1
|
Lu Y, Hatzipantelis CJ, Langmead CJ, Stewart GD. Molecular insights into orphan G protein-coupled receptors relevant to schizophrenia. Br J Pharmacol 2024; 181:2095-2113. [PMID: 37605621 DOI: 10.1111/bph.16221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/25/2023] [Accepted: 07/23/2023] [Indexed: 08/23/2023] Open
Abstract
Schizophrenia remains a sizable socio-economic burden that continues to be treated with therapeutics based on 70-year old science. All currently approved therapeutics primarily target the dopamine D2 receptor to achieve their efficacy. Whilst dopaminergic dysregulation is a key feature in this disorder, the targeting of dopaminergic machinery has yielded limited efficacy and an appreciable side effect burden. Over the recent decades, numerous drugs that engage non-dopaminergic G protein-coupled receptors (GPCRs) have yielded a promise of efficacy without the deleterious side effect profile, yet none have successfully completed clinical studies and progressed to the market. More recently, there has been increased attention around non-dopaminergic GPCR-targeting drugs, which demonstrated efficacy in some schizophrenia symptom domains. This provides renewed hope that effective schizophrenia treatment may lie outside of the dopaminergic space. Despite the potential for muscarinic receptor- (and other well-characterised GPCR families) targeting drugs to treat schizophrenia, they are often plagued with complications such as lack of receptor subtype selectivity and peripheral on-target side effects. Orphan GPCR studies have opened a new avenue of exploration with many demonstrating schizophrenia-relevant mechanisms and a favourable expression profile, thus offering potential for novel drug development. This review discusses centrally expressed orphan GPCRs: GPR3, GPR6, GPR12, GPR52, GPR85, GPR88 and GPR139 and their relationship to schizophrenia. We review their expression, signalling mechanisms and cellular function, in conjunction with small molecule development and structural insights. We seek to provide a snapshot of the growing evidence and development potential of new classes of schizophrenia therapeutics. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
Collapse
Affiliation(s)
- Yao Lu
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | | | - Christopher J Langmead
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Australia
- Phrenix Therapeutics, Parkville, Australia
| | - Gregory D Stewart
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Australia
- Phrenix Therapeutics, Parkville, Australia
| |
Collapse
|
2
|
Anversa RG, Maddern XJ, Lawrence AJ, Walker LC. Orphan peptide and G protein-coupled receptor signalling in alcohol use disorder. Br J Pharmacol 2024; 181:595-609. [PMID: 38073127 PMCID: PMC10953447 DOI: 10.1111/bph.16301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024] Open
Abstract
Neuropeptides and G protein-coupled receptors (GPCRs) have long been, and continue to be, one of the most popular target classes for drug discovery in CNS disorders, including alcohol use disorder (AUD). Yet, orphaned neuropeptide systems and receptors (oGPCR), which have no known cognate receptor or ligand, remain understudied in drug discovery and development. Orphan neuropeptides and oGPCRs are abundantly expressed within the brain and represent an unprecedented opportunity to address brain function and may hold potential as novel treatments for disease. Here, we describe the current literature regarding orphaned neuropeptides and oGPCRs implicated in AUD. Specifically, in this review, we focus on the orphaned neuropeptide cocaine- and amphetamine-regulated transcript (CART), and several oGPCRs that have been directly implicated in AUD (GPR6, GPR26, GPR88, GPR139, GPR158) and discuss their potential and pitfalls as novel treatments, and progress in identifying their cognate receptors or ligands.
