Time-Dependent Disruption of Morphine Tolerance by Electroconvulsive Shock and Frontal Cortical Stimulation

Abstract
Electroconvulsive shock or frontal cortex stimulation administered to rats at 5 but not at 180 minutes after an initial administration of morphine sulfate disrupted the development of one-trial tolerance to the analgesic effects of morphine sulfate. It is suggested that development of tolerance may be mediated by cellular mechanisms and memory processes similar to those thought to underlie conventional learning.