A. GIOVANNI1, S. ENGEL1, C. BOWEN1, R. TERRY-LORENZO1, P. G. JONES1, L. HARDY1, T. LARGE1, T. HANANIA2, E. V. SABATH2, V. ALEXANDROV2,3, M. QUTAISH3, M. SEAMAN3, P. CZARNECKI3, M. SILVA3, J. SULLIVAN3
1CNS, Sunovion Pharmaceuticals Inc, Marlborough, MA; 2PsychoGenics Inc., Tarrytown, NY; 3InviCRO LLC, Boston, MA
The objective of this study was to develop and test a method for screening the acute effect of test articles on 14C-2-deoxyglucose (14C-2DG) concentration in mouse brain, as a representation of glucose uptake due to compound-induced changes in neuronal activity. Eighty C57BL/6 mice were separated into 10 groups of 8 animals. After an overnight fast, each mouse was administered one of 10 test articles while awake via intraperitoneal (IP) injection. Five of the test articles were controls and included water (vehicle), Haloperidol, Desipramine, Ketamine, and Lithium Chloride. The other five test articles were Sunovion compounds in late stage discovery. Fifteen minutes after test article administration, each mouse was administered 14C-2DG intravenously (IV), also while awake. Mice were euthanized at 45 minutes post-injection of 14C-2DG, and their brains were harvested.
Each brain was halved sagittally along the midline and frozen. All 80 frozen brain halves were blocked together in a grid-like configuration for autoradiography. Sagittal 30-µm thick sections of the 80 brain halves were produced using a cryomacrotome. High resolution optical images were acquired prior to each section being taken from the block. Sections were exposed to phosphor imaging plates to measure radioactivity in the tissue and produce autoradioluminograms.
All 2D white light images and autoradioluminograms were reconstructed into 3D volumes. Individual 3D brain volumes were digitally extracted and all 80 brains (white light and autoradiography data) were registered to a common space. Qualitative comparisons and quantitative statistical parameters (vehicle vs. remaining test articles) were generated on the voxel-level and the region-level using the Allen brain atlas.
Changes in raw counts of radioactive signal produced patterns of responses in Regions of Interest (ROI’s) that relate test compounds (unknowns) to reference compounds used for the treatment of Schizophrenia (Haloperidoll), Depression (Desipramine), Treatment-Resistant Depression (Ketamine), and Bipolar Disorder (Lithium).
Comparisons of patterns of response and statistical analysis will be presented as they capture similarities and differences with respect to mouse ROIs’s of interest, brain circuits, and behavioral changes between known therapeutics for psychiatric indications and compounds in late stage discovery.