Collapse
Affiliation(s)
- Roberta Goncalves Anversa
- Florey Institute of Neuroscience and Mental HealthMelbourneVICAustralia
- Florey Department of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
| | - Xavier J. Maddern
- Florey Institute of Neuroscience and Mental HealthMelbourneVICAustralia
- Florey Department of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
| | - Andrew J. Lawrence
- Florey Institute of Neuroscience and Mental HealthMelbourneVICAustralia
- Florey Department of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
| | - Leigh C. Walker
- Florey Institute of Neuroscience and Mental HealthMelbourneVICAustralia
- Florey Department of Neuroscience and Mental HealthUniversity of MelbourneMelbourneVICAustralia
| |
Collapse
|
3
|
Ben Hamida S, Carter M, Darcq E, Sourty M, Rahman MT, Decker AM, Jin C, Kieffer BL. The GPR88 agonist RTI-13951-33 reduces alcohol drinking and seeking in mice. Addict Biol 2022; 27:e13227. [PMID: 36301207 PMCID: PMC9539967 DOI: 10.1111/adb.13227] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/26/2023]
Abstract
GPR88 is an orphan G-protein-coupled receptor that is considered a potential target to treat neuropsychiatric disorders, including addiction. Most knowledge about GPR88 function stems from knockout mouse studies, and in vivo pharmacology is still scarce. Here we examine the effects of the novel brain-penetrant agonist RTI-13951-33 on several alcohol-related behaviours in the mouse. In the intermittent-access-two-bottle-choice paradigm, the compound reduced excessive voluntary alcohol drinking, while water drinking was intact. This was observed for C57BL/6 mice, as well as for control but not Gpr88 knockout mice, demonstrating efficacy and specificity of the drug in vivo. In the drinking-in-the-dark paradigm, RTI-13951-33 also reduced binge-like drinking behaviour for control but not Gpr88 knockout mice, confirming the alcohol consumption-reducing effect and in vivo specificity of the drug. When C57BL/6 mice were trained for alcohol self-administration, RTI-13951-33 decreased the number of nose-pokes over a 4-h session and reduced the number of licks and bursts of licks, suggesting reduced motivation to obtain alcohol. Finally, RTI-13951-33 did not induce any place preference or aversion but reduced the expression of conditioned place preference to alcohol, indicative of a reduction of alcohol-reward seeking. Altogether, data show that RTI-13951-33 limits alcohol intake under distinct conditions that require consummatory behaviour, operant response or association with contextual cues. RTI-13951-33 therefore is a promising lead compound to evaluate GPR88 as a therapeutic target for alcohol use disorders. More broadly, RTI-13951-33 represents a unique tool to better understand GPR88 function, disentangle receptor roles in development from those in the adult and perhaps address other neuropsychiatric disorders.
Collapse
Affiliation(s)
- Sami Ben Hamida
- Douglas Mental Health University InstituteMontrealQuebecCanada,INSERM UMR 1247University of Picardie Jules VerneAmiensFrance
| | - Michelle Carter
- Douglas Mental Health University InstituteMontrealQuebecCanada
| | - Emmanuel Darcq
- Douglas Mental Health University InstituteMontrealQuebecCanada,Department of PsychiatryMcGill UniversityMontrealQuebecCanada,INSERM U1114University of StrasbourgStrasbourgFrance
| | - Marion Sourty
- INSERM U1114University of StrasbourgStrasbourgFrance,Laboratory of Engineering, Informatics and Imaging (ICube), Integrative Multimodal Imaging in Healthcare Team (IMIS), CNRS UMR 7357University of StrasbourgStrasbourgFrance
| | - Md Toufiqur Rahman
- Center for Drug DiscoveryResearch Triangle InstituteResearch Triangle ParkNorth CarolinaUSA
| | - Ann M. Decker
- Center for Drug DiscoveryResearch Triangle InstituteResearch Triangle ParkNorth CarolinaUSA
| | - Chunyang Jin
- Center for Drug DiscoveryResearch Triangle InstituteResearch Triangle ParkNorth CarolinaUSA
| | - Brigitte L. Kieffer
- Douglas Mental Health University InstituteMontrealQuebecCanada,Department of PsychiatryMcGill UniversityMontrealQuebecCanada,INSERM U1114University of StrasbourgStrasbourgFrance
