Cocaine may kill brain's pleasure centers

BY ADHIRAJ DUTT
Daily Staff Reporter
Published January 14, 2003

A University team of researchers has found that cocaine use may harm or kill the same brain cells that produce dopamine, the pleasure centers of the brain that allow users to feel a "high" from the drug.

The researches said that this finding may explain why cocaine users have to continue increasing the amount of cocaine they use to get the same high, which strengthens their dependency on the drug.

Taking brain samples from 35 deceased cocaine users and from 35 non-drug users, an interdisciplinary researcher team studied the effects of cocaine on the brain by examining dopamine-releasing brain cells from the samples.

In decreased concentrations, dopamine has been associated with Parkinson's disease.

"Dopamine finds its way to receptors on neighboring cells, triggering signals that help set off pathways to different feelings or sensations," the study says.

Results also indicate that cocaine creates a high by trapping dopamine between receptors in the brain sending the pleasure signal repeatedly.

"When first taken, cocaine has a disruptive effect on the brain's dopamine system. It blocks the transporters that return dopamine to its home cell once its signaling job is done," according to the team's written statement. "With nowhere to go, dopamine builds up in the synapse and keeps binding with other cells' receptors, sending pleasure signals over and over again. This helps cause the intense 'high' cocaine users feel."

Collecting data for nearly seven years, the team performed a series of studies in the attempt to discover what exactly cocaine does to the users' brains.

"Chronic users have a depleted supply of dopamine and we found that the depressed users had the biggest changes in supply," Karley Little, one of the study's authors, said. "We now are wondering whether the effects are reversible."

In order to make the public aware of their findings, the researchers published a paper in the January issue of the American Journal of Psychiatry that recieved substantial media attention.

Though the study's impact on cocaine users has not yet been determined, it is expected that not all users will change their cocaine habits. "It seems to me that the study has a lot to do with tolerance," a cocaine user who wished to be anonymous said. "Reading it wouldn't affect my cocaine use. Because of my tolerance, I would just do more of it at a time so that it would have an equal effect.

Most people know that drugs are bad for them before they do them, but there are worse things. As long as you know your cocaine is pure and not dirty, it is alright," the person added.

According to Little, most cocaine users are trying to quit, but he hopes that the latest findings will prevent people from using the drug in the first place.

"When I started using cocaine, I knew it was bad for me, but I didn't know how exactly," another cocaine user who wished to remain anonymous said. "I didn't know that I was killing the very brain cells that were allowing me to feel cocaine's effect. If I did, I probably wouldn't have started."