Retrograde amnesia produced by electrical stimulation of the amygdala: attenuation with adrenergic antagonists.

Subseizure electrical stimulation of the amygdala produced retrograde amnesia for a visual discrimination shock-motivated task. Animals pretreated with the alpha-adrenergic antagonist phenoxybenzamine, or the beta-adrenergic antagonist propranolol, did not develop amnesia. The findings indicate that adrenergic antagonists attenuate amnesia produced by amygdala stimulation for visual discrimination training. These results are consistent with previous evidence indicating that adrenergic antagonists attenuate the amnesias produced by a variety of agents, and thus, suggest that adrenergic mechanisms may be involved in the production of retrograde amnesia.