| |
Collapse
|
4
|
Rahman MT, Decker AM, Langston TL, Mathews KM, Laudermilk L, Maitra R, Ma W, Darcq E, Kieffer BL, Jin C. Design, Synthesis, and Structure-Activity Relationship Studies of (4-Alkoxyphenyl)glycinamides and Bioisosteric 1,3,4-Oxadiazoles as GPR88 Agonists. J Med Chem 2020; 63:14989-15012. [PMID: 33205975 PMCID: PMC7737621 DOI: 10.1021/acs.jmedchem.0c01581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Increasing evidence implicates the orphan G protein-coupled receptor 88 (GPR88) in a number of striatal-associated disorders. In this study, we report the design and synthesis of a series of novel (4-alkoxyphenyl)glycinamides (e.g., 31) and the corresponding 1,3,4-oxadiazole bioisosteres derived from the 2-AMPP scaffold (1) as GPR88 agonists. The 5-amino-1,3,4-oxadiazole derivatives (84, 88-90) had significantly improved potency and lower lipophilicity compared to 2-AMPP. Compound 84 had an EC50 of 59 nM in the GPR88 overexpressing cell-based cAMP assay. In addition, 84 had an EC50 of 942 nM in the [35S]GTPγS binding assay using mouse striatal membranes but was inactive in membranes from GPR88 knockout mice, even at a concentration of 100 μM. In vivo pharmacokinetic testing of 90 in rats revealed that the 5-amino-1,3,4-oxadiazole analogues may have limited brain permeability. Taken together, these results provide the basis for further optimization to develop a suitable agonist to probe GPR88 functions in the brain.
Collapse
Affiliation(s)
- Md Toufiqur Rahman
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Ann M. Decker
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Tiffany L. Langston
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Kelly M. Mathews
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Lucas Laudermilk
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Rangan Maitra
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States
| | - Weiya Ma
- Douglas Research Center, Department of Psychiatry, McGill University, Montréal, Quebec H4H 1R3, Canada
| | - Emmanuel Darcq
- Douglas Research Center, Department of Psychiatry, McGill University, Montréal, Quebec H4H 1R3, Canada,INSERM U1114, University of Strasbourg, Strasbourg 67085, France
| | - Brigitte L. Kieffer
- Douglas Research Center, Department of Psychiatry, McGill University, Montréal, Quebec H4H 1R3, Canada,INSERM U1114, University of Strasbourg, Strasbourg 67085, France
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina, 27709, United States,Corresponding author: Dr. Chunyang Jin, Research Triangle Institute, Post Office Box 12194, Research Triangle Park, NC 27709, Telephone: 919 541-6328, Fax: 919 541-8868,
| |
Collapse
|
5
|
Ye N, Li B, Mao Q, Wold EA, Tian S, Allen JA, Zhou J. Orphan Receptor GPR88 as an Emerging Neurotherapeutic Target. ACS Chem Neurosci 2019; 10:190-200. [PMID: 30540906 DOI: 10.1021/acschemneuro.8b00572] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although G protein-coupled receptors (GPCRs) are recognized as pivotal drug targets involved in multiple physiological and pathological processes, the majority of GPCRs including orphan GPCRs (oGPCRs) are unexploited. GPR88, a brain-specific oGPCR with particularly robust expression in the striatum, regulates diverse brain and behavioral functions, including cognition, mood, movement control, and reward-based learning, and is thus emerging as a novel drug target for central nervous system disorders including schizophrenia, Parkinson's disease, anxiety, and addiction. Nevertheless, no effective GPR88 synthetic ligands have yet entered into clinical trials, and GPR88 endogenous ligands remain unknown. Despite the recent discovery and early stage study of several GPR88 agonists, such as 2-PCCA, RTI-13951-33, and phenylglycinol derivatives, further research into GPR88 pharmacology, medicinal chemistry, and chemical biology is urgently needed to yield structurally diversified GPR88-specific ligands. Drug-like pharmacological tool function and relevant signaling elucidation will also accelerate the evaluation of this receptor as a viable neurotherapeutic target.
