D1 receptor hypersensitivity in mice with low striatal D2 receptors facilitates select cocaine behaviors
| Autor: | Roland Bock, Lindsay Eberhart, J. Hoon Shin, Khanhky Phamluong, Veronica A. Alvarez, Lauren K. Dobbs, Alanna R Kaplan, Dorit Ron, Miriam E. Bocarsly |
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| Rok vydání: | 2018 |
| Předmět: |
Agonist
MAPK/ERK pathway Male medicine.drug_class Drug-Seeking Behavior Down-Regulation Self Administration Striatum Article 03 medical and health sciences Mice 0302 clinical medicine Dopamine receptor D1 Downregulation and upregulation Cocaine Dopamine receptor D2 Medicine Animals Receptor Pharmacology Mice Knockout Central Nervous System Sensitization Dose-Response Relationship Drug business.industry Receptors Dopamine D2 Receptors Dopamine D1 Benzazepines Synaptic Potentials 16. Peace & justice Corpus Striatum 030227 psychiatry Psychiatry and Mental health nervous system Female business Self-administration Neuroscience 030217 neurology & neurosurgery Locomotion |
| Zdroj: | Neuropsychopharmacology |
| ISSN: | 1740-634X |
| Popis: | Vulnerability for cocaine abuse in humans is associated with low dopamine D2 receptor (D2R) availability in the striatum. The mechanisms driving this vulnerability are poorly understood. In this study, we found that downregulating D2R expression selectively in striatal indirect-pathway neurons triggers a multitude of changes in D1 receptor (D1R)-expressing direct-pathway neurons, which comprise the other main subpopulation of striatal projection neurons. These changes include a leftward shift in the dose-response to a D1-like agonist that indicates a behavioral D1R hypersensitivity, a shift from PKA to ERK intracellular signaling cascades upon D1R activation, and a reduction in the density of bridging collaterals from D1R-expressing neurons to pallidal areas. We hypothesize that the D1R hypersensitivity underlies abuse vulnerability by facilitating the behavioral responses to repeated cocaine, such as locomotor sensitization and drug self-administration. We found evidence that littermate control mice develop D1R hypersensitivity after they are sensitized to cocaine. Indeed, D1-like agonist and cocaine cross-sensitize in control littermates and this effect was potentiated in mice lacking striatal D2Rs from indirect-pathway neurons. To our surprise, mice with low striatal D2Rs acquired cocaine self-administration similarly to littermate controls and showed no significant change in motivation to take cocaine but lower seeking. These findings indicate that downregulation of striatal D2Rs triggers D1R hypersensitivity to facilitate cocaine locomotor sensitization, which by itself was not associated with greater cocaine taking or seeking under the conditions tested. |
| Databáze: | OpenAIRE |
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