A possible role for beta-adrenergic receptors in the expression of audiogenic seizures.

DBA/2 mice are genetically prone to audiogenic seizures and, when compared with seizure resistant C57BL/6 mice, were found to have an increased density of beta-adrenergic receptors in their midbrain at the age of peak seizure susceptibility. Propranolol, a beta-receptor blocking agent, attenuated all stages of the seizure syndrome. However, a comparison of the effects of its d- and l-isomers suggested that propranolol's anticonvulsant activity was due to its local anesthetic-like action. Pindolol, a more potent beta blocker that is at least 100 times less potent than propranolol with respect to local anesthetic-like activity, produced anticonvulsant effects in approximately the same systemic dose range as propranolol. This indicates that pindolol's anticonvulsant activity could be due to beta blockade and, taken together, these data suggest that beta-adrenergic receptors may play a role in the expression of audiogenic seizures in these animals.