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Ruiz-Viroga V, de Ceglia M, Morelli L, Castaño EM, Calvo EB, Suárez J, Rodríguez de Fonseca F, Galeano P, Lagos P. Acute intrahippocampal administration of melanin-concentrating hormone impairs memory consolidation and decreases the expression of MCHR-1 and TrkB receptors. Prog Neuropsychopharmacol Biol Psychiatry 2023; 123:110703. [PMID: 36565982 DOI: 10.1016/j.pnpbp.2022.110703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Interest in the role of melanin-concentrating hormone (MCH) in memory processes has increased in recent years, with some studies reporting memory-enhancing effects, while others report deleterious effects. Due to these discrepancies, this study seeks to provide new evidence about the role of MCH in memory consolidation and its relation with BDNF/TrkB system. To this end, in the first experiment, increased doses of MCH were acutely administered in both hippocampi to groups of male rats (25, 50, 200, and 500 ng). Microinjections were carried out immediately after finishing the sample trial of two hippocampal-dependent behavioral tasks: the Novel Object Recognition Test (NORT) and the modified Elevated Plus Maze (mEPM) test. Results indicated that a dose of 200 ng of MCH or higher impaired memory consolidation in both tasks. A second experiment was performed in which a dose of 200 ng of MCH was administered alone or co-administered with the MCHR-1 antagonist ATC-0175 at the end of the sample trial in the NORT. Results showed that MCH impaired memory consolidation, while the co-administration with ATC-0175 reverted this detrimental effect. Moreover, MCH induced a significant decrease in hippocampal MCHR-1 and TrkB expression with no modification in the expression of BDNF and NMDA receptor subunits NR1, NR2A, and NR2B. These results suggest that MCH in vivo elicits pro-amnesic effects in the rat hippocampus by decreasing the availability of its receptor and TrkB receptors, thus linking both endogenous systems to memory processes.
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Affiliation(s)
- Vicente Ruiz-Viroga
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Gral. Flores 2125, Montevideo ZP11800, Uruguay
| | - Marialuisa de Ceglia
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Av. Carlos Haya 82, Málaga 29010, Spain.
| | - Laura Morelli
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Eduardo M Castaño
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Eduardo Blanco Calvo
- Instituto de Investigación Biomédica de Málaga (IBIMA), Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, Campus de Teatinos S/N, Málaga 29071, Spain.
| | - Juan Suárez
- Instituto de Investigación Biomédica de Málaga (IBIMA), Departamento de Anatomía Humana, Medicina Legal e Historia de la Ciencia, Universidad de Málaga, Málaga 29071, Spain.
| | - Fernando Rodríguez de Fonseca
- UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Universidad de Málaga, Av. Carlos Haya 82, Málaga 29010, Spain.
| | - Pablo Galeano
- Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir (IIBBA-CONICET), Av. Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires C1405BWE, Argentina.
| | - Patricia Lagos
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Gral. Flores 2125, Montevideo ZP11800, Uruguay.
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Eberle AN, Mild G, Zumsteg U. Cellular models for the study of the pharmacology and signaling of melanin-concentrating hormone receptors. J Recept Signal Transduct Res 2010; 30:385-402. [PMID: 21083507 DOI: 10.3109/10799893.2010.524223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cellular models for the study of the neuropeptide melanin-concentrating hormone (MCH) have become indispensable tools for pharmacological profiling and signaling analysis of MCH and its synthetic analogues. Although expression of MCH receptors is most abundant in the brain, MCH-R(1) is also found in different peripheral tissues. Therefore, not only cell lines derived from nervous tissue but also from peripheral tissues that naturally express MCH receptors have been used to study receptor signaling and regulation. For screening of novel compounds, however, heterologous expression of MCH-R(1) or MCH-R(2) genes in HEK293, Chinese hamster ovary, COS-7, or 3T3-L1 cells, or amplified MCH-R(1) expression/signaling in IRM23 cells transfected with the G(q) protein gene are the preferred tools because of more distinct pharmacological effects induced by MCH, which include inhibition of cAMP formation, stimulation of inositol triphosphate production, increase in intracellular free Ca(2+) and/or activation of mitogen-activated protein kinases. Most of the published data originate from this type of model system, whereas data based on studies with cell lines endogenously expressing MCH receptors are more limited. This review presents an update on the different cellular models currently used for the analysis of MCH receptor interaction and signaling.
