NCIt definition : The sodium salt form of dantrolene, a hydantoin derivative and direct-acting skeletal
muscle relaxant. Dantrolene depresses excitation-contraction coupling in skeletal
muscle by binding to the ryanodine receptor 1, and decreasing intracellular calcium
concentration. Ryanodine receptors mediate the release of calcium from the sarcoplasmic
reticulum, an essential step in muscle contraction.;