Research Presented by Christine DeLorenzo, PhD Provides New Tool in the Search for Fast-Acting Antidepressants

Christine DeLorenzo, PhD

June 5, 2014 - Christine DeLorenzo, PhD, Director of the Center for Understanding Biology using Imaging Technology (CUBIT), delivered a presentation titled “Imaging ketamine-induced changes using Positron Emission Tomography and [11C]ABP688” at the 10th International Symposium
 on Functional NeuroReceptor Mapping of the Living Brain on May 23, 2014, in Amsterdam.

Dr. DeLorenzo reported on research that she and colleagues at Columbia University and Yale University conducted to determine the utility of the radioligand [11C]ABP688 for imaging the acute effect of the drug ketamine on a neurotransmitter receptor — brain metabotropic glutamatergic receptor subtype 5, referred to as mGluR5. Recent research has shown that ketamine can induce a rapid antidepressant effect which can last for several days in people with treatment-resistant depression, touching off an intense search for the mechanisms of ketamine’s antidepressant capacities. Pharmacological studies have suggested that mGluR5 may play a role.

In the study presented by Dr. DeLorenzo, ten healthy volunteers participated in two PET scans on the same day — one before receiving an injection of ketamine and one while the ketamine was being injected. For each scan, the volunteers received an injection of [11C]ABP688, which is known to have a specific affinity for mGluR5. When PET emission data were collected and analyzed, Dr. DeLorenzo and her colleagues observed a significant reduction in the estimated distribution volume of [11C]ABP688 after the injection of ketamine. This finding suggests that [11C]ABP688 binding is sensitive to the changes in brain neurochemistry induced by ketamine, making it a potentially valuable tool in the search for a fast-acting and long-lasting antidepressant.