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Aversive Stress Reduces Mu Opioid Receptor Expression in the Intercalated Nuclei of the Rat Amygdala. Cell Mol Neurobiol 2021; 41:1119-1129. [PMID: 33400082 DOI: 10.1007/s10571-020-01026-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
The amygdala plays an important role in the integration of responses to noxious and fearful stimuli. Sensory information from many systems is integrated in the lateral and basolateral amygdala and transmitted to the central amygdala, the major output nucleus of the amygdala regulating both motor and emotional responses. The network of intercalated cells (ITC) which surrounds the lateral and basolateral amygdala and serves to modulate information flow from the lateral amygdala to the central nucleus, express a very high local concentration of mu-type opioid receptors. Loss of the ITC neurons impairs fear extinction. We demonstrate here that exposure of rats to a severe stress experience resulted in a marked downregulation of the level of expression of mu opioid receptors in the ITC nuclei over a period of at least 24 h after the end of the stress exposure. The endogenous opioid dynorphin is also expressed in the central and ITC nuclei of the amygdala. Following stress exposure, we also observed an increase in the expression in the more lateral regions of the central amygdala of pro-dynorphin mRNA and a peptide product of pro-dynorphin with known affinity for mu opioid receptors. It is possible that the downregulation of mu receptors in ITC neurons after stress may result from sustained activation and internalization of mu receptors following a stress-induced increase in the release of endogenous opioid peptides.
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2
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Abstract
Opioids, such as morphine and fentanyl, are widely used for the treatment of severe pain; however, prolonged treatment with these drugs leads to the development of tolerance and can lead to opioid use disorder. The "Opioid Epidemic" has generated a drive for a deeper understanding of the fundamental signaling mechanisms of opioid receptors. It is generally thought that the three types of opioid receptors (μ, δ, κ) are activated by endogenous peptides derived from three different precursors: Proopiomelanocortin, proenkephalin, and prodynorphin. Posttranslational processing of these precursors generates >20 peptides with opioid receptor activity, leading to a long-standing question of the significance of this repertoire of peptides. Here, we address some aspects of this question using a technical tour de force approach to systematically evaluate ligand binding and signaling properties ([35S]GTPγS binding and β-arrestin recruitment) of 22 peptides at each of the three opioid receptors. We show that nearly all tested peptides are able to activate the three opioid receptors, and many of them exhibit agonist-directed receptor signaling (functional selectivity). Our data also challenge the dogma that shorter forms of β-endorphin do not exhibit receptor activity; we show that they exhibit robust signaling in cultured cells and in an acute brain slice preparation. Collectively, this information lays the groundwork for improved understanding of the endogenous opioid system that will help in developing more effective treatments for pain and addiction.
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Mercatelli D, Bezard E, Eleopra R, Zaveri NT, Morari M. Managing Parkinson's disease: moving ON with NOP. Br J Pharmacol 2020; 177:28-47. [PMID: 31648371 PMCID: PMC6976791 DOI: 10.1111/bph.14893] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/12/2019] [Accepted: 09/25/2019] [Indexed: 01/08/2023] Open
Abstract
The opioid-like neuropeptide nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP receptor) contribute to Parkinson's disease (PD) and motor complications associated with levodopa therapy. The N/OFQ-NOP receptor system is expressed in cortical and subcortical motor areas and, notably, in dopaminergic neurons of the substantia nigra compacta. Dopamine depletion, as in rodent models of PD results in up-regulation of N/OFQ transmission in the substantia nigra and down-regulation of N/OFQ transmission in the striatum. Consistent with this, NOP receptor antagonists relieve motor deficits in PD models by reinstating the physiological balance between excitatory and inhibitory inputs impinging on nigro-thalamic GABAergic neurons. NOP receptor antagonists also counteract the degeneration of nigrostriatal dopaminergic neurons, possibly by attenuating the excitotoxicity or modulating the immune response. Conversely, NOP receptor agonists attenuate levodopa-induced dyskinesia by attenuating the hyperactivation of striatal D1 receptor signalling in neurons of the direct striatonigral pathway. The N/OFQ-NOP receptor system might represent a novel target in the therapy of PD.
