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Benítez-King G, Argueta J, Miranda-Riestra A, Muñoz-Delgado J, Estrada-Reyes R. Interaction of the Melatonin/Ca 2+-CaM Complex with Calmodulin Kinase II: Physiological Importance. Mol Pharmacol 2024; 106:3-12. [PMID: 38811168 DOI: 10.1124/molpharm.123.000812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 04/04/2024] [Accepted: 04/15/2024] [Indexed: 05/31/2024] Open
Abstract
Melatonin N-acetyl-5-methoxytriptamine is an ancient molecule which synchronizes the internal biologic activity with the environmental photoperiod. It is synthesized by the pineal gland during the night and released to the general circulation, where it reaches nanomolar concentrations. The indolamine acts through melatonin receptors and binds to different proteins such as calmodulin: a phylogenetically conserved protein which is the main transductor of the calcium signaling. In this review, we will describe evidence supporting that melatonin binds to calmodulin in presence of calcium, and we discuss the effects of this indolamine on the activity of calmodulin kinase II as an inhibitor and as stimulator of calmodulin-dependent protein kinase II activity. We also provide a literature review supporting the relevance of melatonin binding to calmodulin in the regulation of circadian rhythms in unicellular organisms, as well as in neuronal development in mammals as an ancient, conserved mechanism. Finally, we highlight the importance of antioxidant effects of melatonin on calmodulin preservation. SIGNIFICANCE STATEMENT: This review compiled evidence supporting that melatonin binds to calmodulin. We discuss the dual effect of melatonin on the activity of calmodulin kinase II, the possible mechanisms involved, and the relevance on regulation of circadian rhythms and neurodevelopment. Finally, we describe evidence supporting that the binding of melatonin to calmodulin hydrophobic pockets may prevent the oxidation of methionine species with a shielding effect that preserves the functionality of calmodulin.
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Affiliation(s)
- Gloria Benítez-King
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (G.B.-K., J.A., A.M.-R.); Laboratorio de Cronoecología y Etología Humana, Departamento de Etología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (J.M.-D.); and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (R.E-R.)
| | - Jesús Argueta
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (G.B.-K., J.A., A.M.-R.); Laboratorio de Cronoecología y Etología Humana, Departamento de Etología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (J.M.-D.); and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (R.E-R.)
| | - Armida Miranda-Riestra
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (G.B.-K., J.A., A.M.-R.); Laboratorio de Cronoecología y Etología Humana, Departamento de Etología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (J.M.-D.); and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (R.E-R.)
| | - Jairo Muñoz-Delgado
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (G.B.-K., J.A., A.M.-R.); Laboratorio de Cronoecología y Etología Humana, Departamento de Etología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (J.M.-D.); and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (R.E-R.)
| | - Rosa Estrada-Reyes
- Laboratorio de Neurofarmacología, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (G.B.-K., J.A., A.M.-R.); Laboratorio de Cronoecología y Etología Humana, Departamento de Etología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (J.M.-D.); and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México City, México (R.E-R.)
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Roman-Ramos H, Prieto-da-Silva ÁRB, Dellê H, Floriano RS, Dias L, Hyslop S, Schezaro-Ramos R, Servent D, Mourier G, de Oliveira JL, Lemes DE, Costa-Lotufo LV, Oliveira JS, Menezes MC, Markus RP, Ho PL. The Cloning and Characterization of a Three-Finger Toxin Homolog (NXH8) from the Coralsnake Micrurus corallinus That Interacts with Skeletal Muscle Nicotinic Acetylcholine Receptors. Toxins (Basel) 2024; 16:164. [PMID: 38668589 PMCID: PMC11054780 DOI: 10.3390/toxins16040164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/04/2024] [Accepted: 03/20/2024] [Indexed: 04/29/2024] Open
Abstract
Coralsnakes (Micrurus spp.) are the only elapids found throughout the Americas. They are recognized for their highly neurotoxic venom, which is comprised of a wide variety of toxins, including the stable, low-mass toxins known as three-finger toxins (3FTx). Due to difficulties in venom extraction and availability, research on coralsnake venoms is still very limited when compared to that of other Elapidae snakes like cobras, kraits, and mambas. In this study, two previously described 3FTx from the venom of M. corallinus, NXH1 (3SOC1_MICCO), and NXH8 (3NO48_MICCO) were characterized. Using in silico, in vitro, and ex vivo experiments, the biological activities of these toxins were predicted and evaluated. The results showed that only NXH8 was capable of binding to skeletal muscle cells and modulating the activity of nAChRs in nerve-diaphragm preparations. These effects were antagonized by anti-rNXH8 or antielapidic sera. Sequence analysis revealed that the NXH1 toxin possesses eight cysteine residues and four disulfide bonds, while the NXH8 toxin has a primary structure similar to that of non-conventional 3FTx, with an additional disulfide bond on the first loop. These findings add more information related to the structural diversity present within the 3FTx class, while expanding our understanding of the mechanisms of the toxicity of this coralsnake venom and opening new perspectives for developing more effective therapeutic interventions.
