Chwalisz K, Fahrenholz F, Hackenberg M, Garfield R, Elger W
Research Laboratories of Schering AG, Berlin, Germany.
Am J Obstet Gynecol. 1991 Dec;165(6 Pt 1):1760-70. doi: 10.1016/0002-9378(91)90030-u.
The progesterone antagonist onapristone was used in guinea pigs during late pregnancy (43 +/- 2 days after coitus) and before term (day 61 after coitus) to investigate the role of progesterone on uterine reactivity to exogenous oxytocin, concentration of oxytocin receptors, and gap junctions in the myometrium. Onapristone priming increased the ability of oxytocin to induce delivery during late pregnancy and before term by factors of greater than or equal to 30 and approximately 10, respectively. The intrauterine pressure recording on day 43 after coitus revealed phasic, laborlike contractions in response to oxytocin in onapristone-treated animals, in contrast to tonic reactions in controls. The increase in the oxytocin response in onapristone-treated animals was not associated with an increase in myometrial oxytocin receptor concentrations either during late pregnancy or before term. By contrast, treatment with onapristone significantly decreased the input resistance of myometrial cells in guinea pigs in late pregnancy (43 +/- 1 day after coitus) to the level of animals at term. This was associated with a marked increase in myometrial gap junctions stained with antibodies against connexin 43. These results indicate that progesterone may control myometrial reactivity to oxytocin in pregnant guinea pigs by effects on postreceptor events mainly by suppressing the gap junctions.
在豚鼠妊娠晚期（交配后43±2天）和足月前（交配后第61天）使用孕酮拮抗剂奥那司酮，以研究孕酮对子宫对外源性催产素的反应性、催产素受体浓度及子宫肌层缝隙连接的作用。奥那司酮预处理分别使妊娠晚期和足月前催产素诱导分娩的能力提高了大于或等于30倍和约10倍。交配后第43天的子宫内压力记录显示，与对照组的强直性反应相反，奥那司酮处理的动物对催产素产生了阶段性的、类似分娩的收缩。奥那司酮处理的动物对催产素反应的增加在妊娠晚期或足月前均与子宫肌层催产素受体浓度的增加无关。相比之下，奥那司酮处理显著降低了妊娠晚期（交配后43±1天）豚鼠子宫肌层细胞的输入电阻，使其降至足月动物的水平。这与用抗连接蛋白43抗体染色的子宫肌层缝隙连接显著增加有关。这些结果表明，孕酮可能主要通过抑制缝隙连接，对受体后事件产生影响，从而控制妊娠豚鼠子宫肌层对催产素的反应性。