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Affiliation(s)
- Alex N Eberle
- Laboratory of Endocrinology, Department of Biomedicine, University Hospital and University Children's Hospital, University of Basel, Basel, Switzerland
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3
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Chung S, Saito Y, Civelli O. MCH receptors/gene structure-in vivo expression. Peptides 2009; 30:1985-9. [PMID: 19647772 PMCID: PMC2764003 DOI: 10.1016/j.peptides.2009.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 11/17/2022]
Abstract
Melanin-concentrating hormone (MCH) is a cyclic peptide which was originally discovered in fish to lighten skin color by affecting melanosomes aggregation. This peptide is highly conserved and also found in rodents whose gene is overexpressed upon fasting. However, the site of MCH action remained obscure until its receptor was discovered in 1999 as a G protein-coupled receptor. After this receptor structure was identified, the functional domains important for MCH-MCHR interaction were revealed. Moreover, the cloning of the MCH receptor led us to identify the in vivo sites of MCH action which suggested potential physiological functions of the MCH system. Furthermore, the MCH receptor identification allow for designing surrogate molecules which can block MCH activity. Studies using these molecules revealed various physiological functions of the MCH system not only in feeding but also in other physiological responses such as stress and emotion. This review will discuss how the MCH receptor was discovered and its impact on many studies investigating the MCH receptor's structure, signaling pathways, and expression pattern.
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Affiliation(s)
- Shinjae Chung
- Department of Pharmacology, University of California, Irvine, Irvine, CA, USA
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
| | - Yumiko Saito
- Laboratory for Behavioral Neuroscience, Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Olivier Civelli
- Department of Pharmacology, University of California, Irvine, Irvine, CA, USA
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, USA
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4
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Lakaye B, Coumans B, Harray S, Grisar T. Melanin-concentrating hormone and immune function. Peptides 2009; 30:2076-80. [PMID: 19450627 DOI: 10.1016/j.peptides.2009.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 05/04/2009] [Accepted: 05/05/2009] [Indexed: 10/20/2022]
Abstract
To date, melanin-concentrating hormone (MCH) has been generally considered as peptide acting almost exclusively in the central nervous system. In the present paper, we revise the experimental evidence, demonstrating that MCH and its receptors are expressed by cells of the immune system and directly influence the response of these cells in some circumstances. This therefore supports the idea that, as with other peptides, MCH could be considered as a modulator of the immune system. Moreover, we suggest that this could have important implications in several immune-mediated disorders and affirm that there is a clear need for further investigation.
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Varas MM, Pérez MF, Ramírez OA, de Barioglio SR. Increased susceptibility to LTP generation and changes in NMDA-NR1 and -NR2B subunits mRNA expression in rat hippocampus after MCH administration. Peptides 2003; 24:1403-11. [PMID: 14706556 DOI: 10.1016/j.peptides.2003.09.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The present study attempts to determine which mechanisms underlie the retrograde facilitation of memory induced by microinjection hippocampal melanin-concentrating hormone (MCH) on the inhibitory avoidance paradigm. Previous reports using this test on the hippocampus suggest that NMDA receptor-mediated mechanisms are involved in memory processing and are also necessary for the induction of long-term potentiation (LTP) of the hippocampal dentate gyrus. In addition, alterations in expression of synaptic NMDA subunits in the hippocampus have been associated with memory formation of an inhibitory avoidance task. We have studied the effects of the neuropeptide upon the electrophysiological parameters using hippocampal slices from rats injected with the peptide and tested in step-down tests as well as possible changes in the mRNA expression of NMDA receptor subunits. We postulate that the increased facility to induce LTP, and the overexpression of this N-methyl-D-aspartate mRNA receptor subunits induced by MCH, could be behind the retrograde facilitation observed after MCH hippocampal microinjection.
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Affiliation(s)
- Mariana Marcela Varas
- Departamento de Farmacología, Facultad de Ciencias Químicas, Haya de La Torre esq. Medina Allende, Universidad Nacional de Córdoba, Córdoba 5000, Argentina.
