PORCINE MALIGNANT HYPERTHERMIA III: ADRENERGIC BLOCKADE

Abstract
The effects of the establishment of an adrenergic blockade on suxamethonium-induced porcine malignant hyperthermia (MH) were investigated in Pietrain pigs. Six animals were fed reserpine 10 mg daily for 7 days and then challenged with suxamethonium. Three survived but the remainder developed fatal MH. In a further study of 10 pigs, either phentolamine 40 (ig/kg/min or propranolol 50 ng/kg/min were administered for 30 min before suxamethonium stimulation and continued for the duration of the experiment. The five p-blocked pigs all became hyperthermic and died whereas the phentolamine-treated group survived. However, both a-adrenergic blockade and successful reserpinization failed to prevent the abnormal muscle response to the first dose of suxamethonium.