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Affiliation(s)
- Daniela Mercatelli
- Department of Medical Sciences, Section of PharmacologyUniversity of Ferrara and National Institute of NeuroscienceFerraraItaly
| | - Erwan Bezard
- Institut des Maladies Neurodégénératives, UMR 5293Université de BordeauxBordeauxFrance
- Institut des Maladies Neurodégénératives, Centre National de la Recherche Scientifique, UMR 5293BordeauxFrance
| | - Roberto Eleopra
- Neurology Unit 1Fondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Nurulain T. Zaveri
- Astraea Therapeutics, Medicinal Chemistry DivisionMountain ViewCaliforniaUSA
| | - Michele Morari
- Department of Medical Sciences, Section of PharmacologyUniversity of Ferrara and National Institute of NeuroscienceFerraraItaly
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Mercatelli D, Pisanò CA, Novello S, Morari M. NOP Receptor Ligands and Parkinson's Disease. Handb Exp Pharmacol 2019; 254:213-232. [PMID: 30689087 DOI: 10.1007/164_2018_199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nociceptin/Orphanin FQ (N/OFQ) and its NOP receptor are highly expressed in motor areas of the rodent, nonhuman, and human primate brain, such as primary motor cortex, thalamus, globus pallidus, striatum, and substantia nigra. Endogenous N/OFQ negatively regulates motor behavior and dopamine transmission through NOP receptors expressed by dopaminergic neurons of the substantia nigra compacta. Consistent with the existence of an N/OFQ tone over dopaminergic transmission, blockade of NOP receptor antagonists increases striatal dopamine release. In this chapter, we will review the evidence linking the N/OFQ-NOP receptor system to Parkinson's disease (PD). We will first discuss data showing that the central N/OFQ-NOP receptor system undergoes plastic changes in different basal ganglia nuclei following dopamine depletion. Then we will show that NOP receptor antagonists relieve motor deficits in different rodent and nonhuman primate models of PD. Mechanistically, NOP receptor blockade in substantia nigra reticulata results in rebalancing of the inhibitory GABAergic and excitatory glutamatergic inputs impinging on nigro-thalamic GABAergic neurons, leading to thalamic disinhibition. We will also present data showing that, in addition to motor symptoms, N/OFQ also plays a role in the parkinsonian neurodegeneration. In fact, NOP receptor antagonists possess neuroprotective/neurorescue properties in in vitro and in vivo models of PD.
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Affiliation(s)
- Daniela Mercatelli
- Department of Medical Sciences, Section of Pharmacology, and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy
| | - Clarissa Anna Pisanò
- Department of Medical Sciences, Section of Pharmacology, and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy
| | - Salvatore Novello
- Department of Medical Sciences, Section of Pharmacology, and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy
| | - Michele Morari
- Department of Medical Sciences, Section of Pharmacology, and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy.
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5
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Caputi FF, Romualdi P, Candeletti S. Regulation of the Genes Encoding the ppN/OFQ and NOP Receptor. Handb Exp Pharmacol 2019; 254:141-162. [PMID: 30689088 DOI: 10.1007/164_2018_196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Over the years, the ability of N/OFQ-NOP receptor system in modulating several physiological functions, including the release of neurotransmitters, anxiety-like behavior responses, modulation of the reward circuitry, inflammatory signaling, nociception, and motor function, has been examined in several brain regions and at spinal level. This chapter collects information related to the genes encoding the ppN/OFQ and NOP receptor, their regulation, and relative transcriptional control mechanisms. Furthermore, genetic manipulations, polymorphisms, and epigenetic alterations associated with different pathological conditions are discussed. The evidence here collected indicates that the study of ppN/OFQ and NOP receptor gene expression may offer novel opportunities in the field of personalized therapies and highlights this system as a good "druggable target" for different pathological conditions.
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Affiliation(s)
- Francesca Felicia Caputi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Bologna, Italy.