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Varas M, Pérez M, Monzón ME, de Barioglio SR. Melanin-concentrating hormone, hippocampal nitric oxide levels and memory retention. Peptides 2002; 23:2213-21. [PMID: 12535701 DOI: 10.1016/s0196-9781(02)00252-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The present study attempts to determine, if the effect of melanin-concentrating hormone (MCH) upon memory retention is correlated with changes in nitric oxide synthase (NOS) activity and tissue levels of nitric oxide (NO) and cGMP. We used a behavioral experiment using a step-down inhibitory avoidance test, the biochemical determinations of NO and cGMP, and electrophysiological model. Results of behavioral studies (step-down test) showed that MCH administration reverts the amnesic effects induced by N(G)-nitro-L-arginine (L-NOArg). Moreover, electrophysiological studies demonstrated that L-NOArg did not block the potentiation induced by the peptide. Hippocampal NO and cGMP levels increased after MCH injection.
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Affiliation(s)
- Mariana Varas
- Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
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7
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Audinot V, Lahaye C, Suply T, Rovère-Jovène C, Rodriguez M, Nicolas JP, Beauverger P, Cardinaud B, Galizzi JP, Fauchère JL, Nahon JL, Boutin JA. SVK14 cells express an MCH binding site different from the MCH1 or MCH2 receptor. Biochem Biophys Res Commun 2002; 295:841-8. [PMID: 12127971 DOI: 10.1016/s0006-291x(02)00763-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Melanin-concentrating hormone (MCH) is a cyclic peptide, mainly involved in the regulation of skin pigmentation in teleosts and feeding behavior in mammals. The human keratinocyte SVK14 cell line has been previously shown to express binding sites for the MCH analog [125I]-[Phe13,3-iodo-Tyr19]MCH. We report here that: (1) this binding site similarly recognized [125I]-[3-iodo-Tyr13]MCH; (2) its pharmacological profile clearly differed from those observed at the two human MCH receptor subtypes, MCH1-R and MCH2-R; (3) MCH did not induce any effect on second messenger systems (including cAMP, calcium, and MAP kinase signaling pathways), and (4) no mRNAs corresponding to the MCH receptors were found. In conclusion, the binding site characterized in the SVK14 cell line is distinct from the MCH1 and MCH2 receptors and deserves therefore further investigation.
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Affiliation(s)
- Valérie Audinot
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125, Chemin de Ronde, Croissy-sur-Seine, France
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8
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Boutin JA, Suply T, Audinot V, Rodriguez M, Beauverger P, Nicolas JP, Galizzi JP, Fauchère JL. Melanin-concentrating hormone and its receptors: state of the art. Can J Physiol Pharmacol 2002; 80:388-95. [PMID: 12056544 DOI: 10.1139/y02-056] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Melanin-concentrating hormone (MCH) is a cyclic neuropeptide of nineteen amino acids in mammals. Its involvement in the feeding behaviour has been well established during the last few years. A first receptor subtype, now termed MCHIR, was discovered in 1999, following the desorphanisation of the SLCI orphan receptor, using either reverse pharmacology or systematic screening of agonist candidates. A second MCH receptor, MCH2R, has been discovered recently, by several groups working on data mining of genomic banks. The molecular pharmacology of these two receptors is only described on the basis of the action of peptides derived from MCH. The present review tentatively summarizes the knowledge on these two receptors and presents the first attempts to discover new classes of antagonists that might have major roles in the control of obesity and feeding behaviour.
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Affiliation(s)
- Jean A Boutin
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, Croissy-sur-Seine, France.
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Schlumberger SE, Talke-Messerer C, Zumsteg U, Eberle AN. Expression of receptors for melanin-concentrating hormone (MCH) in different tissues and cell lines. J Recept Signal Transduct Res 2002; 22:509-31. [PMID: 12503638 DOI: 10.1081/rrs-120014618] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Melanin-concentrating hormone (MCH) is a potent orexigenic neuropeptide and a physiological antagonist of alpha-melanocyte-stimulating hormone (alpha-MSH) in the brain as well as at peripheral sites, including the pigmentary systems of specific vertebrates. Two receptor subtypes for MCH, MCH-R1 and MCH-R2, have been cloned, but other receptor subtypes are likely to exist. Based on our own data and the current literature, we have compared the expression of different receptors for MCH in various mammalian cell lines and tissues. Summarizing all data currently available, we conclude that the two cloned MCH receptors, MCH-R1 and MCH-R2, exhibit differences in their expression pattern, although MCH-R1 is generally colocalized in all tissues where MCH-R2 expression is found. It appears that MCH-R1 is more abundant and has a wider distribution pattern than MCH-R2. Other hypothetical MCH-R subtypes may be expressed in specific tissues, e.g., in the pigment cell system.
