This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Mechanism of action of dantroline is ? 
Select and explain. 
A. Inhibits Ca++ secretion from sarcoplasm, B. Binds to ryanodine receptors to block release of Ca++, C. Inhibits GABA, D. Inhibits Gamma motor neuron
B: Binds to ryanodine receptors to block release of Ca++
Answer: B: Binds to ryanodine receptors to block release of Ca++ 
Explanation: Ans. is 'b' i.e., Binds to ryanodine receptors to block release of Ca++ o Dantrolone acts on Ryanodine receptors (RyR) Calcium channels in sarcoplasmic reticulum of skeletal muscles and prevents their depolarization triggered opening --> no release of intracellular Ca-+2 --> No excitation contraction coupling --> No contraction.