Mechanism behind cocaine craving identified
A possible future way to prevent relapses into drug dependence has been discovered by researchers at Linköping University and the German cancer research center DKFZ. The target is the dopamine-producing nerve cells in the midbrain.
Earlier research has shown that these cells become more excitable when a person takes drugs. To find out the functional meaning of this, these researchers used a mouse model for cocaine dependence. When they blocked the cells’ receptors for glutamate–the brain’s most important signal substance–the risk of relapsing into addiction vanished.
The findings are being published in the highly ranked journal Neuron.
Dopamine-producing nerve cells are central to the brain’s reward system. Dependence-inducing drugs cause concentrations of dopamine to rise in the surroundings, which in turn affects other nerve cells and brings about various physical and mental reactions.
Cocaine has a very rapid impact on dopamine levels, which explains why it is one of the most addictive drugs.
“When you take cocaine, the number of glutamate receptors increases, rendering the cell more excitable. When we block this process, we prevent relapses into addiction. This is interesting clinically since that is the phase when we can get hold of patients,” says David Engblom, a neurobiologist at Linköping University and the study’s lead author.
An addict who wants to give up drugs could thus be offered a ‘vaccination’ against relapsing. But much more research remains to be done before such treatment can become a reality.
The article “Glutamate Receptors on Dopamine Neurons Control the Persistence of Cocaine-Seeking” by David Engblom et al. was published in Neuron on August 14.
Last updated: 2009-06-03