Adrenoceptors in acoustically primed audiogenic seizures

Abstract

Bibliography: pages [77]-86.The audiogenic seizure (AGS) is a convulsive seizure syndrome elicited through exposure to intense sound. Genetically AGS-resistant. C57BL/6J mice may be rendered seizure susceptible through an acoustic priming procedure. These experiments investigated a possible role for adrenoceptors in acoustically primed AGS. It was hypothesized that the sequelae of acoustic priming involve increases in the activity of excitatory alpha-1 and beta-1 adrenoceptors with a concurrent decrease in the activity of inhibitory alpha-2 receptors. These alterations in receptor activity may produce an imbalance between excitatory and inhibitory mechanisms which results in AGS susceptibility. These hypotheses were evaluated through the administration of selective adrenoceptor antagonists to primed C57BL/6J mice. Experiment 1 replicated the priming phenomenon. In Experiment 2, methoxyamine exerted proconvulsant effects across all stages of the seizure syndrome, and the higher doses resulted in diminished latencies to all stages. The alpha-1 antagonist prazosin exerted anticonvulsant effects on seizure incidence. The beta-1 antagonist atenolol also exerted anticonvulsant effects. The alpha-2 agonist yohimbine failed to exert proconvulsant effects and reduced seizure incidence to zero at higher doses. The results suggest that acoustically primed AGS in C57BL/6J mice may involve a significant increase in the activity of alpha-1 and beta-1 adrenoceptors. No support was found for a role of alpha-2 adrenoceptors in acoustically primed AGS.M.A. (Master of Arts