Morrison J J, Ashford M L, Khan R N, Smith S K
Department of Obstetrics and Gynaecology, University of Cambridge, Rosie Maternity Hospital, England.
Am J Obstet Gynecol. 1993 Nov;169(5):1277-85. doi: 10.1016/0002-9378(93)90294-s.
Our purpose was to investigate the effects and pharmacologic properties of potassium channel openers in isolated pregnant human myometrium.
Biopsy specimens of myometrium obtained from 67 women during pregnancy and labor were used for isometric recording under physiologic conditions.
Levcromakalim and pinacidil, two prototype potassium channel openers, are potent inhibitors of spontaneous and induced (0.5 nmol/L oxytocin and 10 mumol/L phenylephrine) contractions in isolated human pregnant myometrium, obtained before and after the onset of labor. The sulfonylurea glibenclamide is an apparent competitive antagonist of this inhibition. No antagonism was observed with the sulfonylurea tolbutamide. Both potassium channel openers significantly inhibited contractility evoked by low (10 and 20 mmol/L) but not high (40 and 80 mmol/L) concentrations of extracellular potassium chloride.
These findings suggest that the relaxant ability of levcromakalim and pinacidil in human pregnant myometrium is because of potassium channel activation. This introduces a potential new approach for tocolysis.
我们的目的是研究钾通道开放剂对离体妊娠人子宫肌层的作用及药理特性。
从67名孕妇分娩时获取的子宫肌层活检标本用于生理条件下的等长记录。
两种原型钾通道开放剂，即利克罗卡林和吡那地尔，是离体妊娠人子宫肌层自发性收缩和诱发性收缩（0.5 nmol/L缩宫素和10 μmol/L去氧肾上腺素）的强效抑制剂，这些子宫肌层标本取自分娩开始前后。磺脲类药物格列本脲是这种抑制作用的明显竞争性拮抗剂。未观察到磺脲类药物甲苯磺丁脲有拮抗作用。两种钾通道开放剂均显著抑制低浓度（10和20 mmol/L）而非高浓度（40和80 mmol/L）细胞外氯化钾诱发的收缩性。
这些发现表明，利克罗卡林和吡那地尔在人妊娠子宫肌层中的舒张能力是由于钾通道激活。这为安胎治疗引入了一种潜在的新方法。