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Affiliation(s)
- Sophie E Schlumberger
- Laboratory of Endocrinology, Department of Research (ZLF) University Hospital and University Children's Hospital, CH-4031 Basel, Switzerland
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10
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Chapter II The melanin-concentrating hormone. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0924-8196(02)80004-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Varas M, Pérez M, Ramírez O, de Barioglio SR. Melanin concentrating hormone increase hippocampal synaptic transmission in the rat. Peptides 2002; 23:151-5. [PMID: 11814630 DOI: 10.1016/s0196-9781(01)00591-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A retrograde facilitation has been demonstrated in the one trial step-down inhibitory avoidance of melanin-concentrating hormone (MCH), when it was infused into rat hippocampal formation. Considering the high density of specific binding sites for the MCH peptide on the hippocampus and the participation of this structure on learning and memory processes we have studied the effects of MCH on the hippocampal synaptic transmission. For this purpose, slices of rat hippocampus were perfused with different concentration of MCH. The main result of the present study was a long-lasting potentiation on the hippocampal evoked response on dentate gyrus induced by MCH (4-11 microM) at 30, 60 and 120 min with a maximum effect at 120 min. Previous perfusion of DL - 2- amino - 5 phosphonovaleric acid (APV, 20 microM) was unable to impair the increased hippocampal evoked response induced by MCH 4 microM. On the other hand, the channel blocker Dizocilpine (MK-801, 10 microM) completely impaired the increased hippocampal synaptic plasticity induced by MCH perfusion. We postulate the increased hippocampal synaptic efficacy induced by MCH as one of the mechanisms underlying the retrograde facilitation on the inhibitory avoidance paradigm, observed after MCH hippocampal microinjection. We cannot rule out other MCH neurochemical mechanism and other areas of the brain involved in the MCH effects.
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Affiliation(s)
- Mariana Varas
- Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
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12
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Audinot V, Lahaye C, Suply T, Beauverger P, Rodriguez M, Galizzi JP, Fauchère JL, Boutin JA. [125I]-S36057: a new and highly potent radioligand for the melanin-concentrating hormone receptor. Br J Pharmacol 2001; 133:371-8. [PMID: 11375253 PMCID: PMC1572795 DOI: 10.1038/sj.bjp.0704085] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Shortened, more stable and weakly hydrophobic analogues of melanin-concentrating hormone (MCH) were searched as candidates for radioiodination. Starting from the dodecapeptide MCH(6 - 17), we found that: (1) substitution of Tyr(13) by a Phe residue; (2) addition of a 3-iodo-Tyr residue at the N-terminus; and (3) addition of a hydrophilic spacer 8-amino-3,6-dioxyoctanoyl between the 3-iodo-Tyr and MCH(6 - 17) (compound S36057), led to an agonist more potent than MCH itself in stimulating [35S]-GTPgammaS binding at membranes from HEK293 cells stably expressing the human MCH receptor. Specific binding of [125I]-S36057 was found in HEK293 and CHO cell lines stably expressing the human MCH receptor. This radioligand recognized a similar number of binding sites (ca. 800 fmol mg(-1)) than [125I]-[3-iodo Tyr(13)]-MCH. However, the K(D) for [125I]-S36057 obtained from saturation studies (0.037 nM) or from binding kinetics (0.046 nM) was at least 10 fold higher to that of [125I]-[3-iodo Tyr(13)]-MCH (0.46 nM). Affinities determined for a series of MCH analogues were similar with both radioligands, S36057 being the most potent compound tested (K(i)=0.053 nM). Finally, [125I]-S36057 also potently labelled the MCH receptor in membranes from whole rat brain (K(D) 0.044 nM, B(max)=11 fmol mg(-1)). In conclusion, [125I]-S36057 is a more potent and more stable radioligand than [125I]-[3-iodo Tyr(13)]-MCH that will represent a reliable tool for binding assays in the search of novel MCH ligands. It should also provide great help for autoradiographic studies of the MCH receptor distribution in the central nervous system.
