New Research Finds Potential Target For Cocaine Addiction Treatment
A study by researchers at Massachusetts General Hospital and the Perelman School of Medicine at the University of Pennsylvania could hugely improve treatment for cocaine addiction, as it claims to have found a potential target which would greatly improve treatment efficacy.
Their findings, published in Molecular Psychiatry, show evidence that changing a single amino acid in a subunit of an important receptor protein also can alter whether animals exposed to cocaine will resume drug seeking after a period of cocaine abstinence.
Increasing expression of the enzyme responsible for that change within the GluA2 subunits of AMPA receptors– which receive nerve impulses carried by the neurotransmitter glutamate– reduced cocaine seeking in animals allowed to self-administer the drug.
“The critical role of the AMPA receptor in cocaine addiction is clear,” said Ghazaleh Sadri-Vakili, director of the NeuroEpigenetics Laboratory in the MassGeneral Institute for Neurodegenerative Disease, senior author of the report. “We have known that activation of the AMPA receptor in the nucleus accumbens– an area of the brain important for drug addiction– promotes the resumption of cocaine seeking in animal models, and this study identifies an increased contribution of calcium-permeable AMPA receptors to this process.”
For the study, lead author Heath Scmidt, assistant professor of Psychiatry at the Perelman School of Medicine, first allowed a group of rats to self-administer cocaine over a period of 21 days, then withheld the substance from the test animals for a week. Bioscience Technology explains that examination of the animals’ brains after seven days of drug abstinence found that levels within the nucleus accumbens of both edited GluA2 and of the enzyme responsible for editing were reduced, compared with the brains of animals not exposed to cocaine, suggesting that activation of the receptors containing unedited FluA2 could potentially stimulate cocaine craving.
Sadri-Vakili, an assistant professor of Neurology at Harvard Medical School, explained: “Our findings support the novel hypothesis that calcium-permeable AMPA receptors containing unedited GluA2 subunits contribute to cocaine seeking and that repairing the deficient editing of GluA2, possibly by regulation of ADAR2 expression, could be a treatment strategy for cocaine addiction.”