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Affiliation(s)
- Henrique Roman-Ramos
- Laboratório de Biotecnologia, Programa de Pós-Graduação em Medicina, Universidade Nove de Julho (UNINOVE), São Paulo 01504-001, SP, Brazil; (H.D.); (J.L.d.O.); (D.E.L.)
| | | | - Humberto Dellê
- Laboratório de Biotecnologia, Programa de Pós-Graduação em Medicina, Universidade Nove de Julho (UNINOVE), São Paulo 01504-001, SP, Brazil; (H.D.); (J.L.d.O.); (D.E.L.)
| | - Rafael S. Floriano
- Laboratório de Toxinologia e Estudos Cardiovasculares, Universidade do Oeste Paulista (UNOESTE), Presidente Prudente 19067-175, SP, Brazil;
| | - Lourdes Dias
- Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-887, SP, Brazil; (L.D.); (S.H.); (R.S.-R.)
| | - Stephen Hyslop
- Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-887, SP, Brazil; (L.D.); (S.H.); (R.S.-R.)
| | - Raphael Schezaro-Ramos
- Departamento de Farmacologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-887, SP, Brazil; (L.D.); (S.H.); (R.S.-R.)
| | - Denis Servent
- Service d’Ingénierie Moléculaire pour la Santé (SIMoS), Département Médicaments et Technologies pour la Santé, Université Paris Saclay, Commissariat à l’énergie Atomique et aux Énergies Alternatives (CEA), F-91191 Gif sur Yvette, France; (D.S.); (G.M.)
| | - Gilles Mourier
- Service d’Ingénierie Moléculaire pour la Santé (SIMoS), Département Médicaments et Technologies pour la Santé, Université Paris Saclay, Commissariat à l’énergie Atomique et aux Énergies Alternatives (CEA), F-91191 Gif sur Yvette, France; (D.S.); (G.M.)
| | - Jéssica Lopes de Oliveira
- Laboratório de Biotecnologia, Programa de Pós-Graduação em Medicina, Universidade Nove de Julho (UNINOVE), São Paulo 01504-001, SP, Brazil; (H.D.); (J.L.d.O.); (D.E.L.)
| | - Douglas Edgard Lemes
- Laboratório de Biotecnologia, Programa de Pós-Graduação em Medicina, Universidade Nove de Julho (UNINOVE), São Paulo 01504-001, SP, Brazil; (H.D.); (J.L.d.O.); (D.E.L.)
