Drug abuse continues to damage millions of lives annually. While the popularity of different drugs rise and fall over time, once a drug is developed and makes it into the illegal drug market, it really never goes away. Although cocaine use appears to be on the decline over the past few years, trend data from the National Institute on Drug Abuse shows that 1.4 million Americans currently use this dangerous drug. Cocaine gives users a feeling of euphoria combined with a burst of energy, but it is also highly addictive and potentially lethal. The physical effects of taking cocaine include increased heart rate and blood pressure, which leads to an increased risk of heart attack and stroke. Repeated use of cocaine leads to addiction and other severe health related problems.
Uncovering the Genetic Roots of Addiction
Researchers from the Icahn School of Medicine at Mount Sinai have now identified a molecular mechanism that is involved in the development of cocaine addiction. It has been understood for some time that addiction is characterized by changes in the brain, particularly in the system that rewards pleasurable behavior and pushes an individual to repeat certain experiences. Cocaine hijacks this system and makes its users crave more of the drug to keep experiencing the same effect.
The Mount Sinai researchers identified an enzyme in laboratory mice that increases significantly levels after continued cocaine use. The enzyme is called PARP-1, and the higher levels of it caused by chronic cocaine use lead to changes in how genes are expressed in the nucleus accumbens, a section of the brain that plays a central role in the brain’s reward circuitry. PARP-1 does not literally change DNA, but, like other enzymes, it has the ability to activate or repress certain genes. This alters the pattern of activity in the nucleus accumbens and leads to changes in behavior—in this case, continued use of cocaine in order to keep experiencing the associated high.
The study at Mount Sinai shows that changing the level of PARP-1 in the brain can influence cocaine’s rewarding and addictive effects. Preventing PARP-1 from affecting the expression of genes in the nucleus accumbens could reduce the addictive power of cocaine.
New Directions for Treatment
Discovering this physical mechanism, which underlies cocaine addiction, suggests new approaches to treating such addiction by developing therapeutic drugs to inhibit the physical effects of cocaine use. It is possible that a PARP inhibitor could help cocaine addicts recover from their addiction more easily by preventing or reversing the brain changes that cause the addiction in the first place. This has not yet been proven as a treatment method, but researchers continue to study the possibility.
This study also suggests potential areas of research for treating other drug addictions. If other drugs are shown to involve PARP-1, a therapeutic drug that modifies its effects could also work to reduce addictions to other drugs as well. The research is very promising not only for people suffering from cocaine addiction, but also those struggling with addiction to other substances as well.
There isn’t yet enough data to show with any certainty whether therapeutic drug regimens can be developed to counter the effects of drug use – cocaine or other drugs – and to help addicts recover. This study appears to show some promise, however, that if science can identify the specific brain changes involved in addiction then specific therapies can be developed to counter them.