Collapse
Affiliation(s)
- Na Ye
- Department of Medicinal Chemistry, Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Bang Li
- Department of Medicinal Chemistry, Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - Qi Mao
- Department of Medicinal Chemistry, Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - Eric A. Wold
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sheng Tian
- Department of Medicinal Chemistry, Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - John A. Allen
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| |
Collapse
|
6
|
Ehrlich AT, Semache M, Bailly J, Wojcik S, Arefin TM, Colley C, Le Gouill C, Gross F, Lukasheva V, Hogue M, Darcq E, Harsan LA, Bouvier M, Kieffer BL. Mapping GPR88-Venus illuminates a novel role for GPR88 in sensory processing. Brain Struct Funct 2018; 223:1275-1296. [PMID: 29110094 PMCID: PMC5871604 DOI: 10.1007/s00429-017-1547-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/17/2017] [Indexed: 01/20/2023]
Abstract
GPR88 is an orphan G-protein coupled receptor originally characterized as a striatal-enriched transcript and is a potential target for neuropsychiatric disorders. At present, gene knockout studies in the mouse have essentially focused on striatal-related functions and a comprehensive knowledge of GPR88 protein distribution and function in the brain is still lacking. Here, we first created Gpr88-Venus knock-in mice expressing a functional fluorescent receptor to fine-map GPR88 localization in the brain. The receptor protein was detected in neuronal soma, fibers and primary cilia depending on the brain region, and remarkably, whole-brain mapping revealed a yet unreported layer-4 cortical lamination pattern specifically in sensory processing areas. The unique GPR88 barrel pattern in L4 of the somatosensory cortex appeared 3 days after birth and persisted into adulthood, suggesting a potential function for GPR88 in sensory integration. We next examined Gpr88 knockout mice for cortical structure and behavioral responses in sensory tasks. Magnetic resonance imaging of live mice revealed abnormally high fractional anisotropy, predominant in somatosensory cortex and caudate putamen, indicating significant microstructural alterations in these GPR88-enriched areas. Further, behavioral analysis showed delayed responses in somatosensory-, visual- and olfactory-dependent tasks, demonstrating a role for GPR88 in the integration rather than perception of sensory stimuli. In conclusion, our data show for the first time a prominent role for GPR88 in multisensory processing. Because sensory integration is disrupted in many psychiatric diseases, our study definitely positions GPR88 as a target to treat mental disorders perhaps via activity on cortical sensory networks.
Collapse
Affiliation(s)
- Aliza T Ehrlich
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch-Graffenstaden, France
| | - Meriem Semache
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Julie Bailly
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
| | - Stefan Wojcik
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
- Department of Biochemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Tanzil M Arefin
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, USA
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch-Graffenstaden, France
| | - Christine Colley
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
- Department of Biochemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Christian Le Gouill
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Florence Gross
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Viktoriya Lukasheva
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Mireille Hogue
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Emmanuel Darcq
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada
| | - Laura-Adela Harsan
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg, CNRS, Strasbourg, France
- Department of Biophysics and Nuclear Medicine, Faculty of Medicine, University Hospital Strasbourg, Strasbourg, France
| | - Michel Bouvier
- Department of Biochemistry, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Brigitte L Kieffer
- Department of Psychiatry, McGill University, Douglas Hospital Research Center, Perry Pavilion Room E-3317.1, 6875 boulevard LaSalle, Montreal, QC, H4H 1R3, Canada.