| | - Letícia V. Costa-Lotufo
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo (USP), São Paulo 05508-000, SP, Brazil;
| | - Jane S. Oliveira
- Centro de Biotecnologia, Instituto Butantan, São Paulo 05503-900, SP, Brazil;
| | | | - Regina P. Markus
- Laboratório de Cronofarmacologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo 05508-090, SP, Brazil;
| | - Paulo Lee Ho
- Centro Bioindustrial, Instituto Butantan, São Paulo 05503-900, SP, Brazil;
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Samizadeh MA, Fallah H, Toomarisahzabi M, Rezaei F, Rahimi-Danesh M, Akhondzadeh S, Vaseghi S. Parkinson's Disease: A Narrative Review on Potential Molecular Mechanisms of Sleep Disturbances, REM Behavior Disorder, and Melatonin. Brain Sci 2023; 13:914. [PMID: 37371392 DOI: 10.3390/brainsci13060914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/01/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative diseases. There is a wide range of sleep disturbances in patients with PD, such as insomnia and rapid eye movement (REM) sleep behavior disorder (or REM behavior disorder (RBD)). RBD is a sleep disorder in which a patient acts out his/her dreams and includes abnormal behaviors during the REM phase of sleep. On the other hand, melatonin is the principal hormone that is secreted by the pineal gland and significantly modulates the circadian clock and mood state. Furthermore, melatonin has a wide range of regulatory effects and is a safe treatment for sleep disturbances such as RBD in PD. However, the molecular mechanisms of melatonin involved in the treatment or control of RBD are unknown. In this study, we reviewed the pathophysiology of PD and sleep disturbances, including RBD. We also discussed the potential molecular mechanisms of melatonin involved in its therapeutic effect. It was concluded that disruption of crucial neurotransmitter systems that mediate sleep, including norepinephrine, serotonin, dopamine, and GABA, and important neurotransmitter systems that mediate the REM phase, including acetylcholine, serotonin, and norepinephrine, are significantly involved in the induction of sleep disturbances, including RBD in PD. It was also concluded that accumulation of α-synuclein in sleep-related brain regions can disrupt sleep processes and the circadian rhythm. We suggested that new treatment strategies for sleep disturbances in PD may focus on the modulation of α-synuclein aggregation or expression.
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Affiliation(s)
- Mohammad-Ali Samizadeh
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj 3365166571, Iran
| | - Hamed Fallah
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran 1417935840, Iran
| | - Mohadeseh Toomarisahzabi
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj 3365166571, Iran
| | - Fereshteh Rezaei
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj 3365166571, Iran
| | - Mehrsa Rahimi-Danesh
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj 3365166571, Iran
| | - Shahin Akhondzadeh
- Psychiatric Research Center, Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, Tehran 13337159140, Iran
| | - Salar Vaseghi
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj 3365166571, Iran
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Eno CC, Graakjaer J, Svaneby D, Nizon M, Kianmahd J, Signer R, Martinez-Agosto JA, Quintero-Rivera F. 14q32.11 microdeletion including CALM1, TTC7B, PSMC1, and RPS6KA5: A new potential cause of developmental and language delay in three unrelated patients. Am J Med Genet A 2021; 185:1519-1524. [PMID: 33634591 DOI: 10.1002/ajmg.a.62117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/14/2020] [Accepted: 01/23/2021] [Indexed: 12/18/2022]
Abstract
Three unrelated patients with similar microdeletions of chromosome 14q32.11 with shared phenotypes including language and developmental delay, and four overlapping genes -CALM1, TTC7B, PSMC1, and RPS6KA5 have been presented. All four genes are expressed in the brain and have haploinsufficiency scores, which reflect low tolerance to loss of function variation. An insight on the genes in the overlapping region, which may influence the resulting phenotype has been provided. Given the three patients' similar phenotypes and lack of normal variation in this region, it was suggested that this microdeletion may be associated with developmental and language delay.
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Affiliation(s)
- Celeste C Eno
- Department of Academic Pathology, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jesper Graakjaer
- Department of Clinical Genetics, Lillebaelt Hospital, Vejle, Denmark
| | - Dea Svaneby
- Department of Clinical Genetics, Lillebaelt Hospital, Vejle, Denmark
| | - Mathilde Nizon
- Department of Medical Genetics, CHU Nantes, Nantes, France
| | - Jessica Kianmahd
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Rebecca Signer
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Julian A Martinez-Agosto
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Fabiola Quintero-Rivera
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, USA
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Khan S, Khurana M, Vyas P, Vohora D. The role of melatonin and its analogues in epilepsy. Rev Neurosci 2020; 32:/j/revneuro.ahead-of-print/revneuro-2019-0088/revneuro-2019-0088.xml. [PMID: 32950966 DOI: 10.1515/revneuro-2019-0088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/01/2020] [Indexed: 12/31/2022]
Abstract
Extensive research has gone into proposing a promising link between melatonin administration and attenuation of epileptic activity, the majority of which suggest its propensity as an antiseizure with antioxidant and neuroprotective properties. In the past few years, a number of studies highlighting the association of the melatonergic ligands with epilepsy have also emerged. In this context, our review is based on discussing the recent studies and various mechanisms of action that the said category of drugs exhibit in the context of being therapeutically viable antiseizure drugs. Our search revealed several articles on the four major drugs i.e. melatonin, agomelatine, ramelteon and piromelatine along with other melatonergic agonists like tasimelteon and TIK-301. Our review is suggestive of antiseizure effects of both melatonin and its analogues; however, extensive research work is still required to study their implications in the treatment of persons with epilepsy. Further evaluation of melatonergic signaling pathways and mechanisms may prove to be helpful in the near future and might prove to be a significant advance in the field of epileptology.
