that @entity2232 ( @entity2232 ) might be contributory to the impaired uteroplacental blood flow seen in @entity1468 . The aim of this study was to investigate the in vitro influence of @entity4768 on @entity2232 -induced contraction of myometrial resistance arteries from pregnant @entity1 , as these vessels are partly responsible for the regulation of uteroplacental blood flow in @entity1468 . Small myometrial arteries were dissected from myometrium obtained from 20 normotensive term pregnant @entity1 undergoing elective cesarean section and mounted in a tissue chamber. Tension was recorded isometrically. When @entity2232 (10(-8) mol/L)-contracted vessels were exposed to increasing concentrations (10(-6), 10(-5), and 10(-4) mol/L) of @entity4768 , the myometrial arteries demonstrated essentially no relaxation. A significant mean relaxation of 31% was seen only with the highest @entity4768 concentration of 10(-3) mol/L. Pretreatment with @entity4768 attenuated @entity2232 -induced contraction by 26% at 3 x 10(-4) mol/L and by up to 80% at 10(-3) mol/L. Preincubation with lower concentrations of @entity4768 did not significantly reduce subsequent @entity2232 contraction. The present study has thus shown that @entity4768 at high concentrations counteracts @entity2232 -induced constriction of myometrial arteries in term pregnant @entity1 . Pretreatment with @entity4768 at high concentrations attenuates the @entity2232 contraction.
