DECREASED PHOSPHOLIPID POLYUNSATURATED FATTY-ACID CONTENT AND SUPEROXIDE-DISMUTASE ACTIVITY IN CARDIAC-MUSCLE OF MALIGNANT HYPERTHERMIA-SUSCEPTIBLE SWINE

Homogenates of cardiac left ventricle from malignant hyperthermia-susc eptible (MHS) pigs produced a circa 72% more pentane than those from m alignant hyperthermia-resistant (MHR) animals, indicating enhanced per oxidation of n-6 fatty acids. This is consistent with the observed cir ca 70% decrease in total phospholipid polyunsaturated fatty acids (PUF A) in MHS compared with MHR tissue, a decrease mainly due to the quant itatively greater loss of n-6 PUFA. Although the percentage loss of n- 3 PUFA was greater than that of n-6 PUFA (90% vs 60%), absolute amount s were insufficient to register as ethane production. Three-fold great er phospholipid content of MHS compared with MHR ventricles indicates reduced neutral lipid content probably due to increased catecholamine stimulation. These findings were associated with a small but significa nt decrease in superoxide dismutase activity in MHS tissues.