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Mani A, Salinas I. The knowns and many unknowns of CNS immunity in teleost fish. FISH & SHELLFISH IMMUNOLOGY 2022; 131:431-440. [PMID: 36241002 DOI: 10.1016/j.fsi.2022.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Many disease agents infect the central nervous system (CNS) of teleost fish causing severe losses for the fish farming sector. Yet, neurotropic fish pathogens remain poorly documented and immune responses in the teleost CNS essentially unknown. Previously thought to be devoid of an immune system, the mammalian CNS is now recognized to be protected from infection by diverse immune cells that mostly reside in the meningeal lymphatic system. Here we review the current body of work pertaining immune responses in the teleost CNS to infection. We identify important knowledge gaps with regards to CNS immunity in fish and make recommendations for rigorous experimentation and reporting in manuscripts so that fish immunologists can advance this burgeoning field.
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Affiliation(s)
- Amir Mani
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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2
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Bertolesi GE, McFarlane S. Melanin-concentrating hormone like and somatolactin. A teleost-specific hypothalamic-hypophyseal axis system linking physiological and morphological pigmentation. Pigment Cell Melanoma Res 2020; 34:564-574. [PMID: 32898924 DOI: 10.1111/pcmr.12924] [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] [Received: 05/22/2020] [Revised: 08/12/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022]
Abstract
Plastic adaptation to match the skin colour to the surrounding is key to survival. Two biological responses in skin colour are associated with background adaptation. A fast "physiological response" that aggregates/disperses the pigment organelles of skin chromatophores, and a slow "morphological response" that alters the type and/or density of pigment cells in the skin. Both responses are linked by unknown mechanisms. In this review, we discuss the role in skin colour regulation of two molecules that form part of a hypothalamic-hypophyseal pathway unique to teleosts, melanin-concentrating hormone "like" (MCHL) (previously known as MCH), and somatolactin. MCHL neurons project to the neurohypophysis and to the pars intermedia pituitary, where they interact with somatolactin-expressing cells. With a white background MCHL is released into the circulation to induce rapid melanosome aggregation and skin lightening. Somatolactin is also a fish-specific peptide whose expression and secretion are altered in organisms adapted chronically to white/black backgrounds, and that regulates morphological pigmentation. We discuss the evidence for a model whereby in teleosts, MCHL and somatolactin provide the previously unknown link between physiological and morphological pigmentation.
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Affiliation(s)
- Gabriel E Bertolesi
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Sarah McFarlane
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Song JA, Choi CY. Effects of blue light spectra on retinal stress and damage in goldfish (Carassius auratus). FISH PHYSIOLOGY AND BIOCHEMISTRY 2019; 45:391-400. [PMID: 30269261 DOI: 10.1007/s10695-018-0571-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 09/07/2018] [Indexed: 06/08/2023]
Abstract
There have been a number of studies on the negative effects of blue light exposure in various species; however, little information is available on the impacts of blue light intensity and duration on fish. We investigated the effects of blue light spectra on stress in the retinas of goldfish, using a blue (460 nm) light-emitting diode (LED) at three intensities (0.5, 1.0, and 1.5 W/m2). The experiment was conducted for 4 weeks, and sampling was performed at intervals of 1 week. We measured changes in the expression of cortisol, and the concentrations of hydrogen peroxide (H2O2), melanin-concentrating hormone receptor (MCH-R), and caspase-3 in the retinas of goldfish. In addition, we measured histological changes in the retina. We used a transferase dUTP nick end labeling (TUNEL) assay to evaluate the apoptotic response to blue LED spectra. Levels of cortisol, H2O2, MCH-R, and caspase-3 increased with exposure time and light intensity. Histological analysis revealed that the thickness of melanin granules increased with exposure time and light intensity. The progressive TUNEL assay revealed many apoptotic cells after exposure to blue LED light, increasing with exposure time and light intensity. Irradiation with blue light for longer than 1 week induced increased retinal stress and may induce apoptosis in the retinas of goldfish, even at a low intensity.
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Affiliation(s)
- Jin Ah Song
- Division of Marine BioScience, Korea Maritime and Ocean University, Busan, 49112, Republic of Korea
| | - Cheol Young Choi
- Division of Marine BioScience, Korea Maritime and Ocean University, Busan, 49112, Republic of Korea.
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4
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Héricé C, Patel AA, Sakata S. Circuit mechanisms and computational models of REM sleep. Neurosci Res 2018; 140:77-92. [PMID: 30118737 PMCID: PMC6403104 DOI: 10.1016/j.neures.2018.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/03/2018] [Accepted: 07/10/2018] [Indexed: 01/31/2023]
Abstract
REM sleep was discovered in the 1950s. Many hypothalamic and brainstem areas have been found to contribute to REM sleep. An up-to-date picture of REM-sleep-regulating circuits is reviewed. A brief overview of computational models for REM sleep regulation is provided. Outstanding issues for future studies are discussed.
Rapid eye movement (REM) sleep or paradoxical sleep is an elusive behavioral state. Since its discovery in the 1950s, our knowledge of the neuroanatomy, neurotransmitters and neuropeptides underlying REM sleep regulation has continually evolved in parallel with the development of novel technologies. Although the pons was initially discovered to be responsible for REM sleep, it has since been revealed that many components in the hypothalamus, midbrain, pons, and medulla also contribute to REM sleep. In this review, we first provide an up-to-date overview of REM sleep-regulating circuits in the brainstem and hypothalamus by summarizing experimental evidence from neuroanatomical, neurophysiological and gain- and loss-of-function studies. Second, because quantitative approaches are essential for understanding the complexity of REM sleep-regulating circuits and because mathematical models have provided valuable insights into the dynamics underlying REM sleep genesis and maintenance, we summarize computational studies of the sleep-wake cycle, with an emphasis on REM sleep regulation. Finally, we discuss outstanding issues for future studies.
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Affiliation(s)
- Charlotte Héricé
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Amisha A Patel
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Shuzo Sakata
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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Ferreira JGP, Bittencourt JC, Adamantidis A. Melanin-concentrating hormone and sleep. Curr Opin Neurobiol 2017; 44:152-158. [DOI: 10.1016/j.conb.2017.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/31/2017] [Accepted: 04/11/2017] [Indexed: 01/11/2023]
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6
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Gross JB, Powers AK, Davis EM, Kaplan SA. A pleiotropic interaction between vision loss and hypermelanism in Astyanax mexicanus cave x surface hybrids. BMC Evol Biol 2016; 16:145. [PMID: 27363593 PMCID: PMC4929771 DOI: 10.1186/s12862-016-0716-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/28/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Cave-dwelling animals evolve various traits as a consequence of life in darkness. Constructive traits (e.g., enhanced non-visual sensory systems) presumably arise under strong selective pressures. The mechanism(s) driving regression of features, however, are not well understood. Quantitative trait locus (QTL) analyses in Astyanax mexicanus Pachón cave x surface hybrids revealed phenotypic effects associated with vision and pigmentation loss. Vision QTL were uniformly associated with reductions in the homozygous cave condition, however pigmentation QTL demonstrated mixed phenotypic effects. This implied pigmentation might be lost through both selective and neutral forces. Alternatively, in this report, we examined if a pleiotropic interaction may exist between vision and pigmentation since vision loss has been shown to result in darker skin in other fish and amphibian model systems. RESULTS We discovered that certain members of Pachón x surface pedigrees are significantly darker than surface-dwelling fish. All of these "hypermelanic" individuals demonstrated severe visual system malformations suggesting they may be blind. A vision-mediated behavioral assay revealed that these fish, in stark contrast to surface fish, behaved the same as blind cavefish. Further, hypermelanic melanophores were larger and more dendritic in morphology compared to surface fish melanophores. However, hypermelanic melanophores responded normally to melanin-concentrating hormone suggesting darkening stemmed from vision loss, rather than a defect in pigment cell function. Finally, a number of genomic regions were coordinately associated with both reduced vision and increased pigmentation. CONCLUSIONS This work suggests hypermelanism in hybrid Astyanax results from blindness. This finding provides an alternative explanation for phenotypic effect studies of pigmentation QTL as stemming (at least in part) from environmental, rather than exclusively genetic, interactions between two regressive phenotypes. Further, this analysis reveals persistence of background adaptation in Astyanax. As the eye was lost in cave-dwelling forms, enhanced pigmentation resulted. Given the extreme cave environment, which is often devoid of nutrition, enhanced pigmentation may impose an energetic cost. Such an energetic cost would be selected against, as a means of energy conservation. Thus, the pleiotropic interaction between vision loss and pigmentation may reveal an additional selective pressure favoring the loss of pigmentation in cave-dwelling animals.
