This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Pharmacology
Dantrolene sodium reduces skeletal muscle tone by: 
Select and explain. 
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
D: Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre
Answer: D: Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre 
Explanation: * 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.