Alterations in beta-adrenergic receptor binding in partially and fully amygdala-kindled juvenile and adult rats

Twenty-eight-day-old (juvenile) rats were kindled with hourly stimulations to partial or fully kindled status. Adult rats were stimulated with hourly or daily stimulations. Alterations in [3H]dihydroalprenolol binding were determined 3 weeks after the last stimulation. We found that partially kindled, hourly stimulated juvenile rats showed a significant increase in the dissociation constant (Kd), with no change in maximal binding values. Fully kindled juvenile rats showed no change in Kd or Bmax. Partially kindled, hourly stimulated adult rats showed a significant decrease in Kd, with no change in Bmax. There was no change in Kd or Bmax values in fully kindled, hourly stimulated adult rats. Fully kindled, daily stimulated adult rats showed a decrease in maximal binding, with no change in Kd values. These findings indicate that kindling-induced beta-adrenergic receptor alterations were influenced by the age of the animal and the kindling parameters used, as well as the extent to which the animals were kindled.