[Decrease of the contraction force of skeletal muscle in mammals by the potassium channel activator, SR 44866].

The ATP-sensitive K channel opener, SR 44866, was applied to intact extensor digitorum muscle of the mouse. Electrically stimulated maximal twitch contractions of the muscle were decreased by SR 44866 with a KD of 7.4 microM and a Hill coefficient of 1.2 at 34 degrees C. The effect of SR 44866 was antagonized by glibenclamide and reduced at 24 degrees C. We suggest that these results represent the consequence of activation of ATP-sensitive K channels in mammalian skeletal muscle.