OBJECTIVE: We analyzed the gestational changes of pharmacological activity and molecular levels of KATP 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 KATP 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 KATP 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 KATP channels, implying that KCOs might be useful for preventing premature delivery.
OBJECTIVE: We analyzed the gestational changes of pharmacological activity and molecular levels of KATP 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 KATP 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 KATP 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 KATP channels, implying that KCOs might be useful for preventing premature delivery.
Authors: Kevin Monaghan; Salah A Baker; Laura Dwyer; William C Hatton; Kyung Sik Park; Kenton M Sanders; Sang Don Koh Journal: J Physiol Date: 2011-01-10 Impact factor: 5.182
Authors: Chen Xu; Xingji You; Lu Gao; Lanmei Zhang; Rong Hu; Ning Hui; David M Olson; Xin Ni Journal: Reprod Biol Endocrinol Date: 2011-03-21 Impact factor: 5.211
Authors: Seung Hwa Hong; Kyu-Sang Kyeong; Chan Hyung Kim; Young Chul Kim; Woong Choi; Ra Young Yoo; Hun Sik Kim; Yeon Jin Park; Il Woon Ji; Eun-Hwan Jeong; Hak Soon Kim; Wen-Xie Xu; Sang Jin Lee Journal: J Vet Med Sci Date: 2016-04-18 Impact factor: 1.267