el Alj A, Bonoris E, Cynober E, Germain G
Maternité Baudelocque, INSERM U166, Paris, France.
Eur J Pharmacol. 1990 Sep 21;186(2-3):231-8. doi: 10.1016/0014-2999(90)90438-c.
The contractile response of longitudinal and circular strips of rat myometrium to oxytocin (OT), [Arg8]vasotocin (AVT) and [Arg8]vasopressin (AVP) was examined in vitro in late pregnancy (controls at day 20, day 21, day 22) and 24 h after treatment with the antiprogestin, RU 486 (or mifepristone, given on day 20 or day 21 of gestation). In controls, the maximal effect (Emax) of OT in longitudinal strips increased with gestation, but there was no change in OT sensitivity in either myometrial layer. The pA2 values for the OT/AVP V1 antagonist, d(CH2)5[Tyr(Me)2]OVT, against OT, AVT and AVP on longitudinal strips and against AVT and AVP on circular strips were not different. However, the antagonist did not inhibit the effect of OT in circular strips, indicating that the receptor activated by OT is different from that in longitudinal strips. RU 486 treatment did not modify the characteristics of responses to AVT and AVP. RU 486 improved the response to OT in circular strips from rats treated at day 20, however the sensitivity to OT in longitudinal strips was decreased compared to that in the controls.
在妊娠晚期（对照组为第20天、第21天、第22天）以及用抗孕激素RU 486（或米非司酮，在妊娠第20天或第21天给予）处理24小时后，在体外检测大鼠子宫肌层纵行条和环形条对催产素（OT）、[精氨酸8]加压素（AVT）和[精氨酸8]血管升压素（AVP）的收缩反应。在对照组中，纵行条中OT的最大效应（Emax）随妊娠进展而增加，但子宫肌层两层中OT的敏感性均无变化。OT/AVP V1拮抗剂d(CH2)5[Tyr(Me)2]OVT对纵行条上的OT、AVT和AVP以及环形条上的AVT和AVP的pA2值无差异。然而，该拮抗剂不抑制环形条中OT的作用，表明OT激活的受体与纵行条中的不同。RU 486处理未改变对AVT和AVP的反应特征。RU 486改善了第20天处理的大鼠环形条对OT的反应，然而与对照组相比，纵行条对OT的敏感性降低。
