Blocking Drug-Related Memories May Prevent Relapses (HealthDay)

WEDNESDAY, Aug. 13 (HealthDay News) -- It may be possible toprevent a drug addiction relapse by disrupting the brain's attempts toretrieve drug-associated memories, according to new research.

U.K. researchers reduced drug-seeking behaviors in rats by blockingtheir brain's NMDA-type glutamate receptor, which is vital for learningand memory, during the recall of drug-associated memories. Researchershave known that recalling memories linked to previous drug use, such asenvironmental cues, can cause recovering drug addicts to relapse.

The findings are published in the Aug. 13 issue of The Journal ofNeuroscience.

In the study, researchers at the University of Cambridge trained ratsto associate a light going on with receiving a dose of cocaine. They"reactivated" the memory by exposing the rats to the light without thecocaine infusion. Later, the rats continued to perform behaviors thatturned on the light or learned to perform new behaviors to try to get morecocaine.

The rats' cocaine-seeking behaviors were reduced after the researchersgave the animals a chemical that interfered with the NMDA-type glutamatereceptor. When the single treatment was given just prior to thereactivation session, it reduced or even stopped drug-seeking behavior forup to a month; however, when given after or without the reactivationsession, it had no effect on subsequent drug-seeking behaviors.

The findings suggest combining existing therapy with properly timed useof NMDA receptor inhibitors may help addicts kick their habits. The U.S.Food and Drug Administration already has approved several NMDA receptorinhibitors, including the cough suppressant dextramethorphan and theAlzheimer's disease drug memantine.

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