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch-Graffenstaden, France.
| |
Collapse
|
7
|
Siemian JN, Xue Z, Blough BE, Li JX. Comparison of some behavioral effects of d- and l-methamphetamine in adult male rats. Psychopharmacology (Berl) 2017; 234:2167-2176. [PMID: 28386698 PMCID: PMC5482751 DOI: 10.1007/s00213-017-4623-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/29/2017] [Indexed: 02/07/2023]
Abstract
RATIONALE Both l- and d-methamphetamine (l- and d-MA) are more potent to release norpepinephrine (NE) than dopamine, and the selectivity is greater for l-MA than d-MA. Little is known of the in vivo pharmacology of l-MA. OBJECTIVE This study compared the effects of l-MA and d-MA in assays of nociception, behavioral disruption, and impulsivity. METHODS Antinociceptive effects of d- and l-MA were examined in two pain assays: the warm water tail withdrawal test for acute nociception and the von Frey test in complete Freund's adjuvant (CFA)-treated rats for chronic inflammatory pain. Food-maintained operant responding and locomotion tests were used to assess generalized behavioral disruption. The 5-choice serial reaction time test (5-CSRTT) was used to assess drug-induced effects on impulse control. A delay discounting procedure was used to determine drug-induced changes in sensitivity to reinforcer delay (impulsive choice). RESULTS l-MA (3.2-10 mg/kg) produced dose-dependent antinociception in both pain assays, decreased the rate of food-maintained operant responding, and decreased locomotor activity at a higher dose (17.8 mg/kg). In contrast, d-MA (0.32-3.2 mg/kg) did not produce antinociception in either assay, produced biphasic effects on response rate, and increased locomotor activity. In the 5-CSRTT, d-MA but not l-MA produced significant increase in premature responses. In the delay discounting procedure, both drugs did not affect the delay function at doses that did not increase omissions. CONCLUSIONS These data suggest that d- and l-MA have different behavioral profiles. Consideration should be given to these differences in future studies when l-MA is proposed for potential therapies.
Collapse
Affiliation(s)
- Justin N. Siemian
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Zhaoxia Xue
- Department of Medical Psychology, College of Humanities and Social Sciences, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Bruce E. Blough
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, Durham, North Carolina, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
8
|
Meirsman A, Le Merrer J, Pellissier L, Diaz J, Clesse D, Kieffer B, Becker J. Mice Lacking GPR88 Show Motor Deficit, Improved Spatial Learning, and Low Anxiety Reversed by Delta Opioid Antagonist. Biol Psychiatry 2016; 79:917-27. [PMID: 26188600 PMCID: PMC4670823 DOI: 10.1016/j.biopsych.2015.05.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/22/2015] [Accepted: 05/24/2015] [Indexed: 12/31/2022]
Abstract
BACKGROUND GPR88 is an orphan G protein coupled receptor highly enriched in the striatum, and previous studies have focused on GPR88 function in striatal physiology. The receptor is also expressed in other brain areas, and here we examined whether GPR88 function extends beyond striatal-mediated responses. METHODS We created Gpr88 knockout mice and examined both striatal and extrastriatal regions at molecular and cellular levels. We also tested striatum-, hippocampus-, and amygdala-dependent behaviors in Gpr88(-/-) mice using extensive behavioral testing. RESULTS We found increased G protein coupling for delta opioid receptor (DOR) and mu opioid, but not other Gi/o coupled receptors, in the striatum of Gpr88 knockout mice. We also found modifications in gene transcription, dopamine and serotonin contents, and dendritic morphology inside and outside the striatum. Behavioral testing confirmed striatal deficits (hyperactivity, stereotypies, motor impairment in rotarod). In addition, mutant mice performed better in spatial tasks dependent on hippocampus (Y-maze, novel object recognition, dual solution cross-maze) and also showed markedly reduced levels of anxiety (elevated plus maze, marble burying, novelty suppressed feeding). Strikingly, chronic blockade of DOR using naltrindole partially improved motor coordination and normalized spatial navigation and anxiety of Gpr88(-/-) mice. CONCLUSIONS We demonstrate that GPR88 is implicated in a large repertoire of behavioral responses that engage motor activity, spatial learning, and emotional processing. Our data also reveal functional antagonism between GPR88 and DOR activities in vivo. The therapeutic potential of GPR88 therefore extends to cognitive and anxiety disorders, possibly in interaction with other receptor systems.
