The role of the beta adrenergic receptor subtype in the development and expression of kindled seizures was examined in vivo. Male Wistar rats received acute administrations of isoproterenol, a beta receptor agonist, or propranolol, a beta receptor antagonist, in doses of 0.5, 1.0 or 10.0 mg/kg 30 minutes prior to each kindling trial.
Isoproterenol initially lowered seizure thresholds while decreasing AD durations. In addition, this agent exerted profound retardative effects upon the development of kindling to fully generalized convulsions. Conversely,
blockade of beta receptors with propranolol initially raised thresholds for seizure while exerting no effects on initial AD durations. Furthermore, animals treated with this drug progressed to fully generalized seizures more rapidly than isoproterenol-treated animals.
These results are interpreted as evidence that different subpopulations of beta-adrenergic receptors mediate different seizure-related effects at various stages in the development of kindled convulsions.