Feature Finding Title
Feature Finding FigureSubclasses of GABA interneurons differentially influence cortical network activity. The contribution of differences in GABA synthesis and reuptake in axon boutons to cell type-specific functions is unknown. GABA is synthesized within boutons by GAD65 and GAD67, while GAT1 is responsible for GABA reuptake. Using an imaging methodology capable of determining the colocalization frequency of different immunocytochemical labels in the same bouton, and the quantification of the fluorescence intensity of each label in these same structures, we assessed the bouton levels of GAD65, GAD67, and GAT1 in parvalbumin expressing chandelier (PVch) and basket (PVb) neurons, and cannabinoid receptor 1 expressing basket (CB1rb) neurons in the monkey prefrontal cortex. We show that PVch boutons almost exclusively contained GAD67, relative to GAD65, whereas CB1rb boutons contained mostly GAD65. In contrast, both GAD65 and GAD67 were easily detected in PVb boutons (Figure). Furthermore, in comparison to PVch boutons, CB1rb boutons expressed low to undetectable levels of GAT1. Our findings provide a new basis for the distinctive functional roles of these perisomatic-innervating interneurons in cortical circuits. In addition, they strongly suggest that altered levels of GAD67 or GAD65, as seen in some psychiatric diseases, would have cell type-specific consequences on the modulation of GABA neurotransmission.

Fish KN, Sweet RA, Lewis DA: Differential distribution of proteins regulating GABA synthesis and reuptake in axon terminals of subpopulations of cortical interneurons. Cereb Cortex, ePub March 21, 2011.

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David A. Lewis, M.D. | Department of Psychiatry | University of Pittsburgh
3811 O'Hara Street, Biomedical Science Tower W1654
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