Collapse
Affiliation(s)
- A.C. Meirsman
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U-964, CNRS UMR-7104, Université de Strasbourg, Illkirch, France
| | - J. Le Merrer
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U-964, CNRS UMR-7104, Université de Strasbourg, Illkirch, France, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université François Rabelais de Tours, Nouzilly, France
| | - L.P. Pellissier
- Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université François Rabelais de Tours, Nouzilly, France
| | - J. Diaz
- Centre de Psychiatrie et Neurosciences, INSERM UMR-894 - Université Paris Descartes, Paris, France
| | - D. Clesse
- Département de Neurobiologie des rythmes, Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR-3212, Université de Strasbourg, Strasbourg, France
| | - B.L. Kieffer
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U-964, CNRS UMR-7104, Université de Strasbourg, Illkirch, France
| | - J.A.J. Becker
- Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U-964, CNRS UMR-7104, Université de Strasbourg, Illkirch, France, Physiologie de la Reproduction et des Comportements, INRA UMR-0085, CNRS UMR-7247, Université François Rabelais de Tours, Nouzilly, France
| |
Collapse
|
9
|
Agmatine attenuates the discriminative stimulus and hyperthermic effects of methamphetamine in male rats. Behav Pharmacol 2016; 27:542-8. [PMID: 27232669 DOI: 10.1097/fbp.0000000000000244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Methamphetamine abuse remains an alarming public heath challenge, with no approved pharmacotherapies available. Agmatine is a naturally occurring cationic polyamine that has previously been shown to attenuate the rewarding and psychomotor-sensitizing effects of methamphetamine. This study examined the effects of agmatine on the discriminative stimulus and hyperthermic effects of methamphetamine. Adult male rats were trained to discriminate 0.32 mg/kg methamphetamine from saline. Methamphetamine dose dependently increased drug-associated lever responding. The nonselective dopamine receptor antagonist haloperidol (0.1 mg/kg) significantly attenuated the discriminative stimulus effects of methamphetamine (5.9-fold rightward shift). Agmatine (10-100 mg/kg) did not substitute for methamphetamine, but significantly attenuated the stimulus effects of methamphetamine, leading to a maximum of a 3.5-fold rightward shift. Acute 10 mg/kg methamphetamine increased the rectal temperature by a maximum of 1.96±0.17°C. Agmatine (10-32 mg/kg) pretreatment significantly attenuated the hyperthermic effect of methamphetamine. Agmatine (10 mg/kg) also significantly reversed methamphetamine-induced temperature increase. Together, these results support further exploration of the value that agmatine may have for the treatment of methamphetamine abuse and overdose.
Collapse
|
10
|
Local inactivation of Gpr88 in the nucleus accumbens attenuates behavioral deficits elicited by the neonatal administration of phencyclidine in rats. Mol Psychiatry 2015; 20:951-8. [PMID: 25155879 DOI: 10.1038/mp.2014.92] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 06/20/2014] [Accepted: 07/08/2014] [Indexed: 12/15/2022]
Abstract
Gpr88, an orphan G-protein-coupled receptor, is highly and almost exclusively expressed in the medium spiny projection neurons of the striatum, and may thus participate in the control of motor functions and cognitive processing that are impaired in neuropsychiatric disorders such as Parkinson's disease or schizophrenia (SZ). This study investigated the relevance of Gpr88 to SZ-associated behavior by knocking down Gpr88 gene expression in the ventral striatum (nucleus accumbens) in a neurodevelopmental rat model of SZ, generated by neonatal treatment with phencyclidine (PCP). In this model, we compared the effects of the local inactivation in the adult animal of the expression of Gpr88 and of Drd2, a gene strongly implicated in the etiology of SZ and coding for the dopamine receptor type 2 (D2). To inactivate specifically Gpr88 and D2 expression, we used the lentiviral vector-mediated microRNA silencing strategy. The neonatal PCP treatment induced in the adult rat hyperlocomotion in response to amphetamine (Amph) and social novelty discrimination (SND) deficits. The inactivation of D2 did not modify the locomotor response to Amph or the cognitive deficits induced by PCP, whereas the silencing of Gpr88 inhibited the Amph-induced hyperlocomotion and reduced the impairment of SND elicited by neonatal exposure to PCP. These observations suggest a role for Gpr88 in the regulation of cognitive and motor functions, and support its relevance to the pathophysiology and treatment of SZ and other disorders involving dysfunction of the accumbens-striatal complex.
