ACTIVATION OF K+ CHANNELS BY RITODRINE HYDROCHLORIDE IN UTERINE SMOOTH-MUSCLE CELLS FROM PREGNANT-WOMEN
ACTIVATION OF K+ CHANNELS BY RITODRINE HYDROCHLORIDE IN UTERINE SMOOTH-MUSCLE CELLS FROM PREGNANT-WOMEN
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DOI：
10.1016/0922-4106(94)90008-6
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发表时间：
1994-12-15
期刊：
影响因子：
--
通讯作者：
AONO, T
中科院分区：
文献类型：
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作者：
HAMADA, Y;NAKAYA, Y;AONO, T
本研究探讨了盐酸利托君激活人子宫平滑肌细胞中 K+ 通道的机制。膜片钳技术用于记录单通道电流。 Ritodrine (10(-5) M) 在培养的孕妇子宫平滑肌细胞中激活两种类型的 K+ 通道：Ca2+ 激活的 K+ (K-Ca) 通道和 ATP 敏感的 K+ (K-ATP) 通道。 Forskolin (10(-4) M) 是腺苷酸环化酶的激活剂，蛋白激酶 A 激活 K-Ca 通道。此外，使用含有10(-5) M利托君的移液器，10(-4) M GTP激活由内而外贴片中的K-Ca通道。 K-ATP 通道被蛋白激酶 A 激活，但不被 10(-4) M GTP 激活。 β-肾上腺素受体激动剂利托君可激活两种类型的 K+ 通道：通过 GTP 结合蛋白直接门控并可能通过 cAMP 依赖性磷酸化的 K-Ca 通道，以及可能通过 cAMP 依赖性磷酸化的 K-ATP 通道。这些机制部分解释了盐酸利托君的放松作用。
This study investigated the mechanism of activation of K+ channels by ritodrine hydrochloride in human myometrial smooth muscle cells. The patch-clamp technique was used for recording single channel currents. Ritodrine (10(-5) M) activated two types of K+ channels in cultured uterine smooth muscle cells from pregnant women: the Ca2+-activated K+ (K-Ca) channel and the ATP-sensitive K+ (K-ATP) channel. Forskolin (10(-4) M), an activates of adenylate cyclase, and protein kinase A activated the K-Ca channel. In addition, 10(-4) M GTP activated the K-Ca channel in inside-out patches using a pipette containing 10(-5) M ritodrine. The K-ATP channel was activated by protein kinase A, but not by 10(-4) M GTP. The beta-adrenoceptor agonist ritodrine activates two types of K+ channels: the K-Ca channel via direct gating by GTP-binding proteins and possibly via cAMP-dependent phosphorylation, and the K-ATP channel possibly via cAMP-dependent phosphorylation. These mechanisms partially explain the relaxing effect of ritodrine hydrochloride.