Chaud M A, Franchi A M, Beron de Astrada M, Gimeno M F
Centro de Estudios Farmacológicos y Botánicos, Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina.
Prostaglandins Leukot Essent Fatty Acids. 1997 Sep;57(3):323-9. doi: 10.1016/s0952-3278(97)90551-2.
Uterine contractions elicited by oxytocin (OT), possibly linked with uterus prostaglandin (PG) release, are involved in the final pathway of labor. It is known that nitric oxide (NO) may contribute to the maintenance of uterine contractile quiescence during gestation. Therefore in this study the effect of the inhibition of NO synthase (NOS), with N-monomethyl L-arginine (L-NMMA), on the ability of OT to stimulate uterine contractions and PG synthesis was investigated in isolated rat uterus at days 13 and 21 of pregnancy. L-NMMA did not modify the frequency and the force of contractions elicited by OT at day 13. On day 21 the frequency of contractions evoked by OT were better sustained in the presence of L-NMMA. PGs were not affected by OT on day 13. OT stimulated PGF2alpha on day 21 when NOS had been inhibited with L-NMMA, but not in the absence of L-NMMA. NOS activity was stimulated by OT at day 21 of gestation. In summary these findings indicate that near term NO can regulate OT PGF2alpha induced contractions and PG synthesis in isolated pregnant rat uterus.
催产素（OT）引发的子宫收缩可能与子宫前列腺素（PG）释放有关，参与分娩的最终过程。已知一氧化氮（NO）可能有助于维持妊娠期子宫收缩的静息状态。因此，在本研究中，在妊娠第13天和第21天的离体大鼠子宫中，研究了用N-单甲基-L-精氨酸（L-NMMA）抑制一氧化氮合酶（NOS）对OT刺激子宫收缩和PG合成能力的影响。L-NMMA在第13天未改变OT引发的收缩频率和力量。在第21天，在L-NMMA存在的情况下，OT诱发的收缩频率得到更好的维持。PG在第13天不受OT影响。在第21天，当用L-NMMA抑制NOS时，OT刺激了PGF2α的产生，但在没有L-NMMA的情况下则没有。在妊娠第21天，OT刺激了NOS活性。总之，这些发现表明，在妊娠晚期，NO可以调节OT诱导的PGF2α收缩和离体妊娠大鼠子宫中的PG合成。
