Intravenous injections of superoxide dismutase into rats with amygdaline kindling mitigated spontaneous and electrostimulation-induced epileptic seizures and raised the thresholds of electric current for their elicitation; these seizures of reduced intensity were observed during 3 days following chronic (for 6 days) treatment with this enzyme. In contrast, superoxide dismutase injections had no effect on the convulsions induced by electric shock or corazole.Key Words: epileptic activity; amygdaline kindling; superoxide dismutase A number of pathological conditions including, among others, arterial hypertension, brain injuries, and tissue ischemia after heavy blood loss, involve functional and biochemical changes that lead to the formation of free radicals [3,7]. These radicals can probably be generated in the course of arachidonic acid metabolism [10,15], which is enhanced during convulsions [4]. It has also been shown that the intensified synthesis of cyclooxygenase products in the brain of animals with experimentally induced convulsive seizures may be accompanied by the production of free oxygen radicals [1,7].Superoxide dismutase (SOD; EC 1.15.1.1) is an enzyme catalyzing the reaction of superoxide radical disproportionation and thereby reducing concentrations of this radical in tissues. Exogenous SOD injected into the amygdala has been shown capable of reducing the brain's convulsive activity resulting from kindling [9,11], but the impact of SOD on physiological parameters following its en- try into the circulation has not been addressed. To gain better insight into the mechanism by which SOD exerts an anticonvulsive effect, it is important to establish whether SOD is able to act within the vascular bed, for, being a high molecular protein, this enzyme is likely to cross the blood-brain barrier only in minute quantities if at all.In this work we examined the effects from intravenous SOD injections on convulsive and electroencephalographic manifestations of epilepsy in rats with amygdaline kindling and in those with generalized convulsive seizures induced by the drug corazole or by electric shock.
MATERIALS AND METHODSThe effect of SOD on amygdaline kindling was evaluated in 25 sexually mature male Wistar rats weighing 250-300 g. Intracerebral electrodes were implanted under Nembutal anesthesia (40 mg/kg intmperitoneally) by stereotaxic technique (the coordinates were determined using a stereotaxic atlas of the rat brain [12]). During the implantation operation, bundles each consisting of three nichro-
We determined the effect of the antioxidants superoxide dismutase, desferrioxamine and allopurinol on the survival of male CBA mice infected intranasally with 2-5 LD 50 lung influenza virus A/Aichi/2/68. Survival for at least 20 days was observed for 45% of the mice that received 1000 U/day superoxide dismutase prepared from red blood cells on days 5, 6, 7 and 8 after infection, and 75% survival was observed for mice that received the same dose on days 4, 5, 6, 7 and 8. Desferrioxamine, 25 mg/kg per day and 100 mg/kg per day injected subcutaneously, resulted in survival rates of 5 and 0%, respectively, compared to 10% survival observed for saline-injected controls. Allopurinol at doses of 5 to 50 mg/kg per day had no effect on mouse survival. These data demonstrate the efficacy of superoxide dismutase for the protection of mice against hemorrhagic lung edema. The ineffectiveness of allopurinol suggests that the xanthine oxidase system does not play a major role in hemorrhage or lung edema and that caution is necessary when desferrioxamine is administered during an acute inflammatory process accompanied by erythrocyte lysis.
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