RYR1 and Malignant hyperthermia: Dantrolene, an antagonist of the ryanodine receptor (RYR) calcium (Ca2+) channel, which is located in the membrane of the sarcoplasmic reticulum (SR) in muscle cells and the endoplasmic (ER) reticulum in neurons, is clinically used to treat muscle spasticity and malignant hyperthermia (MH) in patients, reducing MH mortality from 64% to 1.4% [1, 2].