Experts at Baylor College of Medicine say that cocaine use can have toxic effects on brain cells (neurons) that produce dopamine, they found 16 percent fewer dopamine cells in the brains of cocaine users.

Using brain tissue acquired from deceased subjects, researchers microscopically compared the number of dopamine cells in the brains of 10 cocaine users to those in the brains of nine people matched for age who did not use the drug.

"Although we have always known that cocaine is a dangerous drug, for the first time we can now physically see that dopamine cells are lost in the brains of cocaine users," said Dr. Karley Little. Associated measures indicated that the loss of cells was recent and the subjects were not born with this loss.

"Dopamine plays a big role in the awareness of pleasurable things in the environment, including food and sex. The lack of dopamine cells may make a person less responsive to natural rewards, whether it's in the workplace or in a relationship."

The lack of dopamine cells could also lead to withdrawal or depression symptoms. Although effects of cocaine use vary among users, the study shows the potential dangers of this drug. Cocaine use may theoretically increase the risk of Parkinson's Disease, but the mechanisms involved may be different and not occur in the same individuals.

"This is just the beginning of the story. We can now create a model to understand the biochemistry involved, such as how cocaine is toxic and why it is more toxic in some than others." Previous work by Little indicated that dopamine uptake is increased by cocaine exposure in the same individuals, which might have contributed to the toxic effects.
References:
1. Karley Y. Little. Decreased brain dopamine cell numbers in human cocaine users. doi:10.1016/j.psychres.2008.10.034.
2. Image by Gjennomsiktig.