Involvement of corticosteroids in acoustic induction of audiogenic seizure susceptibility in mice

Genetically seizure-resistant C57BL/6 mice were induced to develop high susceptibility (90%) to audiogenic seizures by prior exposure to auditory stimulation (acoustic priming) on day 19 of age. The administration of metopyrone (MP) or aminoglutethimide (AG), two inhibitors of adrenal corticosteroid synthesis, at 5 hrs before acoustic priming, prevented the induction of seizure susceptibility. 11-Deoxy-17-hydroxycorticosterone, an antagonist of glucocorticoid action by blocking glucocorticoid receptors, was also effective in completely preventing the priming effect. Similarly, acoustic priming failed to induce audiogenic seizure susceptibility in adrenalectomized mice. When MP or AG was administered to primed mice at 5 hrs before testing for audiogenic seizures on day 28 of age, they did not affect the elicitation of seizures by sound stimulus in the already susceptible mice. These results indicate that corticosteroids are required in order for the acoustic induction of audiogenic seizure susceptibility to occur.