Activation of K+ channels by ritodrine hydrochloride in uterine smooth muscle cells from pregnant women.

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Hamada Y, Nakaya Y, Hamada S, Kamada M, Aono T

Activation of K+ channels by ritodrine hydrochloride in uterine smooth muscle cells from pregnant women.

Eur J Pharmacol. 1994 Dec 15;288(1):45-51. doi: 10.1016/0922-4106(94)90008-6.

PubMed ID

7705467 [ View in PubMed

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Abstract

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 Ca(2+)-activated K+ (KCa) channel and the ATP-sensitive K+ (KATP) channel. Forskolin (10(-4) M), an activator of adenylate cyclase, and protein kinase A activated the KCa channel. In addition, 10(-4) M GTP activated the KCa channel in inside-out patches using a pipette containing 10(-5) M ritodrine. The KATP 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 KCa channel via direct gating by GTP-binding proteins and possibly via cAMP-dependent phosphorylation, and the KATP channel possibly via cAMP-dependent phosphorylation. These mechanisms partially explain the relaxing effect of ritodrine hydrochloride.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Colforsin	Calcium-activated potassium channel (Protein Group)	Protein group	Humans	Unknown	Activator	Details
Ritodrine	ATP-sensitive potassium channel (Protein Group)	Protein group	Humans	Yes	Activator	Details
Ritodrine	Beta adrenergic receptor (Protein Group)	Protein group	Humans	Yes	Agonist Downregulator	Details
Ritodrine	Calcium-activated potassium channel (Protein Group)	Protein group	Humans	Yes	Activator	Details