Effect of ryanodine in dog mesenteric artery: Interference with potassium and adrenergic stimulation

Ryanodine, a selective pharmacological tool affecting sarcoplasmic reticulum Ca²⁺-release channels in skeletal and cardiac muscles, was tested on contractions induced in the dog mesenteric artery by high-KCl depolarization and α-adrenergic stimulation. Ryanodine significantly potentiated tonic contractions induced by low-KCl (25-45 mM) and norepinephrine (30 nM-3 μM) stimulations. KCl potentiation was only partly sensitive to nifedipine and …