Which channel is defective in "Malignant Hyperpyrexia"?

Malignant hypehermia:Inheritance is autosomal dominanceThe defect is located on the long arm of chromosome 19 involving the Ryanodine receptor of the skeletal muscle sarcoplasmic reticulumThis is associated with L-type calcium channelsThere will be a rapid increase in intracellular calcium level in response to halothane and other inhalational anaesthetics or to succinylcholineFeatures are:Elevated temperature,increased muscle metabolism, muscle rigidity, rhabdomyolysis, acidosis and cardiovascular instability develop within minutesThis rare condition is often fatal (ref: Harrison's 17/e p118, 18/e p144)