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
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Khan MS, Boileau I, Kolla N, Mizrahi R. A systematic review of the role of the nociceptin receptor system in stress, cognition, and reward: relevance to schizophrenia. Transl Psychiatry 2018; 8:38. [PMID: 29391391 PMCID: PMC5804030 DOI: 10.1038/s41398-017-0080-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 10/13/2017] [Accepted: 11/13/2017] [Indexed: 01/08/2023] Open
Abstract
Schizophrenia is a debilitating neuropsychiatric illness that is characterized by positive, negative, and cognitive symptoms. Research over the past two decades suggests that the nociceptin receptor system may be involved in domains affected in schizophrenia, based on evidence aligning it with hallmark features of the disorder. First, aberrant glutamatergic and striatal dopaminergic function are associated with psychotic symptoms, and the nociceptin receptor system has been shown to regulate dopamine and glutamate transmission. Second, stress is a critical risk factor for first break and relapse in schizophrenia, and evidence suggests that the nociceptin receptor system is also directly involved in stress modulation. Third, cognitive deficits are prevalent in schizophrenia, and the nociceptin receptor system has significant impact on learning and working memory. Last, reward processing is disrupted in schizophrenia, and nociceptin signaling has been shown to regulate reward cue salience. These findings provide the foundation for the involvement of the nociceptin receptor system in the pathophysiology of schizophrenia and outline the need for future research into this system.
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Affiliation(s)
- Muhammad Saad Khan
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Isabelle Boileau
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada
| | - Nathan Kolla
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College St., Toronto, ON, M5T 1R8, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada.
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St., Toronto, ON, M5T 1R8, Canada.
- Department of Psychiatry, University of Toronto, 250 College St., Toronto, ON, M5T 1R8, Canada.
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Collins LM, Dal Bo G, Calcagno M, Monzón-Sandoval J, Sullivan AM, Gutierrez H, Morari M, O'Keeffe GW. Nociceptin/Orphanin FQ Inhibits the Survival and Axon Growth of Midbrain Dopaminergic Neurons Through a p38-MAPK Dependent Mechanism. Mol Neurobiol 2016; 53:7284-7297. [PMID: 26687234 DOI: 10.1007/s12035-015-9611-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/03/2015] [Indexed: 12/24/2022]
Abstract
Nociceptin/orphanin FQ (N/OFQ) is an opioid-like neuropeptide that binds and signals through a G-protein-coupled receptor called the N/OFQ peptide (NOP) receptor. N/OFQ and the NOP receptor are expressed in the midbrain and have been implicated in the pathogenesis of Parkinson's disease (PD). Genetic removal of the N/OFQ precursor partially protects midbrain dopaminergic neurons from 1-methyl-4-phenylpyridine-induced toxicity, suggesting that endogenous N/OFQ may be detrimental to dopaminergic neurons. However, whether N/OFQ directly affects the survival and growth of dopaminergic neurons is unknown. Here, we show that N/OFQ has a detrimental effect on the survival of dopaminergic neurons and the growth of their axons in primary cultures of the E14 rat ventral mesencephalon. N/OFQ potentiates the effects of the neurotoxins 6-hydroxydopamine and 1-methyl-4-phenylpyridinium through p38-MAPK signalling. We also show that like α-synuclein, there is a significant reduction in N/OFQ messenger RNA (mRNA) expression in the midbrain of patients with Parkinson's disease. These results demonstrate for the first time that N/OFQ is detrimental to the survival and growth of dopaminergic neurons and that its expression is altered in the midbrain of patients with Parkinson's disease.
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Affiliation(s)
- Louise M Collins
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Giorgia Dal Bo
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| | - Mariangela Calcagno
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44121, Ferrara, Italy
| | - Jimena Monzón-Sandoval
- School of Life Sciences, University of Lincoln, Lincoln, Lincolnshire, LN6 7TS, UK
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Aideen M Sullivan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Humberto Gutierrez
- School of Life Sciences, University of Lincoln, Lincoln, Lincolnshire, LN6 7TS, UK
| | - Michele Morari
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44121, Ferrara, Italy.
| | - Gerard W O'Keeffe
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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8
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Toll L, Bruchas MR, Calo' G, Cox BM, Zaveri NT. Nociceptin/Orphanin FQ Receptor Structure, Signaling, Ligands, Functions, and Interactions with Opioid Systems. Pharmacol Rev 2016; 68:419-57. [PMID: 26956246 PMCID: PMC4813427 DOI: 10.1124/pr.114.009209] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The NOP receptor (nociceptin/orphanin FQ opioid peptide receptor) is the most recently discovered member of the opioid receptor family and, together with its endogenous ligand, N/OFQ, make up the fourth members of the opioid receptor and opioid peptide family. Because of its more recent discovery, an understanding of the cellular and behavioral actions induced by NOP receptor activation are less well developed than for the other members of the opioid receptor family. All of these factors are important because NOP receptor activation has a clear modulatory role on mu opioid receptor-mediated actions and thereby affects opioid analgesia, tolerance development, and reward. In addition to opioid modulatory actions, NOP receptor activation has important effects on motor function and other physiologic processes. This review discusses how NOP pharmacology intersects, contrasts, and interacts with the mu opioid receptor in terms of tertiary structure and mechanism of receptor activation; location of receptors in the central nervous system; mechanisms of desensitization and downregulation; cellular actions; intracellular signal transduction pathways; and behavioral actions with respect to analgesia, tolerance, dependence, and reward. This is followed by a discussion of the agonists and antagonists that have most contributed to our current knowledge. Because NOP receptors are highly expressed in brain and spinal cord and NOP receptor activation sometimes synergizes with mu receptor-mediated actions and sometimes opposes them, an understanding of NOP receptor pharmacology in the context of these interactions with the opioid receptors will be crucial to the development of novel therapeutics that engage the NOP receptor.