Collapse
|
11
|
Qiu Y, Zhang Y, Li JX. Discriminative stimulus effects of the imidazoline I2 receptor ligands BU224 and phenyzoline in rats. Eur J Pharmacol 2015; 749:133-41. [PMID: 25617792 DOI: 10.1016/j.ejphar.2015.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 01/25/2023]
Abstract
Although imidazoline I2 receptor ligands have been used as discriminative stimuli, the role of efficacy of I2 receptor ligands as a critical determinant in drug discrimination has not been explored. This study characterized the discriminative stimulus effects of selective imidazoline I2 receptor ligands BU224 (a low-efficacy I2 receptor ligand) and phenyzoline (a higher efficacy I2 receptor ligand) in rats. Two groups of male Sprague-Dawley rats were trained to discriminate 5.6mg/kg BU224 or 32mg/kg phenyzoline (i.p.) from their vehicle in a two-lever food-reinforced drug discrimination procedure, respectively. All rats acquired the discriminations after an average of 18 (BU224) and 56 (phenyzoline) training sessions, respectively. BU224 and phenyzoline completely substituted for one another symmetrically. Several I2 receptor ligands (tracizoline, CR4056, RS45041, and idazoxan) all occasioned>80% drug-associated lever responding in both discriminations. The I2 receptor ligand 2-BFI and a monoamine oxidase inhibitor harmane occasioned>80% drug-associated lever responding in rats discriminating BU224. Other drugs that occasioned partial or less substitution to BU224 cue included clonidine, methamphetamine, ketamine, morphine, methadone and agmatine. Clonidine, methamphetamine and morphine also only produced partial substitution to phenyzoline cue. Naltrexone, dopamine D2 receptor antagonist haloperidol and serotonin (5-HT)2A receptor antagonist MDL100907 failed to alter the discriminative stimulus effects of BU224 or phenyzoline. Combined, these results are the first to demonstrate that BU224 and phenyzoline can serve as discriminative stimuli and that the low-efficacy I2 receptor ligand BU224 shares similar discriminative stimulus effects with higher-efficacy I2 receptor ligands such as phenyzoline and 2-BFI.
Collapse
Affiliation(s)
- Yanyan Qiu
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
12
|
Abstract
The imidazoline I2 receptor ligand BU99006 binds to and attenuates effects mediated by I2 receptors in vitro, although its effects in vivo have not been studied previously. This study examined the effects of BU99006 in two behavioral assays in rats: hypothermia and 2-BFI discrimination. BU99006 (3.2-15 mg/kg, intraperitoneally) produced a dose-dependent hypothermic effect (rectal temperature), which was antagonized by the I2 receptor antagonist idazoxan. BU99006 (3.2 or 10 mg/kg administered 10 min or 2 h before the session, respectively) did not significantly alter hypothermia produced by the I2 receptor agonist 2-BFI (10 mg/kg). In rats discriminating 5.6 mg/kg 2-BFI, BU99006 (1.78-17.8 mg/kg, intraperitoneally) produced 40 and 82% responding on the 2-BFI-associated lever when it was administered immediately or 2 h before the test sessions, respectively. BU99006 enhanced the discriminative stimulus and rate-suppressing effects of 2-BFI. Collectively, these data suggest that BU99006 is an imidazoline I2 receptor agonist with no evidence of I2 receptor antagonism in rats.