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Affiliation(s)
- Joshua B. Gross
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
- />Department of Biological Sciences, University of Cincinnati, Rieveschl Hall Room 711B, 312 Clifton Court, Cincinnati, Ohio 45221 USA
| | - Amanda K. Powers
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
| | - Erin M. Davis
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
| | - Shane A. Kaplan
- />Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45223 USA
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Alvisi RD, Diniz GB, Da-Silva JM, Bittencourt JC, Felicio LF. Suckling-induced Fos activation and melanin-concentrating hormone immunoreactivity during late lactation. Life Sci 2016; 148:241-6. [PMID: 26874026 DOI: 10.1016/j.lfs.2016.02.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 02/06/2016] [Accepted: 02/09/2016] [Indexed: 01/15/2023]
Abstract
AIMS Melanin-concentrating hormone (MCH) is implicated in the control of food intake, body weight regulation and energy homeostasis. Lactation is an important physiological model to study the hypothalamic integration of peripheral sensory signals, such as suckling stimuli and those related to energy balance. MCH can be detected in the medial preoptic area (MPOA), especially around the 19th day of lactation, when this hormone is described as displaying a peak synthesis followed by a decrease after weaning. The physiological significance of this phenomenon is unclear. Therefore, we aimed to investigate hypothalamic changes associated to sensory stimulation by the litter, in special its influence over MCH synthesis. MAIN METHODS Female Wistar rats (n=56) were euthanized everyday from lactation days 15-21, with or without suckling stimulus (WS and NS groups, respectively). MCH and Fos immunoreactivity were evaluated in the MPOA and lateral and incerto-hypothalamic areas (LHA and IHy). KEY FINDINGS Suckling stimulus induced Fos synthesis in all regions studied. An increase on the number of suckling-induced Fos-ir neurons could be detected in the LHA after the 18th day. Conversely, the amount of MCH decreased in the MPOA from days 15-21, independent of suckling stimulation. No colocalization between MCH and Fos could be detected in any region analyzed. SIGNIFICANCE Suckling stimulus is capable of stimulating hypothalamic regions not linked to maternal behavior, possibly to mediate energy balance aspects of lactation. Although dams are hyperphagic before weaning, this behavioral change does not appear to be mediated by MCH.
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Affiliation(s)
- R D Alvisi
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, Brazil
| | - G B Diniz
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - J M Da-Silva
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - J C Bittencourt
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; Center for Neuroscience and Behavior, Institute of Psychology, University of São Paulo, Sao Paulo 05508-030, Brazil
| | - L F Felicio
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, Brazil.
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8
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Bittencourt JC. Anatomical organization of the melanin-concentrating hormone peptide family in the mammalian brain. Gen Comp Endocrinol 2011; 172:185-97. [PMID: 21463631 DOI: 10.1016/j.ygcen.2011.03.028] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 03/23/2011] [Accepted: 03/28/2011] [Indexed: 11/24/2022]
Abstract
More than 20 years ago, melanin-concentrating hormone (MCH) and its peptide family members - neuropeptide EI (NEI) and neuropeptide GE (NGE) - were described in various species, including mammals (rodents, humans, and non-human primates). Since then, most studies have focused on the role of MCH as an orexigenic peptide, as well as on its participation in learning, spatial memory, neuroendocrine control, and sleep. It has been shown that MCH mRNA or the neuropeptide MCH are present in neurons of the prosencephalon, hypothalamus and brainstem. However, most of the neurons containing MCH/NEI are within the incerto-hypothalamic and lateral hypothalamic areas. In addition, the terminals of those neurons are distributed widely throughout the central nervous system. In this review, we will discuss the relationship between those territories and the roles played by MCH/NEI, as well as the importance of MCH receptor 1 in the respective terminal fields. Certain neurochemical features of MCH- and NEI-immunoreactive (MCH-ir and NEI-ir) neurons will also be discussed. The overarching theme is the anatomical organization of an inhibitory neuropeptide colocalized with an inhibitory neurotransmitter in integrative territories of the central nervous system, such as the IHy and LHA. Although these territories have connections to few brain regions, the regions to which they are connected are relevant, being responsible for the organization of motivated behaviors. All available information on this peptidergic system (anatomical, neurochemical, hodological, physiological, pharmacological and behavioral data) suggests that MCH is intimately involved in arousal and the initiation of motivated behaviors.
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Affiliation(s)
- Jackson C Bittencourt
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, SP, Brazil.
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9
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Leinninger GM. Lateral thinking about leptin: a review of leptin action via the lateral hypothalamus. Physiol Behav 2011; 104:572-81. [PMID: 21550356 DOI: 10.1016/j.physbeh.2011.04.060] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 04/19/2011] [Accepted: 04/28/2011] [Indexed: 12/30/2022]
Abstract
The lateral hypothalamic area (LHA) was initially described as a "feeding center" but we are now beginning to understand that the LHA contributes to other aspects of physiology as well. Indeed, the best-characterized neuronal populations of the LHA (which contain melanin-concentrating hormone (MCH) or the hypocretins/orexins (OX)) are not strictly orexigenic, but also have roles in regulation of the autonomic and sympathetic nervous systems as well as in modulating motivated behavior. Leptin is an anorectic hormone that regulates energy homeostasis and the mesolimbic DA system (which transduces the wanting of food, drugs of abuse, and sex) in part, via actions at the LHA. At least three populations of LHA neurons are regulated by leptin: those containing MCH, OX or the long form of the leptin receptor, LepRb. The emerging picture of leptin interaction with these LHA populations suggests that the LHA is not merely regulating feeding, but is a crucial integrator of energy balance and motivated behavior.
