Gestational change of K⁺ channel opener effect is correlated with the expression of uterine K_ATP channel subunits

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• 作者：Kenjiro Sawada ; Ken-ichirou Morishige ; Kae Hashimoto ; Keiichi Tasaka ; Hirohisa Kurachi ; Yuji Murata and Yoshihisa Kurachi
• 刊名：European Journal of Obstetrics and Gynecology and Reproductive Biology
• 出版年：2005
• 期刊代码：92_03012115
• 类别：med
• 出版时间：2005
• 卷：122
• 期：1
• 页码：49-56
• 文件大小：244 K

摘要

Objective:

We analyzed the gestational changes of pharmacological activity and molecular levels of K_ATP channels in rat myometrium.

Study design:

Using rat myometrium, the effects of K⁺ channel openers (KCOs) were examined in an isometric tension study of oxytocin-induced contraction. We also examined the effects of KCOs on the intracellular Ca²⁺ levels of cultured myometrial cells. The expression of myometrial K_ATP channels was assessed by RT-PCR and Northern blot analysis.

Results:

The effect of KCOs were altered during pregnancy, with a significant increase of their potency at day 18 of pregnancy followed by a decline towards the non-pregnant level at the day of delivery. KCOs suppressed the Ca²⁺ influx across the cell membrane. The mRNAs encoding each component of myometrial K_ATP channels, Kir6.1 and SUR2B, exhibited gestational stage-dependent alterations similar to those of the effects of KCOs.

Conclusion:

These findings suggest that KCOs inhibit uterine myometrial contraction more effectively during pregnancy than in the non-pregnant state due to gestation-enhanced expression of K_ATP channels, implying that KCOs might be useful for preventing premature delivery.