Collapse
|
13
|
Qiu Y, He XH, Zhang Y, Li JX. Discriminative stimulus effects of the novel imidazoline I₂ receptor ligand CR4056 in rats. Sci Rep 2014; 4:6605. [PMID: 25308382 PMCID: PMC4194429 DOI: 10.1038/srep06605] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/22/2014] [Indexed: 01/27/2023] Open
Abstract
This study examined whether a novel imidazoline I2 receptor ligand CR4056 could serve as a discriminative stimulus and whether it shares similar discriminative stimulus effects with other reported I2 receptor ligands. Eight male Sprague-Dawley rats were trained to discriminate 10.0 mg/kg CR4056 (i.p.) from vehicle in a two-lever food-reinforced drug discrimination procedure. Once rats acquired the discrimination, substitution and combination studies were conducted to elucidate the underlying receptor mechanisms. All rats acquired CR4056 discrimination after an average of 26 training sessions. Several I2 receptor ligands (phenyzoline, tracizoline, RS45041, and idazoxan, 3.2–75 mg/kg, i.p.) all occasioned > 80% CR4056-associated lever responding. Other drugs that occasioned partial or no CR4056-associated lever responding included methamphetamine, ketamine, the endogenous imidazoline ligand agmatine, the monoamine oxidase (MAO) inhibitor harmane, the α2-adrenoceptor agonist clonidine, the μ-opioid receptor agonists morphine and methadone, and the selective I2 receptor ligands BU224 and 2-BFI. The α1 adrenoceptor antagonist WB4101, α2 adrenoceptor antagonist yohimbine and μ-opioid receptor antagonist naltrexone failed to alter the stimulus effects of CR4056. Together, these results show that CR4056 can serve as a discriminative stimulus in rats, which demonstrates high pharmacological specificity and appears to be mediated by imidazoline I2 receptors.
Collapse
Affiliation(s)
- Yanyan Qiu
- 1] Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA [2] Department of Physiology, School of Basic Medical Sciences, Wuhan University, Hubei, China
| | - Xiao-Hua He
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Hubei, China
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| |
Collapse
|
14
|
The trace amine associated receptor 1 agonist RO5263397 attenuates the induction of cocaine behavioral sensitization in rats. Neurosci Lett 2014; 566:67-71. [PMID: 24561093 DOI: 10.1016/j.neulet.2014.02.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 11/23/2022]
Abstract
The trace amine associated receptor (TAAR) 1 is a new G protein coupled receptor that critically modulates central dopaminergic system. Recently, several selective TAAR 1 ligands have been described to possess antipsychotic and antidepressant-like activities. However, it is unknown of the role of these ligands in modulating psychostimulant-induced neurobehavioral plasticity. This study examined the effects of a selective TAAR 1 agonist, RO5263397, on cocaine induced behavioral sensitization in rats, a rodent model of drug-induced behavioral plasticity. Daily treatment with 15mg/kg cocaine (i.p., 7 days) induced robust locomotor sensitization in rats. RO5263397 (1-10mg/kg, i.p.) alone did not significantly alter the locomotor activity. Acute treatment with RO5263397 (3.2 and 10mg/kg) did not significantly modify cocaine-induced hyperactivity; however, the induction of locomotor sensitization was significantly blocked after 7 days of daily RO5263397 treatment. More importantly, the expression of locomotor sensitization remained significantly attenuated when rats were re-tested 7 days after the last drug treatment. The marked attenuation of cocaine sensitization was also evidenced by the suppression of the dose-effect function (3.2-32mg/kg) of cocaine sensitization. Together, these data represent the first to report a critical modulatory role of TAAR 1 agonists in cocaine-induced behavioral plasticity, which may be indicative of its potential role for altering other long-lasting behavioral maladaptations of cocaine including drug addiction.
Collapse
|