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Affiliation(s)
- Valérie Audinot
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Chantal Lahaye
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Thomas Suply
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Philippe Beauverger
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Marianne Rodriguez
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Jean-Pierre Galizzi
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
| | - Jean-Luc Fauchère
- Division des Peptides et de Chimie Combinatoire, Institut de Recherches Servier, 11, rue des Moulineaux, 92150 Suresnes, France
| | - Jean A Boutin
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy sur Seine, France
- Author for correspondence:
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Monzón ME, Varas MM, De Barioglio SR. Anxiogenesis induced by nitric oxide synthase inhibition and anxiolytic effect of melanin-concentrating hormone (MCH) in rat brain. Peptides 2001; 22:1043-7. [PMID: 11445232 DOI: 10.1016/s0196-9781(01)00439-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this study, the involvement of nitric oxide (NO) in the mechanism of anxiety was investigated. The rats received an intraamygdaline or intrahippocampal injection of the nitric oxide synthase inhibitor, N(G)-nitro-l-arginine (L-NOARG), and were then tested in the plus-maze test. L-NOARG induced a decrease in the time spent by rats in the open arms. Conversely, the administration of the melanin-concentrating hormone (MCH) into these structures increased the number of entries into the open arms as well as the time spent on them. MCH injected in rats pretreated with L-NOARG also was able to revert the anxiogenic effects of L-NOARG in amygdala.
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Affiliation(s)
- M E Monzón
- Laboratorio de Fisiología, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba (UNC), 5000 Córdoba, Argentina.
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14
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Audinot V, Beauverger P, Lahaye C, Suply T, Rodriguez M, Ouvry C, Lamamy V, Imbert J, Rique H, Nahon JL, Galizzi JP, Canet E, Levens N, Fauchere JL, Boutin JA. Structure-activity relationship studies of melanin-concentrating hormone (MCH)-related peptide ligands at SLC-1, the human MCH receptor. J Biol Chem 2001; 276:13554-62. [PMID: 11278733 DOI: 10.1074/jbc.m010727200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Melanin-concentrating hormone (MCH) is a cyclic nonadecapeptide involved in the regulation of feeding behavior, which acts through a G protein-coupled receptor (SLC-1) inhibiting adenylcyclase activity. In this study, 57 analogues of MCH were investigated on the recently cloned human MCH receptor stably expressed in HEK293 cells, on both the inhibition of forskolin-stimulated cAMP production and guanosine-5'-O-(3-[(35)S]thiotriphosphate ([(35)S]- GTPgammaS) binding. The dodecapeptide MCH-(6-17) (MCH ring between Cys(7) and Cys(16), with a single extra amino acid at the N terminus (Arg(6)) and at the C terminus (Trp(17))) was found to be the minimal sequence required for a full and potent agonistic response on cAMP formation and [(35)S]- GTPgammaS binding. We Ala-scanned this dodecapeptide and found that only 3 of 8 amino acids of the ring, namely Met(8), Arg(11), and Tyr(13), were essential to elicit full and potent responses in both tests. Deletions inside the ring led either to inactivity or to poor antagonists with potencies in the micromolar range. Cys(7) and Cys(16) were substituted by Asp and Lys or one of their analogues, in an attempt to replace the disulfide bridge by an amide bond. However, those modifications were deleterious for agonistic activity. In [(35)S]- GTPgammaS binding, these compounds behaved as weak antagonists (K(B) 1-4 microm). Finally, substitution in MCH-(6-17) of 6 out of 12 amino acids by non-natural residues and concomitant replacement of the disulfide bond by an amide bond led to three compounds with potent antagonistic properties (K(B) = 0.1-0.2 microm). Exploitation of these structure-activity relationships should open the way to the design of short and stable MCH peptide antagonists.