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Affiliation(s)
- Lawrence Toll
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Michael R Bruchas
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Girolamo Calo'
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Brian M Cox
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Nurulain T Zaveri
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
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9
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Arcuri L, Viaro R, Bido S, Longo F, Calcagno M, Fernagut PO, Zaveri NT, Calò G, Bezard E, Morari M. Genetic and pharmacological evidence that endogenous nociceptin/orphanin FQ contributes to dopamine cell loss in Parkinson's disease. Neurobiol Dis 2016; 89:55-64. [PMID: 26804029 DOI: 10.1016/j.nbd.2016.01.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/09/2016] [Accepted: 01/19/2016] [Indexed: 12/30/2022] Open
Abstract
To investigate whether the endogenous neuropeptide nociceptin/orphanin FQ (N/OFQ) contributes to the death of dopamine neurons in Parkinson's disease, we undertook a genetic and a pharmacological approach using NOP receptor knockout (NOP(-/-)) mice, and the selective and potent small molecule NOP receptor antagonist (-)-cis-1-methyl-7-[[4-(2,6-dichlorophenyl)piperidin-1-yl]methyl]-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ol (SB-612111). Stereological unbiased methods were used to estimate the total number of dopamine neurons in the substantia nigra of i) NOP(-/-) mice acutely treated with the parkinsonian neurotoxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP), ii) naïve mice subacutely treated with MPTP, alone or in combination with SB-612111, iii) rats injected with a recombinant adeno-associated viral (AAV) vector overexpressing human mutant p.A53T α-synuclein, treated with vehicle or SB-612111. NOP(-/-) mice showed a 50% greater amount of nigral dopamine neurons spared in response to acute MPTP compared to controls, which was associated with a milder motor impairment. SB-612111, given 4 days after MPTP treatment to mimic the clinical condition, prevented the loss of nigral dopamine neurons and striatal dopaminergic terminals caused by subacute MPTP. SB-612111, administered a week after the AAV injections in a clinically-driven protocol, also increased by 50% both the number of spared nigral dopamine neurons and striatal dopamine terminals, and prevented accompanying motor deficits induced by α-synuclein. We conclude that endogenous N/OFQ contributes to dopamine neuron loss in pathogenic and etiologic models of Parkinson's disease through NOP receptor-mediated mechanisms. NOP receptor antagonists might prove effective as disease-modifying agents in Parkinson's disease, through the rescue of degenerating nigral dopamine neurons and/or the protection of the healthy ones.
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Affiliation(s)
- Ludovico Arcuri
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Riccardo Viaro
- Department of Biomedical and Specialty Surgical Sciences, Section of Human Physiology, University of Ferrara, via Fossato di Mortara 19, 44121 Ferrara, Italy
| | - Simone Bido
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Francesco Longo
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Mariangela Calcagno
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Pierre-Olivier Fernagut
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Nurulain T Zaveri
- Astraea Therapeutics, 320 Logue Avenue, Mountain View, CA 94040, USA
| | - Girolamo Calò
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy
| | - Erwan Bezard
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France
| | - Michele Morari
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy; Neuroscience Center and National Institute of Neuroscience, University of Ferrara, via Fossato di Mortara 17-19, 44121 Ferrara, Italy.
