The Addiction Research Group led by Steven Laviolette of the Schulich School of Medicine & Dentistry was able to identify how exposure to heroin induces a specific switch in a memory molecule in a region of the brain called the basolateral amygdala, which is involved importantly in controlling memories related to opiate addiction, withdrawal, and relapse. Using a rodent model of opiate addiction, Laviolette's team found that the process of opiate addiction and withdrawal triggered a switch between two molecular pathways in the amygdala controlling how opiate addiction memories were formed. In the non-dependent state, they found that a molecule called extracellular signal-related kinase or "ERK" was recruited for early stage addiction memories. However, once opiate addiction had developed, the scientists observed a functional switch to a separate molecular memory pathway, controlled by a molecule called calmodulin-dependent kinase II or "CaMKII".
"These findings will shed important new light on how the brain is altered by opiate drugs and provide exciting new targets for the development of novel pharmacotherapeutic treatments for individuals suffering from chronic opiate addiction," says Laviolette, an associate professor in the Departments of Anatomy & Cell Biology, Psychiatry, and Psychology.