Release of a growth factor in the nucleus accumbens - a brain area mediating reward - is necessary for the development and relapse of cocaine addiction, reports a paper in the August 2007 issue of Nature Neuroscience.
Addictive drugs are thought to 'hijack' reward systems in the brain, causing neurons to be persistently more responsive to drug-associated cues and stressors. David Self and colleagues report that four hours after cocaine self-administration, rats show an increase in brain-derived neurotrophic factor (BDNF) in the nucleus accumbens. Preventing this increase in BDNF reduced cocaine self-administration and the propensity to relapse, whereas giving the rats daily BDNF injections after cocaine self-administration increased cocaine-seeking behaviour and relapse. Moreover, using mice that were genetically engineered to lack BDNF only in the nucleus accumbens in adulthood, they showed that BDNF release in the nucleus accumbens did not affect the initial rewarding effects of cocaine, but did dramatically alter the development of addiction. If similar mechanisms mediate addiction in humans, these results could suggest possible approaches to addiction treatment.
David Self (University of Texas Southwestern Medical Center, Dallas, TX, USA)
Additional contact for comment on paper:
Geoffrey Schoenbaum (University of Maryland School of Medicine, Baltimore, MD, USA)
Abstract available online.
(C) Nature Neuroscience press release.
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