Pattern of summation with fatigue and inhibition of calcium release in rat muscle.

Introduction: Fatigue disrupts muscle force summation and is associated with a decrease in cytoplasmic Ca(2+) concentration. The purpose of this study was to compare summation during fatigue and recovery with summation during dantrolene-induced inhibition of Ca(2+) release.

Methods: Rat medial gastrocnemius muscles were evaluated before and after fatigue, or during exposure to dantrolene.