Chronic cocaine use triggers changes in brain's neuron structure

Chronic exposure to cocaine reduces the expression of a protein known to regulate brain plasticity, according to new, in vivo research on the molecular basis of cocaine addiction. That reduction drives structural changes in the brain, which produce greater sensitivity to the rewarding effects of cocaine.

The finding suggests a potential new target for development of a treatment for cocaine addiction. It was published last month in Nature Neuroscience by researchers at the University at Buffalo and Mount Sinai School of Medicine.

"We found that chronic cocaine exposure in mice led to a decrease in this protein's signaling," says David Dietz, PhD, assistant professor of pharmacology and toxicology in the School of Medicine and Biomedical Sciences, who did the work while at Mt. Sinai. "The reduction of the expression of the protein, called Rac1, then set in motion a cascade of events involved in structural plasticity of the brain -- the shape and growth of neuronal processes in the brain. Among the most important of these events is the large increase in the number of physical protrusions or spines that grow out from the neurons in the reward center of the brain.