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Affiliation(s)
- Gina M Leinninger
- Division of Metabolism, Endocrinology and Diabetes, Department of Medicine, University of Michigan Medical School, 100 Wall Street, Ann Arbor, MI 48105, USA
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10
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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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Gao XB. Electrophysiological effects of MCH on neurons in the hypothalamus. Peptides 2009; 30:2025-30. [PMID: 19463877 PMCID: PMC2782585 DOI: 10.1016/j.peptides.2009.05.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/06/2009] [Accepted: 05/07/2009] [Indexed: 11/21/2022]
Abstract
Melanin concentrating hormone (MCH) has been implicated in many brain functions and behaviors essential to the survival of animals. The hypothalamus is one of the primary targets where MCH-containing nerve fibers and MCH receptors are extensively expressed and its actions in the brain are exerted. Since the identification of MCH receptors as orphan G protein coupled receptors, the cellular effects of MCH have been revealed in many non-neuronal expression systems (including Xenopus oocytes and cell lines), however, the mechanism by which MCH modulates the activity in the neuronal circuitry of the brain is still under investigation. This review summarizes our current knowledge of electrophysiological effects of MCH on neurons in the hypothalamus, particularly in the lateral hypothalamus. Generally, MCH exerts inhibitory effects on neurons in this structure and may serve as a homeostatic regulator in the lateral hypothalamic area. Given the contrast between the limited data on cellular functions of MCH in the hypothalamus versus a fast growing body of evidence on the vital role of MCH in animal behavior, further investigations of the former are warranted.
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Affiliation(s)
- Xiao-Bing Gao
- Department of OB/GYN and Reproductive Science, Yale University School of Medicine, New Haven, CT 06520, USA.
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12
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Baker BI. Biological role of the pars intermedia in lower vertebrates. CIBA FOUNDATION SYMPOSIUM 2008; 81:166-79. [PMID: 6912095 DOI: 10.1002/9780470720646.ch10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The most obvious function of the pars intermedia in lower vertebrates is the secretion of melanocyte-stimulating hormone (MSH) for the purpose of pigmentary control. In some amphibia, elasmobranchs and teleosts, the histological study of the pars intermedia, the radioimmunoassay of pituitary and plasma MSH and the effects of hypophysectomy and of MSH injection suggest that the activity of the pars intermedia is regulated to satisfy the needs of cryptic colour change. MSH secretion is associated with dispersion of melanin granules and with melanogenesis. However, in other teleost species, both the evidence from pituitary cytology and the failure to respond to MSH injection suggest that pigmentary change is not regulated by changes in the plasma titres of MSH. Results discussed here indicate that MSH alone may be inadequate for pigmentary control. Evidence for non-pigmentary functions of the pars intermedia is circumstantial and fragmentary. It is based on cytological observations of altered pars intermedia activity under certain conditions, and on observations of physiological changes that accompany increased melanotropic activity. Such function include effects of plasmas titres of cortisol in teleosts, resistance to adrenaline-induced hyperglycaemia in toads, and effects on neural activity in fish and amphibia. Evidence for pars intermedia involvement in osmoregulation is briefly discussed.
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Carpenter AJ, Hertzog DL. Melanin-concentrating hormone receptor antagonists as potential antiobesity agents. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.12.11.1639] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Amano M, Takahashi A, Yamanome T, Oka Y, Amiya N, Kawauchi H, Yamamori K. Immunocytochemical localization and ontogenic development of alpha-melanocyte-stimulating hormone (alpha-MSH) in the brain of a pleuronectiform fish, barfin flounder. Cell Tissue Res 2005; 320:127-34. [PMID: 15726422 DOI: 10.1007/s00441-004-1058-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Accepted: 11/23/2004] [Indexed: 10/25/2022]
Abstract
Alpha-melanocyte-stimulating hormone (alpha-MSH) is a pituitary hormone derived by post-translational processing from proopiomelanocortin and is involved in background adaptation in teleost fish. It has also been reported to suppress food intake in mammals. Here, we examined the immunocytochemical localization of alpha-MSH in the brain and pituitary of a pleuronectiform fish, the barfin flounder (Verasper moseri), as a first step in unraveling the possible function of alpha-MSH in the brain. The ontogenic development of the alpha-MSH system was also studied. In the pituitary, alpha-MSH-immunoreactive (ir) cells were preferentially detected in the pars intermedia. In the brain, alpha-MSH-ir neuronal somata were located in the nucleus tuberis lateralis of the basal hypothalamus, and alpha-MSH-ir fibers were located mainly in the telencephalon, hypothalamus, and midbrain. Alpha-MSH-ir neuronal somata did not project their axons to the pituitary. The alpha-MSH-ir neurons differed from those immunoreactive to melanin-concentrating hormone. Alpha-MSH cells in the pituitary and alpha-MSH-ir neuronal somata in the brain were first detected 1 day and 5 days after hatching, respectively. The distribution of alpha-MSH-ir cells, neuronal somata, and fibers showed a pattern similar to that in adult fish 30 days after hatching. These results indicate that the functions of alpha-MSH in the brain and pituitary are different and that alpha-MSH plays physiological roles in the early development of the barfin flounder.
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Affiliation(s)
- Masafumi Amano
- School of Fisheries Sciences, Kitasato University, Ofunato, Iwate, 022-0101, Japan.
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Shi Y. Beyond skin color: emerging roles of melanin-concentrating hormone in energy homeostasis and other physiological functions. Peptides 2004; 25:1605-11. [PMID: 15476927 DOI: 10.1016/j.peptides.2004.02.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Accepted: 02/24/2004] [Indexed: 10/26/2022]
Abstract
Melanin-concentrating hormone (MCH) is a cyclic peptide that mediates its effects by the activation of two G-protein-coupled seven transmembrane receptors (MCHR1 and MCHR2) in humans. In contrast to its primary role in regulating skin color in fish, MCH has evolved in mammals to regulate dynamic physiological functions, from food intake and energy expenditure to behavior and emotion. Chronic infusion or transgenic expression of MCH stimulates feeding and increases adipocity, whereas targeted deletion of MCH or its receptor (MCHR1) leads to resistance to diet-induced obesity with increased energy expenditure and thermogenesis. The involvement of MCH in energy homeostasis and in brain activity has also been validated in mice treated with non-peptide antagonists, suggesting that blockade of MCHR1 could provide a viable approach for treatment of obesity and certain neurological disorders. This review focuses on emerging roles of MCH in regulating central and peripheral mechanisms.
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Affiliation(s)
- Yuguang Shi
- Endocrine Research, Lilly Research Laboratories, DC 0545, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
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Gao X, Hsu CK, Heinz LJ, Morin J, Shi Y, Shukla NK, Smiley DL, Xu J, Zhong B, Slieker LJ. Europium-labeled melanin-concentrating hormone analogues: ligands for measuring binding to melanin-concentrating hormone receptors 1 and 2. Anal Biochem 2004; 328:187-95. [PMID: 15113696 DOI: 10.1016/j.ab.2004.01.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2003] [Indexed: 11/16/2022]
Abstract
We investigated the use of Eu3+ chelate-labeled analogues of melanin-concentrating hormone (MCH) as ligands for both human MCH receptors (MCHR1 and MCHR2). The analogues employed were Ala17 MCH, S36057 (Y-ADO-RC*MLGRVFRPC*W, where ADO=8-amino-3,6-dioxyoctanoyl and *=disulfide bond), and R2P (RC*MLGRVFRPC*Y-NH2). The peptides were readily labeled on the alpha-amino residue with the Eu3+ chelate of N1-(p-isothiocyanatobenzyl)-diethylenetriamine-N1,N2,N3,N3-tetraacetic acid and then purified by reverse-phase fast-performance liquid chromatography at neutral pH to maintain Eu3+ chelation. Both labeled Ala17 MCH and S36057 had high affinity for MCHR1 ( Kd = 0.37 and 0.059nM, respectively) while Eu3+ -labeled S36057 and R2P had high affinity for MCHR2 ( Kd = 0.16 and 0.10nM, respectively). Labeled Ala17 MCH had little demonstrable binding affinity for MCHR2. Eu3+ -labeled S36057 and R2P were full agonists at MCHR1 when assessed by measurement of agonist-stimulated GTPgamma(35)S binding. Competition binding experiments with both MCHR isoforms, a series of previously characterized alanine scan MCH analogues, and a recently identified nonpeptide MCHR1-selective antagonist T-226296 confirmed the expected receptor selectivity. These studies further extend the utility of Eu3+ chelate time-resolved fluorescence for the development of high-sensitivity, nonradioactive receptor binding assays and demonstrate the need to select the optimal ligand for labeling.
