In a study to better understand how drugs of abuse, such as cocaine, form cellular memories that fuel compulsive behaviors, researchers say they have found a surprising culprit: astrocytes, a part of the glia class of brain support cells once thought to have no significant role in cognition or memory.
The study was published by Elsevier in the journal Biological Psychiatry.
Previously known as a “glue” that holds neurons together, astrocytes were shown in the study to respond to the presence of cocaine by promoting the formation of new synapses, the physical connection points between neurons. The drug-induced synaptic connections re-pattern the brain in ways that contribute to addiction.
For the study, researchers bred transgenic mice in which they could visualize calcium signals, used by astrocytes to communicate with other cells. Focusing on a region deep in the brain that has been associated with reward, learning and addiction, data showed astrocyte signaling was necessary for the formation of cocaine-induced synapses.
The researchers then conducted an experiment in which rats self-administered cocaine. The rats were divided into two groups: a control group and a group in which researchers blocked the formation of the cocaine-induced synapses. While the control group sought cocaine after withdrawal, the latter group of rats did not.
“Thus, these new synapses may constitute a unique set of neuronal substrates involved in cocaine-associated memories,” Yan Dong, PhD, professor of neuroscience and the University of Pittsburgh and the study’s senior author, said in a news release announcing the findings. “Our results provide an unexpected yet concrete target: glial-mediated synaptogenic signaling.”
Dong added that the findings suggest the manipulation of the synapses could represent a new path forward for the treatment of substance use disorders.