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Affiliation(s)
- V Audinot
- Division de Pharmacologie Moléculaire et Cellulaire, Institut de Recherches SERVIER, 78290-Croissy sur Seine, France
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15
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Hintermann E, Tanner H, Talke-Messerer C, Schlumberger S, Zumsteg U, Eberle AN. Interaction of melanin-concentrating hormone (MCH), neuropeptide E-I (NEI), neuropeptide G-E (NGE), and alpha-MSH with melanocortin and MCH receptors on mouse B16 melanoma cells. J Recept Signal Transduct Res 2001; 21:93-116. [PMID: 11693176 DOI: 10.1081/rrs-100107145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Melanin-concentrating hormone (MCH) and alpha-melanocyte-stimulating hormone (alpha-MSH) are known to exhibit mostly functionally antagonistic, but in some cases agonistic activities, e.g., in pigment cells and in the brain. Neuropeptide E-I (NEI) displays functional MCH-antagonist and MSH-agonist activity in different behavioral paradigms; the role of neuropeptide G-E (NGE) is not known. This study addressed the question of possible molecular interactions between alpha-MSH, MCH and the MCH-precursor-derived peptides NEI and NGE at the level of the pigment cell MCH receptor subtype (MCH-Rpc) and the different melanocortin (MC) receptors. Radioreceptor assays using [125I]MCH, [125l]alpha-MSH and [125I]NEI as radioligands and bioassays were performed with MCI-R-positive and MC1-R-negative mouse B16 melanoma cells and with COS cells expressing the different MC receptors. The IC50s of alpha-MSH and NEI or NGE for [125I]MCH displacement from mouse MCH-Rpc were 80-fold and, respectively, >300-fold higher than that of MCH, and the IC50s for MCH and NEI or NGE for [125I]alpha-MSH displacement from mouse MC1-R were 50,000-fold and >200,000-fold higher than that of alpha-MSH. No high-affinity binding sites for NEI were detected on B16 melanoma cells and there was no significant displacement of [1251]alpha-MSH by MCH, NEI or NGE with MC3-R, MC4-R and MC5-R expressed in COS cells. At concentrations of 100 nM to 10 microM, however, MCH, NEI and NGE induced cAMP formation and melanin synthesis which could be blocked by agouti protein or inhibitors of adenylate cyclase or protein kinase A. This shows that mammalian MCH-precursor-derived peptides may mimic MSH signalling via MC1-R activation at relatively high, but physiologically still relevant concentrations, as e.g. found in autocrine/paracrine signalling mechanisms.
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MESH Headings
- Animals
- Binding, Competitive
- COS Cells
- Gene Expression
- Humans
- Hypothalamic Hormones/metabolism
- Kinetics
- Melanins/biosynthesis
- Melanins/metabolism
- Melanoma, Experimental/metabolism
- Mice
- Oligopeptides/metabolism
- Peptide Fragments/metabolism
- Pituitary Hormones/metabolism
- Radioligand Assay
- Receptor, Melanocortin, Type 3
- Receptors, Corticotropin/classification
- Receptors, Corticotropin/genetics
- Receptors, Corticotropin/metabolism
- Receptors, Melanocortin
- Receptors, Pituitary Hormone/classification
- Receptors, Pituitary Hormone/genetics
- Receptors, Pituitary Hormone/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction
- Tumor Cells, Cultured
- alpha-MSH/metabolism
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Affiliation(s)
- E Hintermann
- Laboratory of Endocrinology, Department of Research (ZLF), University Hospital and University Children's Hospital, CH-4031 Basel, Switzerland
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Kastin AJ, Akerstrom V, Hackler L, Zadina JE. Phe(13),Tyr(19)-melanin-concentration hormone and the blood-brain barrier: role of protein binding. J Neurochem 2000; 74:385-91. [PMID: 10617143 DOI: 10.1046/j.1471-4159.2000.0740385.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Melanin-concentrating hormone (MCH), found both peripherally and centrally, is involved in food ingestion. Although its expression in brain is increased by fasting, it is not known whether it crosses the blood-brain barrier (BBB). Use of the sensitive method of multiple-time regression analysis has shown that almost all of the peptides and polypeptides tested cross the BBB at a rate faster than the vascular marker albumin. With this same method, however, we found that the 19-amino acid 125I-Phe13,Tyr19-MCH did not cross faster than 99mTc-albumin. Several mechanisms were excluded as possible explanations for the slow rate of influx. These included degradation, association with capillary endothelial cells, and transport from brain to blood. When Phe13,Tyr19-MCH was perfused in blood-free buffer, however, it entered the brain significantly faster than albumin. This suggested protein binding as an explanation for the slow rate of influx when the MCH was administered in blood. Protein binding was confirmed by capillary zone electrophoresis, which showed that almost all of the Phe13,Tyr19-MCH added to blood migrated with a large-molecular-weight substance. Sodium dodecyl sulfate-capillary gel electrophoresis of Phe13,Tyr19-MCH in buffer additionally showed that the MCH aggregated as a trimer, a factor not preventing its influx by blood-free perfusion. Thus, the results show that blood-borne Phe13,Tyr19-MCH does not significantly cross the BBB, probably because of its binding to serum proteins.