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Affiliation(s)
- Xiaoying Gao
- Endocrine Discovery Research, Lilly Research Laboratories, Eli Lilly and Co., DC 0545, Indianapolis, IN 46285, USA
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17
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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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18
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Chaffer CL, Morris MJ. The feeding response to melanin-concentrating hormone is attenuated by antagonism of the NPY Y(1)-receptor in the rat. Endocrinology 2002; 143:191-7. [PMID: 11751609 DOI: 10.1210/endo.143.1.8569] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Melanin-concentrating hormone (MCH) and NPY are orexigenic peptides localized in the lateral hypothalamic area and arcuate nucleus, respectively. Although both NPY- and MCH-containing fibers innervate areas of the hypothalamus implicated in feeding, the extent to which the regulation of appetite is dependent on interactions between these peptides is unknown. Daytime feeding responses to 2 nmol MCH, 1 nmol NPY, or vehicle were investigated in male Sprague Dawley rats previously implanted with intracerebroventricular cannulas. The effects of prior administration of the Y(1)-receptor antagonists BIBO 3304 (20 nmol) or GR231118 (5 nmol) on these responses were examined. NPY and MCH stimulated food intake relative to vehicle (4 h intake, 5.9 +/- 0.7 and 3.6 +/- 0.2 g, respectively; P < 0.0001). BIBO 3304 and GR231118 significantly inhibited MCH- induced feeding by 73% (P < 0.01) and 86% (P < 0.01), respectively, at 2 h. Coadministration of NPY and MCH did not increase food intake above that in response to NPY alone; however, prior administration of BIBO 3304 resulted in a less marked inhibition of feeding (P < 0.05, 30 min only). Inhibition of MCH-induced feeding by two structurally different NPY Y(1)-receptor antagonists provides strong evidence that the orexigenic action of MCH involves the Y(1)-receptor.
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Affiliation(s)
- Christine L Chaffer
- Department of Pharmacology, University of Melbourne, Melbourne, Victoria 3010, Australia
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19
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Abstract
Immune-neuroendocrine interactions in fish, as in mammals, have become a focus of considerable interest, with the modulation of immune responses by hormones receiving particular attention. Cortisol, growth hormone (GH), prolactin (PRL), reproductive hormones, melanin-concentrating hormone (MCH) and proopiomelanocortin (POMC)-derived peptides have all been shown to influence immune functions in a number of fish species. This review summarises the known effects of these hormones on the fish immune system, as well as the often complex interactions between different hormones. The possible implications for fish health, with respect to aquaculture and the changes in immunocompetence that take place during different stages in the fish life cycle are also discussed.
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Affiliation(s)
- J Harris
- Faculty of Applied Sciences, University of the West of England, BS16 1QY, Bristol, UK.
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20
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Harris J, Bird DJ. Supernatants from leucocytes treated with melanin-concentrating hormone (MCH) and alpha-melanocyte stimulating hormone (alpha-MSH) have a stimulatory effect on rainbow trout (Oncorhynchus mykiss) phagocytes in vitro. Vet Immunol Immunopathol 2000; 76:117-24. [PMID: 10973690 DOI: 10.1016/s0165-2427(00)00205-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Melanin-concentrating hormone (MCH) and alpha-melanocyte stimulating hormone (alpha-MSH) are widespread vertebrate neuropeptides. In teleost fish the peptides are involved in the hormonal control of skin pigmentation, but they have also been shown to modulate corticosteroid secretion in both fish and mammals. alpha-MSH has additional potent anti-inflammatory actions in mammals and both peptides stimulate leucocyte phagocytosis in rainbow trout in vitro. The effects of these peptides on phagocytosis and the release of immunomodulatory factors by rainbow trout head kidney leucocytes were investigated in vitro. Neither MCH nor alpha-MSH had any effect on the adherence of phagocytes to glass slides or the activity of isolated phagocytes. When added to mixed leucocyte suspensions, however, MCH (50 and 100nM) and alpha-MSH (1 and 10nM) significantly increased the percentage of cells undergoing phagocytosis and MCH (50nM), but not alpha-MSH, stimulated the phagocytic index. In subsequent experiments, isolated phagocytes were exposed to supernatants derived from mixed leucocyte suspensions exposed to MCH (50 and 100nM) and alpha-MSH (1 and 10nM). Supernatants from leucocytes exposed to all doses of the peptides significantly increased the percentage phagocytosis and those from cells stimulated with MCH (100nM) and alpha-MSH (1 and 10nM) increased the phagocytic index of the phagocytes. The results suggest that cells other than phagocytes are required for MCH and alpha-MSH to exert their stimulatory effects on trout phagocytic cells through the release of one or more macrophage-activating factors.
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Affiliation(s)
- J Harris
- Faculty of Applied Sciences, University of the West of England, Bristol, BS16 1QY UK.
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21
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Rossi M, Beak SA, Choi SJ, Small CJ, Morgan DG, Ghatei MA, Smith DM, Bloom SR. Investigation of the feeding effects of melanin concentrating hormone on food intake--action independent of galanin and the melanocortin receptors. Brain Res 1999; 846:164-70. [PMID: 10556632 DOI: 10.1016/s0006-8993(99)02005-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Melanin concentrating hormone (MCH) is recognised as a hypothalamic appetite stimulant. The mechanism of action of MCH is undetermined largely due to lack of identification of hypothalamic MCH receptors. We designed in vivo and in vitro studies to further characterise the feeding effects of MCH in the rat. MCH was injected directly into the paraventricular nucleus (PVN) at the beginning of the light phase. PVN MCH (0.5 microg) produced an increase in 2 h food intake of 272+/-60% vs. saline control (0.7+/-0.2 g), p<0.05. The time course of the effect of intracerebroventricular (i.c.v.) administration of 5 microg MCH on food intake was investigated. An increase in feeding was observed within 15 min from the time of injection and was not sustained beyond half an hour following administration. To investigate a possible interaction with galanin, 5 microg of MCH was injected i.c.v. with or without 10 microg of galanin. The two peptides together increased 1 h feeding above that of either peptide alone, 768+/-62% (compared with the saline group, 0.47+/-0.2 g), p<0.05 vs. 585+/-36%, galanin alone and 317+/-72%, MCH alone. Finally, to investigate if MCH bound to the brain melanocortin receptors, receptor autoradiography was performed on rat brain sections with the stable analogue of alpha MSH, [125I] Nle(4), D-Phe(7)-alphaMSH and unlabeled MCH. MCH did not compete with [125I] Nle(4), D-Phe(7)-alphaMSH binding. Results demonstrate that MCH stimulates feeding via the PVN, has a short onset and duration of action and activates feeding by mechanisms independent to galanin and the melanocortin receptors.
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Affiliation(s)
- M Rossi
- ICSM Endocrine Unit, 6th Floor Commonwealth Bldg., Hammersmith Hospital, DuCane Road, London, UK.
