Retrograde amnesia produced by several treatments: evidence for a common neurobiological mechanism.

This experiment examined the effects on memory of various amnestic treatments in animals earlier treated with the alpha-adrenergic antagonist phenoxybenzamine (PBZ). Thirty minutes before being trained in a one-trial inhibitory (passive) avoidance task, animals received an injection of PBZ or saline. Immediately after training, each animal received one of the following amnestic treatments: stimulation of the frontal cortex or amygdala, pentylenetetrazol, diethyldithiocarbamate, or cycloheximide. In control animals, each treatment produced retrograde amnesia. However, PBZ-treated animals did not develop amnesia. These findings suggest that there may be a common neurobiological mechanism underlying the amnesias produced by many treatments.