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Affiliation(s)
- A J Kastin
- VA Medical Center and Tulane University School of Medicine, New Orleans, Louisiana 70112-1262, USA
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17
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Monzon ME, de Souza MM, Izquierdo LA, Izquierdo I, Barros DM, de Barioglio SR. Melanin-concentrating hormone (MCH) modifies memory retention in rats. Peptides 1999; 20:1517-9. [PMID: 10698129 DOI: 10.1016/s0196-9781(99)00164-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The purpose of the present study was to evaluate the possible effect of melanin-concentrating hormone (MCH) on learning and memory by using the one-trial step-down inhibitory avoidance test in rats. The peptide was infused into hippocampus, amygdala, and entorhinal cortex. MCH caused retrograde facilitation when given at 0 or 4 h post-training into hippocampus, but only at 0 h into amygdala. From these results, it seems that MCH modulates memory early after training by acting on both the amygdala and hippocampus and, 4 h after training, on the hippocampus.
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Affiliation(s)
- M E Monzon
- Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
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Shimomura Y, Mori M, Sugo T, Ishibashi Y, Abe M, Kurokawa T, Onda H, Nishimura O, Sumino Y, Fujino M. Isolation and identification of melanin-concentrating hormone as the endogenous ligand of the SLC-1 receptor. Biochem Biophys Res Commun 1999; 261:622-6. [PMID: 10441476 DOI: 10.1006/bbrc.1999.1104] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Melanin-concentrating hormone (MCH), which is an orexigenic peptide, was isolated and identified as the endogenous ligand of the SLC-1 receptor. We established a CHO cell line expressing the rat SLC-1 receptor to search for its endogenous ligand. The extract of rat whole brain showed inhibition of intracellular forskolin-induced cAMP accumulation in rat SLC-1-expressing CHO cells and was purified. Using HPLC purification, we isolated and identified MCH as the endogenous ligand of the SLC-1 receptor. The authentic MCH demonstrated a dose-dependent inhibitory effect on cAMP accumulation in forskolin-stimulated rat and human SLC-1-expressing CHO cells with an EC(50) value of 0.2 nM for both the rat and human SLC-1 receptors. This is the first description of the functional receptor for MCH.
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Affiliation(s)
- Y Shimomura
- Pharmaceutical Discovery Research Division, Takeda Chemical Industries, Ltd., Wadai 10, Tsukuba, Ibaraki, 300-4293, Japan
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19
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Abstract
It is known that alpha-MSH augments cAMP levels in rat brain slices containing accumbens and caudate-putamen nuclei. In this study we examined: a) the effect of other neuropeptides: MCH and NEI, on this cyclic nucleotide; b) if the effects of alpha-MSH on cAMP production can be modulated by addition of MCH or NEI to the incubation medium. Both MCH and NEI (3.6 microM) increased the production of cAMP, whereas at doses of 0.6 microM exerted no effects. When alpha-MSH 0.6 microM was added with NEI or MCH (0.6 microM), only MCH blocked the increase in the cAMP induced by alpha-MSH. Neither MCH nor NEI at the highest dose used (3.6 microM) had any additive effect on AMPc when added together with alpha-MSH. We conclude that, at a high concentration, (MCH/NEI)-like peptides can use the intracellular signal transduction linked to cyclic nucleotides in the CNS.