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22
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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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23
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Thorburn AW, Proietto J. Neuropeptides, the hypothalamus and obesity: insights into the central control of body weight. Pathology 1998; 30:229-36. [PMID: 9770185 DOI: 10.1080/00313029800169366] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Body weight tends to remain relatively stable for long periods over an adult's lifespan. Dieting can reduce weight by 5-10%, but in most individuals attempts to lose larger amounts of weight are counteracted by a reduction in energy expenditure and an increase in hunger. The fact that body weight appears to be actively defended in this manner suggests that it is homeostatically regulated at a certain "set-point". Such a mechanism is likely to be centrally controlled by the brain since the hypothalamus can sense the amount of adipose tissue stored in the body and can alter both energy intake and expenditure. Over the past four years a number of major advances have reinforced the critical role the brain may play in controlling body weight, and these have greatly enhanced our understanding of this area. Advances have included the identification of several genetic mutations that cause obesity in animal models, examination of the metabolic consequences of such mutations and the development of mice with genetically engineered altered neuropeptide levels. This review summarises what has been recently discovered about the regulation of body weight by the brain and how this may be disrupted in obesity.
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Affiliation(s)
- A W Thorburn
- Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Victoria, Australia
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24
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Abstract
Melanocortin peptides (adrenocorticotropin (ACTH), alpha-,beta-, and gamma-melanocyte stimulating hormone (MSH), and fragments thereof) derived from proopiomelanocortin (POMC) have a diverse array of biological activities, many of which have yet to be fully elucidated. The recent cloning of a family of five distinct melanocortin receptors through which these peptides act has provided the tools to further our understanding of melanocortin peptide functions. Early work on melanocortin peptides focused on their roles in pigmentation, adrenocortical function, the immune, central and peripheral nervous systems. Although melanocortin peptides have long been known to affect lipolysis, characterisation of the melanocortin receptors has opened up several lines of evidence for important roles in the development of obesity, insulin resistance and type II diabetes. We present here a review of the current evidence for melanocortin peptides playing such a role, and based on this evidence, a model for melanocortin peptides and their receptors in maintaining energy balance.
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Affiliation(s)
- K G Mountjoy
- Research Centre for Developmental Medicine and Biology, Department of Paediatrics, University of Auckland, New Zealand
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25
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adipose Tissue/physiology
- Agouti Signaling Protein
- Animals
- CCAAT-Enhancer-Binding Proteins
- Carboxypeptidase H
- Carboxypeptidases/genetics
- Carboxypeptidases/physiology
- Carrier Proteins/genetics
- Carrier Proteins/physiology
- Cell Differentiation
- DNA-Binding Proteins/physiology
- Feeding Behavior/physiology
- Gene Expression Regulation/physiology
- Homeostasis/physiology
- Hormones/physiology
- Humans
- Hypothalamus/physiopathology
- Insulin Resistance/genetics
- Intercellular Signaling Peptides and Proteins
- Leptin
- Mice
- Mice, Mutant Strains
- Models, Biological
- Neuropeptide Y/physiology
- Nuclear Proteins/physiology
- Obesity/genetics
- Obesity/physiopathology
- Proteins/genetics
- Proteins/physiology
- Receptors, Adrenergic, beta/genetics
- Receptors, Adrenergic, beta-3
- Receptors, Cell Surface
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Leptin
- Sterol Regulatory Element Binding Protein 1
- Transcription Factors/physiology
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Affiliation(s)
- B M Spiegelman
- Dana-Farber Cancer Institute and the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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26
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Qu D, Ludwig DS, Gammeltoft S, Piper M, Pelleymounter MA, Cullen MJ, Mathes WF, Przypek R, Kanarek R, Maratos-Flier E. A role for melanin-concentrating hormone in the central regulation of feeding behaviour. Nature 1996; 380:243-7. [PMID: 8637571 DOI: 10.1038/380243a0] [Citation(s) in RCA: 976] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The hypothalamus plays a central role in the integrated regulation of energy homeostasis and body weight, and a number of hypothalamic neuropeptides, such as neuropeptide Y (ref. 1), galanin, CRH (ref. 3) and GLP-1 (ref. 4), have been implicated in the mediation of these effects. To discover new hypothalmic peptides involved in the regulation of body weight, we used differential display polymerase chain reaction to identify messenger RNAs that are differentially expressed in the hypothalamus of ob/+ compared with ob/ob C57B1/6J mice. We show here that one mRNA that is overexpressed in the hypothalamus of ob/ob mice encodes the neuropeptide melanin-concentrating hormone (MCH). Fasting further increased expression of MCH mRNA in both normal and obese animals. Neurons containing MCH are located in the zona incerta and in the lateral hypothalamus. These areas are involved in regulation of ingestive behaviour, but the role of MCH in mammalian physiology is unknown. To determine whether MCH is involved in the regulation of feeding, we injected MCH into the lateral ventricles of rats and found that their food consumption increased. These findings suggest that MCH participates in the hypothalamic regulation of body weight.
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Affiliation(s)
- D Qu
- Elliott P. Joslin Research Laboratory, Joslin Diabetes Center, Boston, MA, USA
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27
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Abstract
The behavioral effects of alpha-MSH, MCH, and alpha-MSH + MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) (bilateral, 100 ng in 0.5 microliter). Infusion of alpha-MSH into the VMN increased aggressive behavior; in the MPOA it reduced exploration and increased anxiety. In both areas it stimulated sexual behavior. MCH also stimulated sexual behavior in the MPOA and VMN and had an anxiogenic effect in the MPOA. The effect of alpha-MSH on aggression and exploration was antagonized by MCH. When given together, the two peptides were mutually antagonistic on anxiety. This study indicates that MCH has central nervous system effects and may be a partial alpha-MSH agonist.
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Affiliation(s)
- M I Gonzalez
- Department of Obstetrics and Gynaecology, St. George's Hospital Medical School, London, UK
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28
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Suzuki M, Narnaware YK, Baker BI, Levy A. Influence of environmental colour and diurnal phase on MCH gene expression in the trout. J Neuroendocrinol 1995; 7:319-28. [PMID: 7647775 DOI: 10.1111/j.1365-2826.1995.tb00764.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Melanin-concentrating hormone (MCH) gene expression in the brain of rainbow trout, reared and maintained in either pale or black-coloured tanks, was studied using in situ hybridization histochemistry. MCH transcripts were most prevalent in the magnocellular neurones of the nucleus lateralis tuberis (NLT), which project to the pituitary gland. They were also present, although at much lower levels, in dorsally projecting parvocellular neurones, sited more posteriorly above the lateral ventricular recess (LVR). In the NLT the most intense hybridization signal was seen over the pituitary stalk; above the LVR, the most active neurones were located caudally. In both the NLT and above the LVR, MCH hybridization signal was 4-fold stronger in white-reared fish than in black-reared fish. There was also a marked diurnal variation in MCH expression in both sites, with high levels at 16.00 h and lower levels at 04.00 h. The results show that gene activity in both hormonal (NLT) and neuromodulator/neurotransmitter (LVR) MCH neurones is induced by pale environmental colour and that MCH gene activity is subject to pronounced diurnal variation.
