Attenuation of amnesia by hydrocortisone in the mouse

Effects of hydrocortisone on the retrograde amnesia produced by electroconvulsive shock (ECS) was studied in 228 mice. The animals were given ECS after one-trial training in a step-through apparatus, and tested for passive avoidance behavior 7 days later. The amnesic effect of ECS was absent in the animals that were injected with hydrocortisone SC prior to the administration of ECS. Hydrocortisone alone, without ECS, had no significant effect on passive avoidance. There was no indication that the hormone suppressed the ECS-induced seizure activity in the brain. The results suggest that hydrocortisone protected the animals from amnesia by acting on the brain before the onset of the disruptive action of ECS.