Cocaine Changes The Brain To Create Cravings, Study Reveals

The effects of cocaine have been known to alter the way some genes are expressed, changing the structure and connectivity of the brain. The changes seen in the brain can lead to an intense craving for the drug. Now, a new study explained how drug addiction changes the brain in order to create cravings and how it can be a way to help to create new treatment.

Ben Taub wrote an article for iflscience.com that the changes caused by the effects of cocaine in the brain can result to the user's intense craving for the drug which can sometimes cause to recovering addicts' to relapse even after they have been clean. Up until now, scientists still can't figure out what causes these alterations, although they have already identified the protein that apparently settle the process.

Metro.co.uk reported that in order for researchers to replicate cocaine addiction in humans, they used lab rats to self-administer cocaine for six hours a day over a period of five days. After that, these rodents were then denied access to the drug for 14 to 30 days. During the rodents' detox phase, experts observed the lab rats' dopamine transporters that had returned to its pre-cocaine levels. However, as soon as the rats tried cocaine again, the single dose ended the 60-day abstinence and made the rodents' tolerance to the drug at its highest level of usage.

In a past study, it was revealed that a transcription factor called SMAD3 increases in those rats that are addicted to cocaine a week after they went through withdrawal. Transcription factors control genes to be expressed or not by interacting with certain proteins that remodel chromatin which are the genetic material that makes up chromosomes. Specifically, SMAD3 increases the expression of specific genes that control the formation of brain synapses in a part of the brain called the nucleus accumbens (NAc).

Since the nucleus accumbens is part of the brain's reward center, any changes that happen will most likely have a huge impact on behaviors that seeks rewards. Experts concluded that this is the reason why rodents continued to administer cocaine by themselves even after they were not in withdrawal anymore. To understand more about how SMAD3 increases the revelation of certain genes related to cocaine use, the team used chromatin immunoprecipitation techniques to observe which proteins the transcription factor connect with in these lab rats, independent.co.uk reported.

The results, published in the journal Biological Psychiatry, revealed that a chromatin remodeler known as BRG1 is not solely increased by the onset of cocaine addiction. This also happens when it interacts with SMAD3. Particularly, BRG1 attaches to the promoter regions of specific genes to be expressed by SMAD3. And because there are a lot of these genes functions to create synapses in the NAc, it is said that the interaction is also part of the reason why rats in the study go through cocaine.

It was also reported in iflscience.com that the team of scientists injected the rats with a different chemicals that block BRG1, to confirm the study. They found that these chemicals eliminated the rats' cravings for cocaine. After that they contaminated the rats with a virus that influenced the increased production of BRG1 which led to more cocaine cravings for the rats. The study did not only show how cocaine can change the brain in order to create cravings, but also showed possible areas to explore for new drug treatments by eliminating BRG1 which will stop to differet addictive tendencies.