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| Status |
Public on Feb 16, 2021 |
| Title |
Mesocorticolimbic circuit mechanisms underlying the effects of ketamine on dopamine: a translational imaging study |
| Organism |
Mus musculus |
| Experiment type |
Expression profiling by high throughput sequencing
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| Summary |
Patients with schizophrenia show increased striatal dopamine synthesis capacity in imaging studies. However, the mechanism underlying this is unclear but may be due to N-methyl-D-aspartate receptor (NMDAR) hypofunction and parvalbumin (PV) neuronal dysfunction leading to disinhibition of mesostriatal dopamine neurons. Here, we test this in a translational mouse imaging study using a ketamine model. Mice were treated with sub-chronic ketamine (30mg/kg) or saline followed by in-vivo positron emission tomography of striatal dopamine synthesis capacity, analogous to measures used in patients. Locomotor activity was measured using the open field test. In-vivo cell-type-specific chemogenetic approaches and pharmacological interventions were used to manipulate neuronal excitability. Immunohistochemistry and RNA sequencing were used to investigate molecular mechanisms. Sub-chronic ketamine increased striatal dopamine synthesis capacity (Cohen’s d=2.5) and locomotor activity. These effects were countered by inhibition of midbrain dopamine neurons, and by activation of cortical and ventral subiculum PV interneurons. Sub-chronic ketamine reduced PV expression in these neurons. Pharmacological intervention with SEP-363856, a novel psychotropic agent with agonism at trace amine receptor 1 (TAAR1), significantly reduced the ketamine-induced increase in dopamine synthesis capacity. These results show that sub-chronic ketamine treatment in mice mimics the dopaminergic alterations in patients with psychosis, and suggest an underlying neurocircuit involving PV interneuron hypofunction in frontal cortex and hippocampus as well as activation of midbrain dopamine neurons. A novel TAAR1 agonist reversed the dopaminergic alterations suggesting a therapeutic mechanism for targeting presynaptic dopamine dysfunction in patients.
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| Overall design |
Investigation of gene expression in the pre-limbic cortex in mice treated with sub-chronic ketamine or saline.
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| Contributor(s) |
Kokkinou M, Paul EJ, Irvine EE, Khadayate S, Ungless MA, Withers DJ, Howes OD |
| Citation(s) |
32382134 |
| |
| Submission date |
Oct 12, 2019 |
| Last update date |
Feb 16, 2021 |
| Contact name |
Sanjay Padmakar Khadayate |
| Organization name |
MRC London Institute of Medical Sciences
|
| Street address |
Du Cane Road
|
| City |
London |
| ZIP/Postal code |
W12 0NN |
| Country |
United Kingdom |
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| Platforms (1) |
| GPL17021 |
Illumina HiSeq 2500 (Mus musculus) |
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| Samples (6)
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| Relations |
| BioProject |
PRJNA577230 |
| SRA |
SRP225311 |
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