Distinctive gene expression in brains of relapsing heroin-addicted rats

Aug 06, 2009

A group of genes whose expression is significantly altered following exposure to drug paraphernalia after an enforced 'cold-turkey' period have been identified. Researchers writing in the open access journal BMC Neuroscience studied gene expression in the brains of heroin-addicted rats, identifying those genes that may be involved in precipitating a relapse.

Kara Kuntz-Melcavage, from Pennsylvania State University College of Medicine, USA, is part of a team of researchers who carried out the experiments. She said, "A number of studies have investigated changes induced by , but few reports describe changes associated with the mental state that leads to relapse. We identified 66 genes involved in the relapse response, including some that are important for neuroplasticity, and through that role may impact learning and behavior".

Kuntz-Melcavage and her colleagues attached rats to a drug supply that for 3 hours each day delivered heroin into their jugular veins when they licked a particular empty spout. Over a two-week period, these animals were free to self-administer heroin, while control rats to whom they were linked received saline instead. One group of addicted rats and their yoked non-addicted partners were then kept without heroin for two weeks before being re-exposed to the spout, which no longer yielded drug infusions. After 90 minutes in this narcotic-associated environment, during which the addicted rats compulsively returned to lick the unrewarding empty spout, they and their yoked control mates were humanely killed and gene expression in their brains was studied.

By comparing the gene expression in the drug-seeking animals with that in a second group of addicted rats re-exposed to the narcotic environment after only one day of abstinence, and with the saline-yoked controls, the researchers were able to identify genes involved in relapse behavior. According to Kuntz-Melcavage, "The session with the inactive spout served not only to provide an opportunity to observe drug-seeking behavior, but also mimicked a real-life situation in which environmental cues precipitate relapse behavior following an extended period of abstinence".

Speaking about the results of the study, Kuntz-Melcavage said, "As data accumulate, the existence of a single 'relapse gene' is looking increasingly unlikely - it is likely to be a constellation of different genes. Therefore, large scale views of gene expression, like this one, will prove very useful for guiding research into human drug-associated behavior".

More information: Gene expression changes following extinction testing in a heroin behavioral incubation model; Kara L Kuntz-Melcavage, Robert M Brucklacher, Patricia S Grigson, Willard M Freeman and Kent E Vrana; BMC Neuroscience (in press); www.biomedcentral.com/bmcneurosci/

Source: BioMed Central (news : web)

Explore further: Study links enzyme to autistic behaviors

add to favorites email to friend print save as pdf

Related Stories

Hope for treating relapse to methamphetamine abuse

Nov 13, 2008

A new study at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory suggests that vigabatrin (a.k.a. gamma vinyl-GABA, or GVG) blocks drug-seeking behavior in animals previously trained to associate methamphetamine ...

Emotional 'bummer' of cocaine addiction mimicked in animals

Mar 12, 2008

Cocaine addicts often suffer a downward emotional spiral that is a key to their craving and chronic relapse. While researchers have developed animal models of the reward of cocaine, they have not been able to model this emotional ...

Recommended for you

Study links enzyme to autistic behaviors

19 hours ago

Fragile X syndrome (FXS) is a genetic disorder that causes obsessive-compulsive and repetitive behaviors, and other behaviors on the autistic spectrum, as well as cognitive deficits. It is the most common ...

A new cause of mental disease?

Jul 23, 2014

Astrocytes, the cells that make the background of the brain and support neurons, might be behind mental disorders such as depression and schizophrenia, according to new research by a Portuguese team from ...

Molecular basis of age-related memory loss explained

Jul 22, 2014

From telephone numbers to foreign vocabulary, our brains hold a seemingly endless supply of information. However, as we are getting older, our ability to learn and remember new things declines. A team of ...

The neurochemistry of addiction

Jul 22, 2014

We've all heard the term "addictive personality," and many of us know individuals who are consistently more likely to take the extra drink or pill that puts them over the edge. But the specific balance of ...

User comments : 0