Naloxone reverses retrograde amnesia induced by electroconvulsive shock

Abstract

Transcorneal electroconvulsive shock (ECS) (15.0 mA, 60 Hz, 2 sec) caused retrograde amnesia for a shuttle avoidance task in rats. The effect was completely reversed by the concomitant posttraining administration of naloxone (0.2 or 0.4 mg/kg, ip). It had been shown previously that ECS releases β-endorphin and Met-enkephalin in the rat brain. The present findings are consistent with the hypothesis that the amnestic effect of ECS may be mediated, at least in part, by the release of endogenous opioid peptides; however, actions upon other neurochemical parameters, particularly upon other neurotransmitter systems, cannot be excluded from that effect.