Dopamine Type-1 Receptor Binding in Major Depressive Disorder Assessed Using Positron Emission Tomography and [ C]NNC-112

The dopamine type-1 receptor has been implicated in major depressive disorder (MDD) by clinical and preclinical evidence from neuroimaging, post mortem , and behavioral studies. To date, however, selective in vivo assessment of D 1 receptors has been limited to the striatum in MDD samples manifesting anger attacks. We employed the PET radioligand, [ 11 C]NNC-112, to selectively assess D 1 receptor binding in extrastriatal and striatal regions in a more generalized sample of MDD subjects. The [ 11 C]NNC-112 nondisplaceable binding potential (BP ND ) was assessed using PET in 18 unmedicated, currently depressed subjects with MDD and 19 healthy controls, and compared between groups using MRI-based region-of-interest analysis. The mean D 1 receptor BP ND was reduced (14%) in the left middle caudate of the MDD group relative to control group ( p