Cells contain organelles called mitochondria that act as tiny powerhouses; scientists have known for many years mitochondria in the neurons of the brain are linked to brain disorders such as anxiety, the response to stress, bipolar disorder, and depression. Now, research by investigators at the University of Maryland School of Medicine (UMSOM) has found that in the cocaine-addicted state, mitochondrial changes take place in the brain. The scientists have also been able to prevent those alterations. This research has been published in Neuron.
The researchers used a mouse model that was repeatedly exposed to cocaine, and in those animals, the levels of a molecule that functions in a process called mitochondrial fission were found to be increased in the brain’s reward region. A chemical called Mdivi-1, a drug that blocks mitochondrial division, was used by the investigators to stop this change from happening. In addition, by genetic manipulating the fission molecule in mitochondria of brain cells, the scientists were able to block the response to cocaine.
"We are actually showing a new role for mitochondria in cocaine-induced behavior, and it's important for us to further investigate that role," said Mary Kay Lobo, Ph.D., an Associate Professor of Anatomy and Neurobiology at UMSOM.
After analyzing the mitochondria in mice that were given cocaine and finding the increase in fission, or mitochondrial division, in the major reward center of the brain, the work moved to humans. By assessing tissue harvested from postmortem individuals who had been dependent on cocaine, the researchers were able to confirm these alterations in the mitochondrial fission molecule in people.
Dr. Lobo noted that this latest study might be beneficial to researchers aiming to understand the changes that occur in brain cells and mitochondria because of other addictive disorders. "We are interested to see if there are mitochondrial changes when animals are taking opiates. That is definitely a future direction for the lab," she concluded.
Learn more about the biochemical effects that cocaine has on the brain from the video above, from the National Institute on Drug Abuse.