Obsessive-compulsive disorder (OCD) is a chronic, disabling condition with inadequate treatment options that leave most patients with substantial residual symptoms. Structural, neurochemical, and behavioral findings point to a significant role for basal ganglia circuits and for the glutamate system in OCD. Genetic linkage and association studies in OCD point to SLC1A1, which encodes the neuronal glutamate/aspartate/cysteine transporter EAAT3/EAAC1. Despite this, no previous studies have investigated EAAT3 in basal ganglia circuits or in relation to OCD-related behavior. Here, we report a new model of Slc1a1 loss based on an excisable STOP cassette that yields successful ablation of EAAT3 expression and function. Using amphetamine as a probe, we found that EAAT3 loss prevents expected increases in 1) locomotor activity, 2) stereotypy, and 3) immediate early gene induction in the dorsal striatum following amphetamine administration. Further, Slc1a1-STOP mice showed diminished grooming in an SKF-38393 challenge experiment, a pharmacologic model of OCD-like grooming behavior. This is accompanied by reduced D1 receptor binding in the dorsal striatum of Slc1a1-STOP mice. Slc1a1-STOP mice also exhibit reduced extracellular dopamine concentrations both at baseline and following amphetamine challenge in the dorsal striatum. Viral-mediated restoration of Slc1a1/EAAT3 expression in the midbrain but not in the striatum results in partial rescue of amphetamine induced locomotion and stereotypy in Slc1a1-STOP mice, consistent with an impact of EAAT3 loss on pre-synaptic dopaminergic function. Collectively, these findings represent the first indication that the most consistently associated OCD candidate gene impacts basal ganglia-dependent repetitive behaviors.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-05232017-122303 |
| Date | 26 May 2017 |
| Creators | Zike, Isaac Daniel |
| Contributors | Carrie Jones, James Bodfish, Ariel Deutch, Gregg Stanwood, Jeremy Veenstra-VanderWeele |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-05232017-122303/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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