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10
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Bastide MF, Meissner WG, Picconi B, Fasano S, Fernagut PO, Feyder M, Francardo V, Alcacer C, Ding Y, Brambilla R, Fisone G, Jon Stoessl A, Bourdenx M, Engeln M, Navailles S, De Deurwaerdère P, Ko WKD, Simola N, Morelli M, Groc L, Rodriguez MC, Gurevich EV, Quik M, Morari M, Mellone M, Gardoni F, Tronci E, Guehl D, Tison F, Crossman AR, Kang UJ, Steece-Collier K, Fox S, Carta M, Angela Cenci M, Bézard E. Pathophysiology of L-dopa-induced motor and non-motor complications in Parkinson's disease. Prog Neurobiol 2015. [PMID: 26209473 DOI: 10.1016/j.pneurobio.2015.07.002] [Citation(s) in RCA: 347] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Involuntary movements, or dyskinesia, represent a debilitating complication of levodopa (L-dopa) therapy for Parkinson's disease (PD). L-dopa-induced dyskinesia (LID) are ultimately experienced by the vast majority of patients. In addition, psychiatric conditions often manifested as compulsive behaviours, are emerging as a serious problem in the management of L-dopa therapy. The present review attempts to provide an overview of our current understanding of dyskinesia and other L-dopa-induced dysfunctions, a field that dramatically evolved in the past twenty years. In view of the extensive literature on LID, there appeared a critical need to re-frame the concepts, to highlight the most suitable models, to review the central nervous system (CNS) circuitry that may be involved, and to propose a pathophysiological framework was timely and necessary. An updated review to clarify our understanding of LID and other L-dopa-related side effects was therefore timely and necessary. This review should help in the development of novel therapeutic strategies aimed at preventing the generation of dyskinetic symptoms.
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Affiliation(s)
- Matthieu F Bastide
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Wassilios G Meissner
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; Department of Neurology, University Hospital Bordeaux, France
| | - Barbara Picconi
- Laboratory of Neurophysiology, Fondazione Santa Lucia, IRCCS, Rome, Italy
| | - Stefania Fasano
- Division of Neuroscience, Institute of Experimental Neurology, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Pierre-Olivier Fernagut
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Michael Feyder
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Veronica Francardo
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Cristina Alcacer
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Yunmin Ding
- Department of Neurology, Columbia University, New York, USA
| | - Riccardo Brambilla
- Division of Neuroscience, Institute of Experimental Neurology, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Gilberto Fisone
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - A Jon Stoessl
- Pacific Parkinson's Research Centre and National Parkinson Foundation Centre of Excellence, University of British Columbia, Vancouver, Canada
| | - Mathieu Bourdenx
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Michel Engeln
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Sylvia Navailles
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Philippe De Deurwaerdère
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Wai Kin D Ko
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - Nicola Simola
- Department of Biomedical Sciences, Section of Neuropsychopharmacology, Cagliari University, 09124 Cagliari, Italy
| | - Micaela Morelli
- Department of Biomedical Sciences, Section of Neuropsychopharmacology, Cagliari University, 09124 Cagliari, Italy
| | - Laurent Groc
- Univ. de Bordeaux, Institut Interdisciplinaire de neurosciences, UMR 5297, 33000 Bordeaux, France; CNRS, Institut Interdisciplinaire de neurosciences, UMR 5297, 33000 Bordeaux, France
| | - Maria-Cruz Rodriguez
- Department of Neurology, Hospital Universitario Donostia and Neuroscience Unit, Bio Donostia Research Institute, San Sebastian, Spain
| | - Eugenia V Gurevich
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Maryka Quik
- Center for Health Sciences, SRI International, CA 94025, USA
| | - Michele Morari
- Department of Medical Sciences, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Manuela Mellone
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milano, Italy
| | - Fabrizio Gardoni
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milano, Italy
| | - Elisabetta Tronci
- Department of Biomedical Sciences, Physiology Section, Cagliari University, Cagliari, Italy
| | - Dominique Guehl
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France
| | - François Tison
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; Department of Neurology, University Hospital Bordeaux, France
| | | | - Un Jung Kang
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Kathy Steece-Collier
- Michigan State University, College of Human Medicine, Department of Translational Science and Molecular Medicine & The Udall Center of Excellence in Parkinson's Disease Research, 333 Bostwick Ave NE, Grand Rapids, MI 49503, USA
| | - Susan Fox
- Morton & Gloria Shulman Movement Disorders Center, Toronto Western Hospital, Toronto, Ontario M4T 2S8, Canada
| | - Manolo Carta
- Department of Biomedical Sciences, Physiology Section, Cagliari University, Cagliari, Italy
| | - M Angela Cenci
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Erwan Bézard
- Univ. de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 33000 Bordeaux, France; Motac Neuroscience Ltd, Manchester, UK.