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Affiliation(s)
- M Suzuki
- School of Biology and Biochemistry, Bath University, UK
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29
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Drozdz R, Eberle AN. Binding sites for melanin-concentrating hormone (MCH) in brain synaptosomes and membranes from peripheral tissues identified with highly tritiated MCH. J Recept Signal Transduct Res 1995; 15:487-502. [PMID: 8903959 DOI: 10.3109/10799899509045235] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Melanin-concentrating hormone (MCH) is a neuropeptide occurring in the brain of all vertebrate species. In chromatophores of teleost fishes it induces pigment granule aggregation. In mammals, however, its physiological function is not yet clear. Attempts to identify the site(s) of its action by binding analysis failed because radioiodinated MCH with the natural sequence was devoid of biological activity. We have now synthesized an analogue of rat/human MCH, [Pra4,8,12,19]-MCH, containing four L-propargylglycine (Pra) residues in positions 4, 8, 12, and 19 for catalytic tritiation to norvaline ([3H4]Nva) residues, each of which containing four tritium atoms. The resulting [3H]-MCH ([(3H4)Nva4,8,12,19]-MCH) had a specific radioactivity of approx. 12,200 GBq/mmol (330 Ci/mmol) and retained a biological activity of 10% as compared to rat/human MCH when tested in the carp scale assay. A series of qualitative binding studies performed with rat crude membranes from brain and peripheal tissues as well as with rat brain synaptosomes using the [3H]-MCH radioligand provided the first evidence for the presence of MCH receptors in mammalian tissues. The data showed that specific binding is present in the hypothalamus, hippocampus and in the adrenal gland while none was detected in the brain cortex or spleen. Owing to the tendency of [3H]-MCH to non-specific binding to tissue, glass and plastic surfaces, a saturation binding analysis with this radioligand was not possible.
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Affiliation(s)
- R Drozdz
- Laboratory of Endocrinology, Department of Research, University Hospital, Basel, Switzerland
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30
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Abstract
The melanin-concentrating hormone (MCH) is a vertebrate neuropeptide produced in hypothalamic perikarya whose fibers project to most regions of the brain and into the spinal cord. Its role as a neurohypophyseal color-change hormone is peculiar to teleost fish, but recent studies in mammals suggests that MCH itself, and other peptides derived from the same precursor, may participate in multiple functions in the central nervous system, modulating behavior and the perception of sensory information. Recent hybridization studies in mammals have greatly increased our understanding of the response of the MCH system to environmental factors, such as osomotic challenge, lactation, stress, and changes in corticosteroid levels. Further studies in lower vertebrates are needed to highlight the physiologically important functions that have led to the structural conservation of the MCH peptide during vertebrate evolution.
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Affiliation(s)
- B I Baker
- School of Biology and Biochemistry, Bath University, Bath, Avon BA2 7AY, England
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31
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Abstract
The neurohypophysial melanin-concentrating hormone, MCH, plays a role in adaptive colour change in teleost fishes inducing pallor when the fish is placed in pale-coloured surroundings. The present study shows that its plasma concentration, measured in groups of white-adapted fish, is not uniformly high throughout the day but follows a clear diurnal pattern. Over a 24 h cycle, plasma concentrations rise gradually during the morning to reach peak values around the middle of the photophase, after which they decline significantly before night. Lowest concentrations are observed during the dark period. This pattern was observed under a long photoperiod in summer and a short photoperiod in winter. The peak was shifted within a week of changing the onset of either light or dark. When dawn was delayed by 6 h for fish held under short photoperiod conditions, then peak concentrations were attained 6 h precociously. Fish from a long photoperiod placed in constant light showed a pattern of MCH release which approximated to the normal over the first 24 h period but plasma values then became raised and periodicity was no longer discernible. Plasma hormone concentrations were much reduced in trout kept in black coloured tanks in which nocturnal and daytime values differed, but significant differences during the photophase were not demonstrable. The results suggest that an illuminated white background can initiate the early morning release of MCH, and that an endogenous pacemaker underlies the pattern of MCH secretion.
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Affiliation(s)
- V E Lyon
- School of Biological Sciences, Bath University, UK
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32
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Affiliation(s)
- B I Baker
- School of Biological Sciences, Bath University, United Kingdom
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33
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Affiliation(s)
- H Kawauchi
- Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan
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34
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al-Yousuf S, Mizuno N. Electron microscopic identification of axons containing melanin-concentrating hormone in the lamprey, Lampetra fluviatilis L. Neurosci Lett 1991; 128:249-52. [PMID: 1945044 DOI: 10.1016/0304-3940(91)90272-u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Melanin-concentrating hormone-like immunoreactivity (MCH-LI) was examined in the hypothalamo-hypophysial region of the lamprey. At the light microscopic level, MCH-LI neuronal cell bodies were shown with the peroxidase anti-peroxidase method; they were seen in the hypothalamic region close to the third ventricle. MCH-LI axons were observed to run toward the proximal neurosecretory contact region (PNCR) and the most proximal part of the neurohypophysis. Electron microscopic analysis with the immunogold method revealed that presumed secretory granules within axonal profiles showed MCH-LI. MCH-LI axonal profiles were most often seen on or near the basement membrane of connective tissue layer separating the PNCR from the hypophysial pars distalis.
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Affiliation(s)
- S al-Yousuf
- School of Biological Sciences, University of Bath, Claverton Down, U.K
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35
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Baker BI. Melanin-concentrating hormone: a general vertebrate neuropeptide. INTERNATIONAL REVIEW OF CYTOLOGY 1991; 126:1-47. [PMID: 2050497 DOI: 10.1016/s0074-7696(08)60681-6] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- B I Baker
- School of Biological Sciences, University of Bath, Cleverton Down, England
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36
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Affiliation(s)
- D A Powers
- Hopkins Marine Station, Department of Biological Sciences, Stanford University, Pacific Grove, California 93950
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37
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The influence of in vitro sodium and potassium ion ratio on teleost melanosome intracellular motility. Cell Mol Life Sci 1989. [DOI: 10.1007/bf01950170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Takayama Y, Wada C, Kawauchi H, Ono M. Structures of two genes coding for melanin-concentrating hormone of chum salmon. Gene 1989; 80:65-73. [PMID: 2792771 DOI: 10.1016/0378-1119(89)90251-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two MCH genes coding for melanin-concentrating hormone (MCH) were isolated from a chum salmon liver DNA library and characterized. They were shown to be intronless genes with 0.63-kb exons, each of which commonly consisted of an about 80-bp 5'-untranslated region, a region coding for 132 amino acids (aa) MCH precursor protein and an approx. 160-bp 3'-untranslated region. About 20 bp upstream from the putative cap site, sequences were found corresponding to the TATA box. The two genes were 86% identical at the nucleotide sequence level. Sequences homologous to the chum salmon MCH genes were present in the genomes of other fish such as catfish, carp and Chinese grass carp, whereas no highly homologous sequence could be detected in other vertebrate genomes.
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Affiliation(s)
- Y Takayama
- Department of Molecular Biology, School of Medicine, Kitasato University, Kanagawa, Japan
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39
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Bresson JL, Clavequin MC, Fellmann D, Bugnon C. Human hypothalamic neuronal system revealed with a salmon melanin-concentrating hormone (MCH) antiserum. Neurosci Lett 1989; 102:39-43. [PMID: 2779843 DOI: 10.1016/0304-3940(89)90304-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An antiserum raised against synthetic salmon melanin-concentrating hormone (MCH) reveals an extensive neuronal system in the posterior lateral areas of the human hypothalamus. These neurons correspond to those previously described in the rat, which are characterized by expression of MCH-like, alpha-melanotropin-like and human growth hormone-releasing factor (1-37)-like immunoreactivities.
