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Zhurakovskaya E, Leikas J, Pirttimäki T, Casas Mon F, Gynther M, Aliev R, Rantamäki T, Tanila H, Forsberg MM, Gröhn O, Paasonen J, Jalkanen AJ. Sleep-State Dependent Alterations in Brain Functional Connectivity under Urethane Anesthesia in a Rat Model of Early-Stage Parkinson's Disease. eNeuro 2019; 6:ENEURO.0456-18.2019. [PMID: 30838323 PMCID: PMC6399428 DOI: 10.1523/eneuro.0456-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra, leading to striatal dopamine depletion. A partial unilateral striatal 6-hydroxydopamine (6-OHDA) lesion causes 40-60% dopamine depletion in the lesioned rat striatum, modeling the early stage of PD. In this study, we explored the connectivity between the brain regions in partially 6-OHDA lesioned male Wistar rats under urethane anesthesia using functional magnetic resonance imaging (fMRI) at 5 weeks after the 6-OHDA infusion. Under urethane anesthesia, the brain fluctuates between the two states, resembling rapid eye movement (REM) and non-REM sleep states. We observed clear urethane-induced sleep-like states in 8/19 lesioned animals and 8/18 control animals. 6-OHDA lesioned animals exhibited significantly lower functional connectivity between the brain regions. However, we observed these differences only during the REM-like sleep state, suggesting the involvement of the nigrostriatal dopaminergic pathway in REM sleep regulation. Corticocortical and corticostriatal connections were decreased in both hemispheres, reflecting the global effect of the lesion. Overall, this study describes a promising model to study PD-related sleep disorders in rats using fMRI.
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Affiliation(s)
- Ekaterina Zhurakovskaya
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Juuso Leikas
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Tiina Pirttimäki
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Francesc Casas Mon
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Mikko Gynther
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Rubin Aliev
- Moscow Institute of Physics and Technology, 117303, Moscow, Russia
- Institute of Theoretical and Experimental Biophysics, 142292, Puschino, Russia
| | - Tomi Rantamäki
- Laboratory of Neurotherapeutics, Division of Pharmacology and Pharmacotherapeutics, Faculty of Pharmacy, University of Helsinki, Helsinki, FI-00790, Finland
| | - Heikki Tanila
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Markus M. Forsberg
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Olli Gröhn
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Jaakko Paasonen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, FI-70211, Finland
| | - Aaro J. Jalkanen
- School of Pharmacy, University of Eastern Finland, Kuopio, FI-70211, Finland
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Di Ciano P, Cormick PM, Stefan C, Wong E, Kim A, Remington G, Le Foll B. The effects of buspirone on occupancy of dopamine receptors and the rat gambling task. Psychopharmacology (Berl) 2017; 234:3309-3320. [PMID: 28825117 DOI: 10.1007/s00213-017-4715-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/04/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND The dopamine D3 receptor (DRD3) has been proposed as a target for drug development for the treatment of addictive disorders. Recently, the anxiolytic buspirone has been shown to have affinity for DRD3 and DRD4, and interest in repurposing it for addictive disorders has grown. METHODS Binding of [3H]-(+)-PHNO in the rat cerebellum and striatum was used to measure occupancy by buspirone of DRD3 or DRD2, respectively. Effects of buspirone in the rat gambling task (rGT) and the five-choice serial reaction time task (5-CSRTT) were examined. RESULTS Buspirone occupied both the DRD2 and DRD3 at high doses and the DRD3, but not the DRD2, in the narrow dose range of 3 mg/kg. At 10 mg/kg, a disruption of performance on rGT was observed. All measures of performance on the rGT, except for perseverations, were affected at 3 mg/kg. On the 5-CSRTT, omissions were increased. Impairments in the rGT were not mimicked by the effects induced by satiation. Further, buspirone did not impair food-maintained responding under a progressive ratio schedule of reinforcement at any dose, suggesting that the effects of buspirone on the rGT cannot be explained by non-selective actions. CONCLUSIONS Although buspirone had effects on the rGT at the dose that selectively occupied the DRD3, the effects found do not parallel those found in previous studies of the effects of selective DRD3 antagonists on the rGT. Thus, buspirone may impair performance on the rGT through actions at multiple receptor sites.
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Affiliation(s)
- Patricia Di Ciano
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
| | | | - Cristiana Stefan
- Clinical Laboratory and Diagnostic Services, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ernest Wong
- Clinical Laboratory and Diagnostic Services, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Aaron Kim
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
| | - Gary Remington
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada
- Addiction Medicine Service, Acute Care Program, CAMH, Toronto, ON, Canada
- CAMH, Campbell Family Mental Health Research Institute, Toronto, ON, Canada
- Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health (CAMH), University of Toronto, 33 Russell Street, Toronto, M5S 2S1, Canada.
- Addiction Medicine Service, Acute Care Program, CAMH, Toronto, ON, Canada.
- CAMH, Campbell Family Mental Health Research Institute, Toronto, ON, Canada.
- Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.
- Department of Pharmacology, University of Toronto, Toronto, ON, Canada.
- Division of Brain and Therapeutics, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
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Le Foll B, Payer D, Di Ciano P, Guranda M, Nakajima S, Tong J, Mansouri E, Wilson AA, Houle S, Meyer JH, Graff-Guerrero A, Boileau I. Occupancy of Dopamine D3 and D2 Receptors by Buspirone: A [11C]-(+)-PHNO PET Study in Humans. Neuropsychopharmacology 2016; 41:529-37. [PMID: 26089182 DOI: 10.1038/npp.2015.177] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 06/08/2015] [Accepted: 06/10/2015] [Indexed: 11/08/2022]
Abstract
There is considerable interest in blocking the dopamine D3 receptor (DRD3) versus the D2 receptor (DRD2) to treat drug addiction. However, there are currently no selective DRD3 antagonists available in the clinic. The anxiolytic drug buspirone has been proposed as a potential strategy as findings suggest that this drug has high in vitro affinity for DRD3, binds to DRD3 in brain of living non-human primate, and also disrupts psychostimulant self-administration in preclinical models. No study has explored the occupancy of DRD3 by buspirone in humans. Here, we used positron emission tomography (PET) and the D3-preferring probe, [(11)C]-(+)-PHNO, to test the hypothesis that buspirone will occupy (decreases [(11)C]-(+)-PHNO binding) the DRD3 more readily than the DRD2. Eight healthy participants underwent [(11)C]-(+)-PHNO scans after single oral dose administration of placebo and 30, 60, and 120 mg of buspirone in a single-blind within-subjects design. [(11)C]-(+)-PHNO binding in DRD2- and DRD3-rich areas was decreased by the highest (60-120 mg), but not the lowest (30 mg), doses of buspirone. The maximal occupancy obtained was ~25% in both areas. Plasma levels of prolactin (a DRD2 marker) correlated with percentage occupancy after orally administered buspirone. Self-reported dizziness and drowsiness increased after buspirone but that did not correlate with receptor occupancy in any region. Overall, the modest occupancy of DRD2 and DRD3 even at high acute doses of buspirone, yielding high levels of metabolites, suggests that buspirone may not be a good drug to preferentially block DRD3 in humans.
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