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Fanarioti E, Mavrikaki M, Panagis G, Mitsacos A, Nomikos GG, Giompres P. Behavioral and neurochemical changes in mesostriatal dopaminergic regions of the rat after chronic administration of the cannabinoid receptor agonist WIN55,212-2. Int J Neuropsychopharmacol 2014; 18:pyu097. [PMID: 25522428 PMCID: PMC4438542 DOI: 10.1093/ijnp/pyu097] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 11/14/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The endocannabinoid system interacts extensively with other neurotransmitter systems and has been implicated in a variety of functions, including regulation of basal ganglia circuits and motor behavior. The present study examined the effects of repeated administration of the nonselective cannabinoid receptor 1 agonist WIN55,212-2 on locomotor activity and on binding and mRNA levels of dopamine receptors and transporters and GABAA receptors in mesostriatal dopaminergic regions of the rat. METHODS Rats received systemic injections of WIN55,212-2 (0, 0.1, 0.3, or 1mg/kg, intraperitoneally) for 20 consecutive days. Locomotor activity was measured on days 1, 10, and 20. Following the last measurement, rats were euthanized and prepared for in vitro binding and in situ hybridization experiments. RESULTS Acutely, 0.3 and 1mg/kg of WIN55,212-2 produced hypolocomotion, which was sustained for the next 2 measurements, compared to vehicle. Repeated administration of WIN55,212-2 decreased the mRNA levels of the D2 autoreceptors in substantia nigra and ventral tegmental area and increased D1 receptor mRNA and binding in nucleus accumbens. Furthermore, both dopamine receptor and transporter binding and mRNA levels were decreased in substantia nigra. Moreover, repeated administration of WIN55,212-2 decreased GABAA receptor binding levels in dorsal striatum and substantia nigra. CONCLUSIONS Our data indicate that chronic WIN55,212-2 administration results in sustained effects on locomotor activity, similar to those observed after acute administration, and modulates the dopaminergic and GABAergic systems in a region-, dose-, and neurotransmitter-selective manner.
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MESH Headings
- Animals
- Basal Ganglia/drug effects
- Basal Ganglia/metabolism
- Behavior, Animal/drug effects
- Benzoxazines/administration & dosage
- Benzoxazines/pharmacology
- Cannabinoid Receptor Agonists/administration & dosage
- Cannabinoid Receptor Agonists/pharmacology
- Dopamine Plasma Membrane Transport Proteins/genetics
- Dopamine Plasma Membrane Transport Proteins/metabolism
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Dose-Response Relationship, Drug
- Injections, Intraperitoneal
- Male
- Morpholines/administration & dosage
- Morpholines/pharmacology
- Motor Activity/drug effects
- Naphthalenes/administration & dosage
- Naphthalenes/pharmacology
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, GABA-A/genetics
- Receptors, GABA-A/metabolism
- Time Factors
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Affiliation(s)
- Eleni Fanarioti
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Maria Mavrikaki
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - George Panagis
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Ada Mitsacos
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - George G Nomikos
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos)
| | - Panagiotis Giompres
- University of Patras, Department of Biology, Laboratory of Human and Animal Physiology, Patras, Greece (Drs Fanarioti and Giompres); University of Crete, Department of Psychology, Laboratory of Behavioral Neuroscience, Rethymno, Crete, Greece (Drs Mavrikaki and Panagis); University of Patras, Department of Medicine, Laboratory of Physiology, Patras (Dr Mitsacos); Takeda Development Center Americas Inc., Deerfield, IL (Dr Nomikos).
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Gervais J, Rouillard C. Dorsal raphe stimulation differentially modulates dopaminergic neurons in the ventral tegmental area and substantia nigra. Synapse 2000; 35:281-91. [PMID: 10657038 DOI: 10.1002/(sici)1098-2396(20000315)35:4<281::aid-syn6>3.0.co;2-a] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The serotoninergic (5-HT) input from the dorsal raphe nucleus (DRN) to midbrain dopamine (DA) neurons is one of the most prominent. In this study, using standard extracellular single cell recording techniques we investigated the effects of electrical stimulation of the DRN on the spontaneous activity of substantia nigra pars compacta (SNpc) and ventral tegmental area (VTA) DA neurons in anesthetized rats. Poststimulus time histograms (PSTH) revealed two different types of response in both SNpc and VTA. Some cells exhibited an inhibition-excitation response while in other DA neurons the initial response was an excitation followed by an inhibition. In SNpc, 56% of the DA cells recorded were initially inhibited and 31% of the DA cells were initially excited. In contrast, 63% of VTA DA cells were initially excited and 34% were initially inhibited. Depletion of endogenous 5-HT by the neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), and the 5-HT synthesis inhibitor para-chlorophenylalanine (PCPA), almost completely eliminated the inhibition-excitation response in both SNpc and VTA DA cells, without changing the percentage of DA cells initially excited. Consequently, the proportion of DA neurons that were not affected by DR stimulation increased after 5-HT depletion (from 13% to 60% in SNpc and from 6% to 31% in VTA). In several DA cells, DRN stimulation caused important changes in firing rate and firing pattern. These data strongly suggest that the 5-HT input from the DRN is mainly inhibitory. It also suggests that 5-HT afferences modulate SNpc and VTA DA neurons in an opposite manner. Our results also suggest that non-5-HT inputs from DR can also modulate mesencephalic DA neurons. A differential modulation of VTA and SNpc DA neurons by 5-HT afferences from the DRN could have important implications for the development of drugs to treat schizophrenia or other neurologic and psychiatric diseases in which DA neurons are involved.
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Affiliation(s)
- J Gervais
- Département de Médecine, Université Laval, Ste-Foy, Québec, Canada G1V 4G2
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