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Relapsing into drug taking is a big problem in treating addiction, where the majority of addicts return to drug-taking within 1 year of quitting. Addiction relapse is associated with drug-related cues such as places, drug paraphernalia, the drug itself, or stress, highlighting that memories play a key role in addiction relapse.
In this study researchers at Bath, working with colleagues from the University of Surrey and RenaSci, used an animal model to study relapse to morphine seeking behaviour. Rats or mice learned to associate particular environmental cues with morphine. After removal of the drugs, relapse back to drug-seeking behaviour occurred in response to getting the cues again.
They tested the effect of a blocker of a specific receptor for acetylcholine – the alpha7 nicotinic receptor – to see if this might impair relapse. This drug, methyllycaconitine (MLA), that comes from Delphinium plants, selectively blocked morphine relapse (but not the initial learning to seek drugs), in both mice and rats. The hippocampus is responsible for memory and the ventral domain is particularly associated with emotional memories, an obvious link to addiction pathways.
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