Dantrolene sodium reduces skeletal muscle tone by:: (A) Reducing acetylcholine release from motor nerve endings, (B) Suppressing spinal polysynaptic reflexes, (C) Inhibiting the generation of muscle action potential, (D) Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre
Answer is D. * Dantrolene is the drug of choice for the treatment of malignant hypehermia and neuroleptic malignant syndrome. * It acts as an antagonist of Ryanodine receptors (present on smooth endoplasmic reticulum). It inhibits the release of Ca2+ from sarcoplasmic reticulum in the muscle fibre.