US Researchers at NIDA report having identified a key brain mechanism, better explaining how and why cocaine addiction occurs.
Announced last week, January 7th 2009, government scientists at the National Institute on Drug Abuse (NIDA) said that the new discoveries about the root of cocaine addiction could lead to the development of new drug treatments.
In experiments with mice, scientists showed how cocaine affects the epigenetic process histone methylation. Prolonged cocaine use, they found, can cause permanent changes to the way certain genes turn on and off.
Epigenetic is a process that influences a gene’s expression or appearance without changing the underlying DNA sequence, causing the gene to behave, or express, itself differently.
Histone methylation is the modification of certain amino acids in a histone protein, or the protein around which a DNA strand wind, which essentially turns the DNA off.
Cocaine in the brain prevents the enzyme from shutting off genes in the pleasure circuits of the brain, heightening cravings for more cocaine.
Furthermore, scientists were able to reverse the effects by increasing the activity of that particular gene, completely reversing the effects of chronic cocaine use. As well, scientists reported that it is likely that this be the same process for other addictions, including alcohol addiction, thereby potentially leading to new, more effective, addiction treatments.
“This fundamental discovery advances our understanding of how cocaine addiction works,” Dr. Nora D. Volkow, director of NIDA, said via press release. “Although more research will be required, these findings have identified a key new player in the molecular cascade triggered by repeated cocaine exposure, and thus a potential novel target for the development of addiction medications.”
The findings also help to explain addiction’s long-term cravings and relapse despite periods of total abstinence.
Source: Business Week & Ottawa Citizen