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11
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Marti M, Mela F, Budri M, Volta M, Malfacini D, Molinari S, Zaveri NT, Ronzoni S, Petrillo P, Calò G, Morari M. Acute and chronic antiparkinsonian effects of the novel nociceptin/orphanin FQ receptor antagonist NiK-21273 in comparison with SB-612111. Br J Pharmacol 2013; 168:863-79. [PMID: 22994368 DOI: 10.1111/j.1476-5381.2012.02219.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/25/2012] [Accepted: 08/30/2012] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor antagonists have been proposed as a novel therapeutic approach to Parkinson's disease. Main limitations of previous studies were the use of structurally similar compounds and the evaluation of their acute effects only. We report here on the acute and long-term antiparkinsonian effects of the novel compound 2-[3-[4-(2-chloro-6-fluoro-phenyl)-piperidin-1-ylmethyl]-2-(morpholine-4-carbonyl)-indol-1-yl]-acetamide (NiK-21273) in comparison with the potent and selective NOP receptor antagonist SB-612111. EXPERIMENTAL APPROACH Basic pharmacological properties of NiK-21273 were studied in cell lines and isolated tissues (mouse and rat vas deferens). Antiparkinsonian effects were studied in reserpinized mice and 6-hydroxydopamine hemilesioned rats under both acute and chronic administration protocols. KEY RESULTS In vitro, NiK-21273 behaved as a potent (pA(2) 7.7) and selective NOP receptor antagonist. In vivo, it reduced hypokinesia in reserpinized mice at 0.1 and 1 but not 10 mg·kg(-1), whereas SB-612111 (0.01-1 mg·kg(-1)) provided a dose-dependent antiparkinsonian effect. NiK-21273 ameliorated motor performance in 6-hydroxydopamine hemilesioned rats at 0.5 and 5 but not 15 mg·kg(-1). SB-612111 replicated these effects in the 0.01-1 mg·kg(-1) range without loss of efficacy. Both antagonists synergized with L-DOPA at subthreshold doses. Chronic administration of NiK-21273 provided delayed improvement in baseline activity at 0.5 and 1.5 mg·kg(-1), although tolerance to the higher dose was observed. Conversely, SB-612111 (1 mg·kg(-1)) maintained its effects over time without modifying baseline activity. CONCLUSIONS AND IMPLICATIONS NOP receptor antagonists provide motor benefit in parkinsonism models although the 'therapeutic' window and long-term effects may vary between compounds.
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Affiliation(s)
- M Marti
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, Ferrara, Italy
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12
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Chan MH, Kleinschmidt-DeMasters BK, Donson AM, Birks DK, Foreman NK, Rush SZ. Pediatric brainstem gangliogliomas show overexpression of neuropeptide prepronociceptin (PNOC) by microarray and immunohistochemistry. Pediatr Blood Cancer 2012; 59:1173-9. [PMID: 22706982 PMCID: PMC4681521 DOI: 10.1002/pbc.24232] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/22/2012] [Indexed: 11/07/2022]
Abstract
BACKGROUND Gangliogliomas (GGs) primary to brainstem are rare, with the overwhelming majority of GGs occurring in supratentorial, especially temporal lobe, locations. A less favorable prognosis exists for brainstem GGs, despite their usually identical WHO grade I status. Few large clinical series, and limited biological information, exists on these tumors, especially gene expression. PROCEDURE Seven pediatric brainstem GGs, all with classic histological features, seen at our institution since 2000 were identified. Frozen section material was available for gene expression microarray profiling from five of seven brainstem GGs and compared with that from three non-brainstem pediatric GGs. RESULTS Significant upregulation of a number of genes was identified, most of which were involved in pathways of neural signaling, embryonic development, and pattern specification in pediatric brainstem GGs compared to non-brainstem. The single largest upregulated gene was a 256-fold increase in the expression of the neuropeptide prepronociceptin (PNOC); the protein product of this gene has been implicated in neuronal growth. Overexpression was validated by Western blot and by immunohistochemistry (IHC). Strong IHC expression of PNOC was seen in neoplastic neurons of 7/7 brainstem GGs, but was significantly weaker in non-brainstem GGs, and completely negative in normal pediatric autopsy brainstem controls. CONCLUSIONS PNOC IHC was often superior to IHC for NeuN, synaptophysin, or neurofilament for highlighting neoplastic neurons.
