REDUCTION OF HEART LESIONS AFTER EXPERIMENTAL RESTRAINT STRESS - A STUDY IN STRESS-SUSCEPTIBLE PIGS

Pigs, crossbreeds of Swedish Landrace and Yorkshire, about 6 months ol d and susceptible to develop malignant hyperthermia when exposed to ha lothane, were subjected to a 12-min experimental stress provoked by th e myorelaxant succinylcholine. The experimental pigs were pre-treated before the stress: five were given propranolol for one week, six were given alpha-tocopherol (vitamin E) combined with selenium for 11 days, and five pigs were pre-created with zinc (ZnSO4) for 1 month. A total of 12 untreated, stress-susceptible pigs served as controls. The bloo d levels of noradrenaline and adrenaline recorded during the stress we re significantly reduced in the groups pre-treated with propranolol or cu-tocopherol combined with selenium. The results show significant re duction of myocardial necrosis by P-adrenoceptor-blocking agents and f ree-radical scavengers during stress-induced increased sympathetic act ivity.