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Affiliation(s)
- M S Sanchez
- Departamento de farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
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20
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Burgaud JL, Poosti R, Fehrentz JA, Martinez J, Nahon JL. Melanin-concentrating hormone binding sites in human SVK14 keratinocytes. Biochem Biophys Res Commun 1997; 241:622-9. [PMID: 9434758 DOI: 10.1006/bbrc.1997.7849] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Melanin concentrating hormone (MCH) is a cyclic peptide which regulates a broad array of functions in the mammalian brain and it may act as a paracrine factor in peripheral organs. In these studies a radiolabeled MCH derivative, the [125I]-[Phe13, Tyr19]-MCH, was synthesized and used as a tracer to perform binding experiments. A number of human or rodent cell lines displayed specific binding with [125I]-[Phe13, Tyr19]-MCH, the highest binding capacity being observed with human SVK14 keratinocytes. Saturation binding analysis with SVK14 cells indicated about 10,000 MCH binding sites per cell and a Kd of 0.7 nM for [125I]-[Phe13, Tyr19]-MCH. Surprisingly, the iodinated [Phe13, Tyr19]-MCH displayed about 10-fold higher affinity (Ki approximately 3.0 nM) for the putative MCH receptor than the noniodinated form (Ki approximately 25-30 nM). Competition binding analyses comparing various MCH-related peptides revealed a similar low binding potency for all these peptides (Ki approximately 65-160 nM). Strikingly, rat ANP and rat/human CNP but not rat BNP displaced [125I]-[Phe13, Tyr15]-MCH with Ki approximately 210-365 nM and may be due to topological similarities instead of partial sequence identities between MCH and some of the natriuretic peptides. However, other peptides such as CRF, alpha MSH, Arg-vasopressin, and MGOP-peptide I did not compete with the radioligand. Finally, the molecular mass of the MCH binding sites on SVK14 cells was estimated to be 47 kDa by crosslinking and SDS-PAGE experiments. Taken together, our data revealed the widespread expression of MCH binding sites on mammalian cells, particularly on skin carcinoma cells. However, the low affinity of these sites for the native MCH and MCH-related peptides as well as competitivity with ANP and CNP indicates that further biochemical and functional characterizations are needed to validate them as genuine physiological MCH receptors.
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Affiliation(s)
- J L Burgaud
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UPR 411, Valbonne, France
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21
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Abstract
Melanin concentrating hormone (MCH) is a 19 amino-acid peptide expressed in high concentrations within the dorso-lateral hypothalamus of rats, sheep and man. MCH regulates skin colour and ACTH release in teleost fish, however, its physiological relevance in mammals is unclear. The present study examined the cardiovascular and metabolic actions of intracerebroventricular (i.c.v.) infusion of MCH, and the pro-MCH derived peptide Neuropeptide-E-I (NEI), in conscious, chronically instrumented sheep. Human MCH (1-19) or NEI (1-13) was infused i.c.v. for 24 h into 6 sheep, and measurements were made every 10 min of arterial pressure, heart rate, cardiac output, stroke volume and peripheral blood flow/conductance. Recordings of water intake (H2Oin), urine volume (Uv), urinary Na (UNaV) and K excretion (UKV) were made, as well as hematocrit, plasma Na, K, osmolality, protein, glucose, ACTH, vasopressin, renin, endothelin, ANF, cortisol and aldosterone concentrations. After 24 h of infusion at 10 microg/h, MCH produced a significant increase in Uv from 0.8 +/- 0.2 to 1.4 +/- 0.3 l/day, together with an increase in UNaV from 56 +/- 8 to 107 +/- 14 mmol/day, and in UKV from 202 +/- 18 to 369 +/- 38 mmol/day. H2Oin was unchanged. Similar renal changes were observed during i.c.v. infusion of NEI. There was no change in any cardiovascular parameter, although hematocrit showed a large decrease with infusion of both peptides after 24 h infusion. Plasma osmolality increased from 291 +/- 1 to 295 +/- 1 mOsm/kg during MCH infusion, whereas total protein and plasma Na and K were unchanged. MCH increased plasma glucose from 3.4 +/- 0.2 to 3.8 +/- 0.2 mmol/l. Plasma aldosterone exhibited a 30-40% decrease following MCH or NEI infusion, whereas all other plasma concentrations remained unchanged. This study has shown that i.c.v. infusion of MCH or NEI can produce diuretic, natriuretic and kaliuretic changes in conscious sheep, triggered by a possible increase in plasma volume as indicated by the changes in hematocrit. These results, together with anatomical data reporting the presence of MCH/NEI in fluid regulatory areas of the brain, indicate that MCH/NEI may be an important peptide involved in the central control of fluid homeostasis in mammals.
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Affiliation(s)
- D G Parkes
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Australia
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