Convulsions induced by canatoxin in rats are probably a consequence of hypoxia

Canatoxin, a convulsant neurotoxin from the seeds of Canavalia ensiformis, induces lipoxygenase-dependent hypoxia and sex-related alterations of carbohydrate metabolism in rats which are blocked by glucose, diazepam and hexamethonium. The present study analyzes the possible casual relationship between the convulsant action of canatoxin and its effects on carbohydrate metabolism. The incidence of canatoxin-induced convulsions was greater in male than in female rats. Pretreatment of male rats with drugs that block hypoxia, such as glucose (2.5 g/kg, iv, 15 min), diazepam (5 mg/kg, ip, at 48 h, 24 h and 15 min), hexamethonium (4 mg/kg, ip, 15 min) and NDGA (125 mg/kg, ip, 1 h), also protected the animals against convulsions, respiratory distress and death. These results suggest that canatoxin-induced convulsions are probably the consequence of hypoxia and both effects are mediated by lipoxygenase activation.