Mu opioid receptors in GABAergic neurons of the forebrain promote alcohol reward and drinking
| Autor: | Brigitte L. Kieffer, Pauline Charbogne, Sami Ben Hamida, Laura-Joy Boulos, Michael McNicholas |
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| Rok vydání: | 2017 |
| Předmět: |
Pharmacology
Medicine (miscellaneous) Striatum Biology Conditioned place preference 030227 psychiatry Ventral tegmental area 03 medical and health sciences Psychiatry and Mental health 0302 clinical medicine medicine.anatomical_structure nervous system mental disorders Forebrain polycyclic compounds medicine GABAergic Brain stimulation reward μ-opioid receptor human activities Neuroscience 030217 neurology & neurosurgery Endogenous opioid |
| Zdroj: | Addiction Biology. 24:28-39 |
| ISSN: | 1355-6215 |
| DOI: | 10.1111/adb.12576 |
| Popis: | Mu opioid receptors (MORs) are widely distributed throughout brain reward circuits and their role in drug and social reward is well established. Substantial evidence has implicated MOR and the endogenous opioid system in alcohol reward, but circuit mechanisms of MOR-mediated alcohol reward and intake behavior remain elusive, and have not been investigated by genetic approaches. We recently created conditional knockout (KO) mice targeting the Oprm1 gene in GABAergic forebrain neurons. These mice (Dlx-MOR KO) show a major MOR deletion in the striatum, whereas receptors in midbrain (including the Ventral Tegmental Area or VTA) and hindbrain are intact. Here, we compared alcohol-drinking behavior and rewarding effects in total (MOR KO) and conditional KO mice. Concordant with our previous work, MOR KO mice drank less alcohol in continuous and intermittent two-bottle choice protocols. Remarkably, Dlx-MOR KO mice showed reduced drinking similar to MOR KO mice, demonstrating that MOR in the forebrain is responsible for the observed phenotype. Further, alcohol-induced conditioned place preference was detected in control but not MOR KO mice, indicating that MOR is essential for alcohol reward and again, Dlx-MOR KO recapitulated the MOR KO phenotype. Taste preference and blood alcohol levels were otherwise unchanged in mutant lines. Together, our data demonstrate that MOR expressed in forebrain GABAergic neurons is essential for alcohol reward-driven behaviors, including drinking and place conditioning. Challenging the prevailing VTA-centric hypothesis, this study reveals another mechanism of MOR-mediated alcohol reward and consumption, which does not necessarily require local VTA MORs but rather engages striatal MOR-dependent mechanisms. |
| Databáze: | OpenAIRE |
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