Addiction has long been thought to be a form of learning. In the past few years, molecular biologists have amassed chemical evidence to prove it, in the process generating new ideas for combating drug use.
Some of the most striking recent studies have examined the affinity between cocaine and glutamate, one of several chemical neurotransmitters that govern communication between nerve cells and are involved particularly with memory. For example, Stanislav R. Vorel and his colleagues at the Albert Einstein College of Medicine discovered that electrically stimulating the hippocampus, a brain structure central to memory and rich in glutamate, causes dependence relapse in rats formerly addicted to cocaine. Other researchers found that glutamate activates brain cells devoted to dopamine, a neurotransmitter associated with feelings of reward and pleasure. Indeed, the dopamine reward circuit in the brain has been regarded as the addiction pathway, commandeered not just by cocaine but by all addictive drugs. The fact that glutamate modifies dopamine action demonstrates a direct connection between brain reward circuits and those for learning and memory.
This article was originally published with the title Beating Abuse.