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Affiliation(s)
- J L Bresson
- CNRS URA 561, Laboratoire d'Histologie-Embryologique, Faculté de Médecine, Besançon, France
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40
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Minth CD, Qiu H, Akil H, Watson SJ, Dixon JE. Two precursors of melanin-concentrating hormone: DNA sequence analysis and in situ immunochemical localization. Proc Natl Acad Sci U S A 1989; 86:4292-6. [PMID: 2471200 PMCID: PMC287438 DOI: 10.1073/pnas.86.11.4292] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Two precursors to Chinook salmon (Oncorhynchus tshawytscha) melanin-concentrating hormone, an important factor in teleosts involved in the control of skin pigmentation and stress responsiveness, have been identified from DNA sequence analysis. Both precursors encode proteins of 132 amino acids and they share 107/132 amino acid identities. The biologically active 17-residue peptide is located at the C terminus of both precursors and can be liberated by proteolytic cleavage following two adjacent arginine residues. Additional putative proteolytic processing sites are located within the two precursors. Northern analysis demonstrated an intense hybridization signal of 750 nucleotides in the hypothalamus. Immunocytochemical studies as well as in situ hybridization analyses identify intensely staining cell bodies in the hypothalamus in the area of the lateral tuberal nucleus.
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Affiliation(s)
- C D Minth
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907
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41
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Abstract
Two methods are described for measuring the titres of melanin-concentrating hormone (MCH) in trout plasma. One involves the extraction of MCH from 1-ml plasma onto C18 Sep Pak cartridges, after which the eluted peptide is measured by conventional radioimmunoassay. In the alternative method, antibodies are bound onto immunobeads which are added to 0.5 ml plasma. After incubation for 24 hr, the beads are washed to remove the plasma and are incubated with 125I-labelled MCH; the following day, the labelled beads are separated by centrifugation, washed, and counted. The relative advantages of each method is discussed. Using these two methods, it is shown that the plasma concentration of the hormone is significantly higher in fish from white tanks (greater than 50 pmol/litre) than in fish from black tanks (approximately 10 pmol/litre) or those kept in the dark (approximately 5 pmol/litre). The plasma concentration of MCH changes rapidly when trout are moved from one coloured background to another, indicating its involvement in physiological colour change.
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Affiliation(s)
- M Kishida
- School of Biological Sciences, Bath University, England
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42
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Vallarino M, Andersen AC, Delbende C, Ottonello I, Eberle AN, Vaudry H. Melanin-concentrating hormone (MCH) immunoreactivity in the brain and pituitary of the dogfish Scyliorhinus canicula. Colocalization with alpha-melanocyte-stimulating hormone (alpha-MSH) in hypothalamic neurons. Peptides 1989; 10:375-82. [PMID: 2547205 DOI: 10.1016/0196-9781(89)90046-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The distribution of melanin-concentrating hormone (MCH) in the central nervous system of the dogfish Scyliorhinus canicula was determined by indirect immunofluorescence and peroxidase-anti-peroxidase techniques, using an antiserum raised against synthetic salmon MCH. Three groups of MCH-positive cell bodies were localized in the posterior hypothalamus. The most prominent cell group was detected in the nucleus sacci vasculosi. Scattered MCH-immunoreactive cells were observed in the nucleus tuberculi posterioris and in the nucleus lateralis tuberis. At the pituitary level, the caudal part of the median lobe of the pars distalis contained strongly MCH-positive perikarya. Some of these cells were liquor-contacting-type. Immunoreactive fibers originating from the hypothalamic perikarya projected throughout the dorsal wall of the posterior hypothalamus. Positive fibers were also detected within the thalamus and the central gray of the mesencephalon. The distribution of MCH-containing neurons was compared to that of alpha-MSH-immunoreactive elements using consecutive, 5-micron thick sections. Both MCH- and alpha-MSH-immunoreactive peptides were found in the same neurons of the nucleus sacci vasculosi. These data suggest that MCH and alpha-MSH, two neuropeptides which exert antagonistic activities on skin melanophores, may also act in a coordinate manner in the central nervous system of cartilaginous fish.
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Affiliation(s)
- M Vallarino
- Istituto di Anatomia Comparata, Università Degli Studi di Genova, Italy
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43
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Kawauchi H. Melanin concentrating hormone. II. Structure and biosynthesis of melanin-concentrating hormone. Life Sci 1989; 45:1133-40. [PMID: 2677572 DOI: 10.1016/0024-3205(89)90500-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Melanin-concentrating hormone is a neuropeptide produced in teleost hypothalami and transferred to the neurohypophysis. Salmon MCH was a novel cyclic heptadecapeptide capable of inducing melanin aggregation of integumentary melanophores at picoto nano-molar concentrations in all teleosts tested. The MCH gene is intronless and the exon encodes a 132 amino acid precursor protein, in which the heptadecapeptide of MCH locates at the C-terminal end. Immunohistochemical surveys with anti-salmon MCH antiserum strongly suggest that an MCH-like peptide is present in the hypothalami of higher vertebrates. Biological effects of salmon MCH on other vertebrates are found to be versatile.
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Affiliation(s)
- H Kawauchi
- Laboratory of Molecular Endocrinology, School of Fisheries Sciences, Kitasato University, Iwate, Japan
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44
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Eberle AN, Baker BI, Kishida M, Baumann JB, Girard J. Melanin concentrating hormone. IV. Development of a sensitive solid-phase radioimmunoassay for melanin-concentrating hormone. Life Sci 1989; 45:1149-54. [PMID: 2796601 DOI: 10.1016/0024-3205(89)90502-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A two-step solid-phase radioimmunoassay for melanin-concentrating hormone (MCH) was developed for direct determination of the hormone in plasma samples. To this end, synthetic MCH was coupled to bovine thyreoglobulin and the complex was injected into rabbits. Specific antisera of high titer were obtained which did not crossreact with other hormones. The IgGs were chemically linked to immunobeads, an acrylamide/acrylic acid polymer matrix. In the first step, plasma MCH was immunoextracted by incubation of diluted plasma samples with anti-MCH immunobeads. In the second step, the washed polymer was incubated with radioiodinated MCH tracer for titration of non-occupied sites. This procedure made it possible to determine as little as 4 pg MCH per ml of plasma. Application of the radioimmunoassay to plasma levels of black or white background-adapted trout showed a marked difference in circulating MCH: while trout on a black background contained a mean value of 29 +/- 5.6 pg/ml, animals on a white background had 106 +/- 19 pg/ml. These findings strengthen the hypothesis that MCH is directly involved in the control of color change of teleost fishes. By contrast, there was no detectable salmonid MCH immunoreactivity in rat or human plasma.
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Affiliation(s)
- A N Eberle
- Department of Research, University Hospital, Basel, Switzerland
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45
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Kishida M, Baker BI, Bird DJ. Localisation and identification of melanocyte-stimulating hormones in the fish brain. Gen Comp Endocrinol 1988; 71:229-42. [PMID: 3203871 DOI: 10.1016/0016-6480(88)90251-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The existence of melanocyte-stimulating hormone (MSH) in fish brains was investigated by a range of techniques: radioimmunoassay, HPLC, bioassay, and immunocytochemistry. Immunoreactive alpha MSH (ir alpha MSH) was detected by radioimmunoassay in all regions of carp and trout brains, with the highest concentration in the basal hypothalamus. In trout, ir alpha MSH cell bodies were located by immunocytochemistry only periventricularly, in the medial basal hypothalamus near the third ventricle, whereas in the carp ir alpha MSH staining was seen both in periventricular cells and also in some of the magnocellular neurones in the lateral hypothalamus. When white-adapted fish were transferred to a black tank for 6 days, the melanin-concentrating hormone (MCH) content of the basal hypothalamus of both carp and trout increased 2- and 4.6-fold, respectively, but the alpha MSH content did not change in either species. Analysis by HPLC of pituitary gland, hypothalamic, and optic tectal extracts revealed that the pituitary contains desacetyl, monoacetyl, and diacetyl alpha MSH, although the ratio of these forms differed in the two species. The hypothalamus and optic tectum, however, contained predominantly the desacetyl form of alpha MSH. Bioassays for MSH in the HPLC fractions revealed the existence of presumptive beta MSH in both the pituitary and hypothalamus. An argument is advanced that the periventricular ir alpha MSH neurones are homologous with the proopiomelanocortin cells of the arcuate nucleus in mammals, and that the immunocytochemical alpha MSH-like activity in the MCH neurones may not be authentic alpha MSH.
