Referenced in: none

Automatically associated channels: Kir6.1

Title: Gestational change of K+ channel opener effect is correlated with the expression of uterine KATP channel subunits.

Authors: Kenjiro Sawada, Ken-ichirou Morishige, Kae Hashimoto, Keiichi Tasaka, Hirohisa Kurachi, Yuji Murata, Yoshihisa Kurachi

Journal, date & volume: Eur. J. Obstet. Gynecol. Reprod. Biol., 2005 Sep 1 , 122, 49-56

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16154039

Abstract
We analyzed the gestational changes of pharmacological activity and molecular levels of KATP channels in rat myometrium.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 KATP channels was assessed by RT-PCR and Northern blot analysis.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 KATP channels, Kir6.1 and SUR2B, exhibited gestational stage-dependent alterations similar to those of the effects of KCOs.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 KATP channels, implying that KCOs might be useful for preventing premature delivery.