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Nakamura Y, Longueville S, Nishi A, Hervé D, Girault JA, Nakamura Y. Dopamine D1 receptor-expressing neurons activity is essential for locomotor and sensitizing effects of a single injection of cocaine. Eur J Neurosci 2021; 54:5327-5340. [PMID: 34273137 DOI: 10.1111/ejn.15394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 07/05/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022]
Abstract
Dopamine D1 receptors play an important role in the effects of cocaine. Here, we investigated the role of neurons which express these receptors (D1-neurons) in the acute locomotor effects of cocaine and the locomotor sensitization observed after a second injection of this drug, using the previously established two-injection protocol of sensitization. We inhibited D1-neurons using double transgenic mice conditionally expressing the inhibitory Gi-coupled designer receptor exclusively activated by designer drugs (Gi-DREADD) in D1-neurons. Chemogenetic inhibition of D1-neurons by a low dose of clozapine (0.1 mg/kg) decreased the cocaine-induced expression of Fos in striatal neurons. It diminished the basal locomotor activity and acute hyper-locomotion induced by cocaine (20 mg/kg). Clozapine 0.1 mg/kg had no effect by itself and did not alter cocaine effects in wild-type mice. Inhibition of D1-neurons during the first cocaine administration prevented the sensitization of the locomotor response in response to a second cocaine administration 10 days later. On Day 11, inhibition of D1-neurons by clozapine stimulation of Gi-DREADD blocked cocaine-induced locomotion including in sensitized mice, whereas on Day 12, in the absence of clozapine and D1-neurons inhibition, all mice displayed a sensitized response to cocaine. These results show that chemogenetic inhibition of D1-neurons decreases spontaneous and cocaine-induced locomotor activity. It prevents sensitization induction and blocks sensitized locomotion in a two-injection protocol of sensitization but does not reverse established sensitization. Our study further supports the central role of D1-neurons in mediating the acute locomotor effects of cocaine and its sensitization.
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Affiliation(s)
- Yukari Nakamura
- INSERM UMR-S 1270, Paris, France.,Faculty of Sciences and Engineering, Sorbonne University, Paris, France.,Institut du Fer à Moulin, Paris, France.,Department of Pharmacology, Kurume University School of Medicine, Kurume, Japan
| | - Sophie Longueville
- INSERM UMR-S 1270, Paris, France.,Faculty of Sciences and Engineering, Sorbonne University, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Akinori Nishi
- Department of Pharmacology, Kurume University School of Medicine, Kurume, Japan
| | - Denis Hervé
- INSERM UMR-S 1270, Paris, France.,Faculty of Sciences and Engineering, Sorbonne University, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Jean-Antoine Girault
- INSERM UMR-S 1270, Paris, France.,Faculty of Sciences and Engineering, Sorbonne University, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Yuki Nakamura
- INSERM UMR-S 1270, Paris, France.,Faculty of Sciences and Engineering, Sorbonne University, Paris, France.,Institut du Fer à Moulin, Paris, France
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