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Affiliation(s)
- Mike H. Chan
- Department of Neuro-oncology, Children’s Hospital Colorado, Aurora, Colorado, 13123 East 16th Avenue, Aurora, CO 80045
| | - B. K. Kleinschmidt-DeMasters
- Department of Pathology, Anschutz Medical Campus, University of Colorado at Denver, 12800 East 19 Avenue, Aurora, CO 80045, USA,Department of Neurology, Anschutz Medical Campus, University of Colorado at Denver, 12800 East 19 Avenue, Aurora, CO 80045, USA,Department of Neurosurgery, Anschutz Medical Campus, University of Colorado at Denver, 12800 East 19 Avenue, Aurora, CO 80045, USA
| | - Andrew M. Donson
- Department of Neuro-oncology, Children’s Hospital Colorado, Aurora, Colorado, 13123 East 16th Avenue, Aurora, CO 80045
| | - Diane K. Birks
- Department of Neurosurgery, Anschutz Medical Campus, University of Colorado at Denver, 12800 East 19 Avenue, Aurora, CO 80045, USA
| | - Nicholas K. Foreman
- Department of Neuro-oncology, Children’s Hospital Colorado, Aurora, Colorado, 13123 East 16th Avenue, Aurora, CO 80045
| | - Sarah Z. Rush
- Department of Neuro-oncology, Children’s Hospital Colorado, Aurora, Colorado, 13123 East 16th Avenue, Aurora, CO 80045
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13
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Marti M, Rodi D, Li Q, Guerrini R, Fasano S, Morella I, Tozzi A, Brambilla R, Calabresi P, Simonato M, Bezard E, Morari M. Nociceptin/orphanin FQ receptor agonists attenuate L-DOPA-induced dyskinesias. J Neurosci 2012; 32:16106-19. [PMID: 23152595 PMCID: PMC6794016 DOI: 10.1523/jneurosci.6408-11.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 09/11/2012] [Accepted: 09/14/2012] [Indexed: 11/21/2022] Open
Abstract
In the present study we investigated whether the neuropeptide nociceptin/orphanin FQ (N/OFQ), previously implicated in the pathogenesis of Parkinson's disease, also affects L-DOPA-induced dyskinesia. In striatal slices of naive rodents, N/OFQ (0.1-1 μm) prevented the increase of ERK phosphorylation and the loss of depotentiation of synaptic plasticity induced by the D1 receptor agonist SKF38393 in spiny neurons. In vivo, exogenous N/OFQ (0.03-1 nmol, i.c.v.) or a synthetic N/OFQ receptor agonist given systemically (0.01-1 mg/Kg) attenuated dyskinesias expression in 6-hydroxydopamine hemilesioned rats primed with L-DOPA, without causing primary hypolocomotive effects. Conversely, N/OFQ receptor antagonists worsened dyskinesia expression. In vivo microdialysis revealed that N/OFQ prevented dyskinesias simultaneously with its neurochemical correlates such as the surge of nigral GABA and glutamate, and the reduction of thalamic GABA. Regional microinjections revealed that N/OFQ attenuated dyskinesias more potently and effectively when microinjected in striatum than substantia nigra (SN) reticulata, whereas N/OFQ receptor antagonists were ineffective in striatum but worsened dyskinesias when given in SN. Quantitative autoradiography showed an increase in N/OFQ receptor binding in striatum and a reduction in SN of both unprimed and dyskinetic 6-hydroxydopamine rats, consistent with opposite adaptive changes of N/OFQ transmission. Finally, the N/OFQ receptor synthetic agonist also reduced dyskinesia expression in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated dyskinetic macaques without affecting the global parkinsonian score. We conclude that N/OFQ receptor agonists may represent a novel strategy to counteract L-DOPA-induced dyskinesias. Their action is possibly mediated by upregulated striatal N/OFQ receptors opposing the D1 receptor-mediated overactivation of the striatonigral direct pathway.
