Dantrolene (CAS No 7261-97-4) is a hydantoin derivative primarily used in the research category of muscle relaxants originating from its unique ability to interfere with excitation-contraction coupling in skeletal muscle Its mechanism of action involves blocking the ryanodine receptor (RyR1) calcium channels in the sarcoplasmic reticulum reducing calcium release and subsequent muscle contraction In vitro it exhibits activity in the nanomolar to low micromolar range Dantrolene is frequently applied in studies utilizing cell models to investigate calcium dynamics and neuroprotection as well as in animal studies exploring its potential in treating conditions such as malignant hyperthermia and muscular dystrophies It is also used in drug screening for therapeutic agents targeting calcium-related disorders Experimental concentrations typically depend on the specific research design