ATP-sensitive potassium channels influence how beta-2-adrenergic drugs relax uterine muscle in early but not late pregnancy in rats

On day 6 of pregnancy, β2-adrenergic receptor agonists induced myometrial relaxation that was inhibited by glibenclamide and enhanced by pinacidil.

• High expression levels of the K(ATP) channel sulphonylurea-binding regulatory subunit (SUR1) on day 6 are associated with the modulation of β2-AR agonist effects.
• No significant effects of glibenclamide or pinacidil were observed on day 22, suggesting decreased K(ATP) channel activity at this stage.
• The findings indicate that lower expression of K(ATP) channels towards the end of gestation may lead to increased excitability and contractility in the uterus.
• The combination of a β2-adrenergic agonist and a K(ATP) channel opener may not be therapeutically relevant for treating preterm delivery.

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