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Affiliation(s)
- Matteo Marti
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara and National Institute of Neuroscience, 44100 Ferrara Italy
| | - Donata Rodi
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara and National Institute of Neuroscience, 44100 Ferrara Italy
| | - Qin Li
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, 100864 Beijing, China
| | - Remo Guerrini
- Department of Pharmaceutical Sciences, University of Ferrara, Ferrara, 44100 Italy
| | - Stefania Fasano
- Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute and University, 20123 Milano, Italy
| | - Ilaria Morella
- Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute and University, 20123 Milano, Italy
| | - Alessandro Tozzi
- Clinica Neurologica, Dip. Specialità Medico-Chirurgiche e Sanità Pubblica, Università di Perugia, Ospedale Santa Maria della Misericordia, 06123 Perugia, Italy
- Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, 00179 Rome, Italy
| | - Riccardo Brambilla
- Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute and University, 20123 Milano, Italy
| | - Paolo Calabresi
- Clinica Neurologica, Dip. Specialità Medico-Chirurgiche e Sanità Pubblica, Università di Perugia, Ospedale Santa Maria della Misericordia, 06123 Perugia, Italy
- Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, 00179 Rome, Italy
| | - Michele Simonato
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara and National Institute of Neuroscience, 44100 Ferrara Italy
| | - Erwan Bezard
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, 100864 Beijing, China
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, F-33000 France; and
- Centre National de la Recherche Scientifique, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, F-33000 France
| | - Michele Morari
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara and National Institute of Neuroscience, 44100 Ferrara Italy
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Abstract
This paper is the thirty-third consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2010 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, USA.
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15
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Current world literature. Curr Opin Neurol 2011; 24:511-6. [PMID: 21900773 DOI: 10.1097/wco.0b013e32834be5c1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Volta M, Viaro R, Trapella C, Marti M, Morari M. Dopamine-nociceptin/orphanin FQ interactions in the substantia nigra reticulata of hemiparkinsonian rats: involvement of D2/D3 receptors and impact on nigro-thalamic neurons and motor activity. Exp Neurol 2011; 228:126-37. [PMID: 21215744 DOI: 10.1016/j.expneurol.2010.12.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 12/15/2010] [Accepted: 12/29/2010] [Indexed: 11/22/2022]
Abstract
Nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor antagonists proved to be effective in alleviating experimental parkinsonism. Nonetheless, loss of effectiveness or even worsening of parkinsonian symptoms have been observed at high doses. With the aim of clarifying the circuitry underlying the dual action of NOP receptor antagonists and the role of endogenous dopamine, the NOP receptor antagonist 1-benzyl-N-[3-[spiroisobenzofuran-1(3H),4'-piperidin-1-yl]propyl]pyrrolidine-2-carboxamide (Compound 24) and the D(2)/D(3) receptor antagonist raclopride were used in 6-hydroxydopamine hemilesioned rats. Systemically administered Compound 24 improved motor activity in the 0.1-10mg/kg dose range being ineffective at 30 mg/kg. To confirm NOP selectivity, Compound 24 improved motor performance in wild-type mice at 1 and 10mg/kg and inhibited it at 60 mg/kg, being ineffective in NOP receptor knockout mice. To prove that the bell-shaped profile was mediated by nigral NOP receptors, reverse dialysis of Compound 24 (0.03 μM) in substantia nigra reticulata ameliorated akinesia whereas Compound 24 (3 μM) was ineffective. To demonstrate that motor responses were mediated by tuning inhibitory and excitatory inputs to nigro-thalamic neurons, the low concentration elevated GABA and reduced glutamate in substantia nigra, simultaneously reducing GABA levels in ventro-medial thalamus. Conversely, the higher concentration reduced nigral and elevated thalamic GABA, without affecting nigral glutamate levels. Co-perfusion with raclopride (1 μM) abolished the antiakinetic action of Compound 24 (0.03 μM) and turned the ineffectiveness of Compound 24 (3 μM) into an antiakinetic effect. The low concentration reduced nigral but did not affect thalamic GABA whereas the higher concentration elevated nigral and reduced thalamic GABA. Neither concentration affected nigral glutamate. We conclude that dual motor effects of Compound 24 in hemiparkinsonian rats are accomplished through blockade of nigral NOP receptors resulting in opposite modulation of nigro-thalamic neurons. Endogenous dopamine contributes to these responses affecting the level of GABAergic inhibition of the nigral output via D(2)/D(3) receptors.
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Affiliation(s)
- Mattia Volta
- Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, Ferrara, Italy
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