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Affiliation(s)
- M Kishida
- School of Biological Sciences, Bath University, Claverton Down, England
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46
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Schoofs L, Jegou S, Andersen AC, Tonon MC, Eberle AN, Huybrechts R, De Loof A, Vaudry H. Coexistence of melanin-concentrating hormone and alpha-melanocyte-stimulating hormone immunoreactivities in the central nervous system of the locust, Locusta migratoria. Brain Res 1988; 450:202-8. [PMID: 2841002 DOI: 10.1016/0006-8993(88)91559-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The distribution of melanin concentrating hormone (MCH) in the central nervous system of the locust Locusta migratoria was studied by the indirect immunofluorescence technique, using antibodies against salmon MCH. Most MCH-immunoreactive perikarya were found in the optic lobes at both sides of the brain, dorsally with respect to the lamina ganglionaris. The same neurons also contain alpha-melanocyte-stimulating hormone (alpha-MSH)-like material. In addition, a moderate number of MCH-like neurons, which were devoid of alpha-MSH-immunoreactive substances, was observed in the pars intercerebralis. Bright immunofluorescent fibers were visualized in various regions of the central nervous system of the locust: the optic lobes, the ocelli, the proto-and deuterocerebrum, the subesophageal connectives and the corpora cardiaca. In the ventral nerve cord and the subesophageal ganglion, where alpha-MSH-like cell bodies were encountered, MCH immunoreactive perikarya were absent and immunoreactive fibers were scarce. The coexistence of MCH and alpha-MSH-immunoreactive material within the same specific neurons might indicate an evolutionary relationship of both peptides.
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Affiliation(s)
- L Schoofs
- Zoological Institute of the University, Leuven, Belgium
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47
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Batten TF, Baker BI. Melanin-concentrating hormone (MCH) immunoreactive hypophysial neurosecretory system in the teleost Poecilia latipinna: light and electron microscopic study. Gen Comp Endocrinol 1988; 70:193-205. [PMID: 3384304 DOI: 10.1016/0016-6480(88)90140-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurons containing immunoreactivity for melanin-concentrating hormone (MCH) were located in the brain of the teleost Poecilia latipinna by light microscopic (peroxidase antiperoxidase) and electron microscopic (immunogold) methods. Neuronal cell bodies were found in the tuberal hypothalamus, mostly within the nucleus lateralis tuberis, pars lateralis, containing MCH-immunoreactive granules up to 150 nm in diameter. From here bundles of immunoreactive fibers could be traced through the preoptic area as far forward as the olfactory bulb, and through the posterior hypothalamus up into the pretectal thalamus and midbrain. The main projection was, however, to the neurohypophysis, where MCH fibers were observed to form contacts with pituicytes, basement membranes around blood vessels, and the endocrine cells of the pars intermedia. Occasionally MCH-immunoreactive terminals were also seen near the corticotrophs of the rostral pars distalis. These results support the hypothesis that MCH may act as a systemic hormone, a central neurotransmitter, and a modulator of pituitary function.
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Affiliation(s)
- T F Batten
- Department of Cardiovascular Studies, The University, Leeds, United Kingdom
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48
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Sherbrooke WC, Hadley ME. Exploring the evolutionary history of melanin-concentrating and melanin-stimulating hormone receptors on melanophores: neopterygian (holostean) and chondrostean fishes. PIGMENT CELL RESEARCH 1988; 1:344-9. [PMID: 3237601 DOI: 10.1111/j.1600-0749.1988.tb00130.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The occurrence of melanin-concentrating hormone (MCH) receptors on integumental melanophores was found to extend back in the evolutionary line of ray-finned bony fishes (Actinopterygii) to the group ancestral to modern teleosts, the Holostei. The two species of holosteans studied, Amia calva and Lepisosteus platyrhincus, exhibited changes of melanophore index (melanosome aggregation), indicating responses to MCH and to melatonin but no response to norepinephrine (NE). Polyodon spathula, a species of chondrostean (an older group of bony fishes ancestral to holosteans), failed to respond to MCH, to melatonin, or to NE. Nevertheless, Polyodon skin darkened (melanosome dispersion) in response to melanocyte-stimulating hormone (MSH). The preliminary implication of these observations is that the mechanism of physiological color change involving MCH and its melanophore receptors evolved near the end of the Paleozoic or during the early Mesozoic, just before or early in the evolution of neopterygian (holostean and teleostean) fishes.
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Affiliation(s)
- W C Sherbrooke
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson 85721
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49
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Powell KA, Baker BI. Structural studies of nerve terminals containing melanin-concentrating hormone in the eel, Anguilla anguilla. Cell Tissue Res 1988; 251:433-9. [PMID: 3345554 DOI: 10.1007/bf00215852] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Eels were adapted to black- or white-coloured backgrounds and the pituitary glands were prepared for light and electron microscopy. Immunocytochemical staining was used to study the distribution of the neurohypophysial melanin-concentrating hormone in the neurointermediate lobe. The hormone was located in small, elliptical, electron-opaque neurosecretory granules, measuring approximately 120 x 90 nm. The neurones terminated on blood vessels in the centre of the neurohypophysis and on the basement membrane separating neural and intermediate lobe tissues. The results of both light and electron immunocytochemistry and of radioimmunoassay are consistent with a higher rate of hormone release from eels adapted to white backgrounds than from those adapted to black backgrounds. In addition to this, when fish that had been adapted to white tanks were transferred to black tanks, there was an accumulation of irMCH in the gland and an increased numerical density of secretory granules at nerve terminals. These results reinforce the proposal that MCH is released during adaptation to a white background, to cause melanin concentration and to inhibit MSH release, and that its release is halted in black-adapted fish.
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Affiliation(s)
- K A Powell
- Electron Optics Centre, School of Materials Science, University of Bath, United Kingdom
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50
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Fellmann D, Bugnon C, Risold PY. Unrelated peptide immunoreactivities coexist in neurons of the rat lateral dorsal hypothalamus: human growth hormone-releasing factor1-37-, salmon melanin-concentrating hormone- and alpha-melanotropin-like substances. Neurosci Lett 1987; 74:275-80. [PMID: 2436110 DOI: 10.1016/0304-3940(87)90309-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antisera raised against 3 unrelated synthetic neuropeptides - salmon melanin-concentrating hormone, human growth hormone-releasing factor1-37, and alpha-melanotropin - stained the same extensive neuron population in lateral and dorsal areas of the posterior hypothalamus. Controls for specificity have shown that these 3 antisera bind 3 different epitopes. Differences in intracellular staining patterns suggest that these epitopes could be borne by distinct peptides.
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