Potential new treatment for drug addiction relapse revealed

June 12, 2018

Research published in Addiction Biology by scientists at the University of Bath reveals a new potential mechanism for combatting drug addiction relapse.

Relapsing into drug taking is a big problem in treating addiction, where the majority of addicts return to drug-taking within 12 months of quitting. This is brought into focus by the burgeoning 'opioid epidemic' of prescription as well as recreational opioid drugs, such as morphine and heroin. 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.

The Bath team wanted to test the effect of using a blocker for a brain neurotransmitter called acetylcholine, which is involved in memory processes. 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.

This exciting novel observation led the researchers to investigate the brain region responsible for MLA's effect and identified the ventral hippocampus as the locus. The hippocampus is well known for its role in memory, and the ventral domain is particularly associated with emotional memories, an obvious link to addiction pathways.

Professor Sue Wonnacott, from the University of Bath's Department of Biology & Biochemistry, said: "It's an exciting step forward that links the cholinergic system, more commonly associated with nicotine addiction, with the mechanisms of relapse a different class of abused drug - the opioids. More work needs to be done to uncover the brain mechanisms involved, but it raises the prospect of erasing long-term drug-associated memories that underpin addiction and the propensity to relapse."

Dr Chris Bailey, from the University of Bath's Department of Pharmacy & Pharmacology, commented: "Drug addiction is very poorly treated at present so this potential novel approach is very welcome. An important next step is to see if MLA blocks relapse to other abused drugs. We already have evidence, in the same animal model, that it is effective against the more potent opioid, heroin. If MLA has similar effects against other drugs of abuse such as cocaine it would be even more encouraging."
-end-
The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and RenaSci.

The study is published in Addiction Biology and is available online, doi:10.1111/adb.12624

University of Bath

Related Memories Articles from Brightsurf:

Can sleep protect us from forgetting old memories?
Researchers at University of California San Diego School of Medicine report that sleep may help people to learn continuously through their lifetime by encoding new memories and protecting old ones.

Why are memories attached to emotions so strong?
Multiple neurons in the brain must fire in synchrony to create persistent memories tied to intense emotions, new research from Columbia neuroscientists has found.

False memories of crime appear real when retold to others
People are no better than chance at identifying when someone else is recounting a false or real memory of a crime, according to a new UCL study published in Frontiers in Psychology.

Can traumatic memories be erased?
Tokyo, Japan - Scientists from Tokyo Metropolitan University have discovered that Drosophila flies lose long-term memory (LTM) of a traumatic event when kept in the dark, the first confirmation of environmental light playing a role in LTM maintenance.

The way of making memories
How does the brain translate information from the outside world into something we remember?

A new discovery: How our memories stabilize while we sleep
Scientists at the Center for Interdisciplinary Research in Biology (CNRS/Coll├Ęge de France/INSERM) have shown that delta waves emitted while we sleep are not generalized periods of silence during which the cortex rests, as has been described for decades in the scientific literature.

How memories form and fade
Caltech researchers identify the neural processes that make some memories fade rapidly while other memories persist over time.

Firework memories
Recently Weizmann Institute scientists succeeded in recording these rapid bursts of activity -- called 'hippocampal ripples' -- in the human brain, and they were able to demonstrate their importance as a neuronal mechanism underlying the engraving of new memories and their subsequent recall.

Your nose knows when it comes to stronger memories
Memories are stronger when the original experiences are accompanied by unpleasant odors, a team of researchers has found.

Proof it's possible to enhance or suppress memories
Boston University neuroscientist Steve Ramirez and collaborators have published a new paper showing memories are pliable if you know which regions of the brain's hippocampus to stimulate, which could someday enable personalized treatment for people with PTSD, depression and anxiety.

Read More: Memories News and Memories Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.