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Affiliation(s)
- Sumaira Khan
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Mallika Khurana
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Preeti Vyas
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Divya Vohora
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
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The regulatory role of melatonin in skeletal muscle. J Muscle Res Cell Motil 2020; 41:191-198. [PMID: 32157560 DOI: 10.1007/s10974-020-09578-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/22/2020] [Accepted: 03/02/2020] [Indexed: 12/14/2022]
Abstract
Melatonin (N-acetyl-5-methoxy-tryptamine) is an effective antioxidant and free radical scavenger, that has important biological effects in multiple cell types and species. Melatonin research in muscle has recently gained attention, mainly focused on its role in cells or tissue repair and regeneration after injury, due to its powerful biological functions, including its antioxidant, anti-inflammation, anti-tumor and anti-cancer, circadian rhythm, and anti-apoptotic effects. However, the effect of melatonin in regulating muscle development has not been systematically summarized. In this review, we outline the latest research on the involvement of melatonin in the regulation of muscle development and regeneration in order to better understand its underlying molecular mechanisms and potential applications.
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Nogueira RC, Sampaio LDFS. Eye and heart morphogenesis are dependent on melatonin signaling in chick embryos. ACTA ACUST UNITED AC 2017; 220:3826-3835. [PMID: 28839011 DOI: 10.1242/jeb.159848] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/18/2017] [Indexed: 12/15/2022]
Abstract
Calmodulin is vital for chick embryos morphogenesis in the incubation time 48-66 h when the rudimentary C-shaped heart attains an S-shaped pattern and the optic vesicles develop into optic cups. Melatonin is in the extraembryonic yolk sac of the avian egg; melatonin binds calmodulin. The aim of this study was to investigate the function of melatonin in the formation of the chick embryo optic cups and S-shaped heart, by pharmacological methods and immunoassays. Mel1a melatonin receptor immunofluorescence was distributed in the optic cups and rudimentary hearts. We separated embryonated chicken eggs at 48 h of incubation into basal, control and drug-treated groups, with treatment applied in the egg air sac. At 66 h of incubation, embryos were excised from the eggs and analyzed. Embryos from the basal, control (distilled water), melatonin and 6-chloromelatonin (melatonin receptor agonist) groups had regular optic cups and an S-shaped heart, while those from the calmidazolium (calmodulin inhibitor) group did not. Embryos from the luzindole (melatonin receptor antagonist) and prazosin (Mel1c melatonin receptor antagonist) groups did not have regular optic cups. Embryos from the 4-P-PDOT (Mel1b melatonin receptor antagonist) group did not have an S-shaped heart. Previous application of the melatonin, 6-chloromelatonin or forskolin (adenylate cyclase enhancer) prevented the abnormal appearance of chick embryos from the calmidazolium, luzindole, prazosin and 4-P-PDOT groups. However, 6-chloromelatonin and forskolin only partially prevented the development of defective eye cups in embryos from the calmidazolium group. The results suggested that melatonin modulates chick embryo morphogenesis via calmodulin and membrane receptors.
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Affiliation(s)
- Renato C Nogueira
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará. Av. Augusto Corrêa 1, CEP: 66075-110 Belém, PA, Brazil
| | - Lucia de Fatima S Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará. Av. Augusto Corrêa 1, CEP: 66075-110 Belém, PA, Brazil
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Luo L, Xi C, Xu T, Zhang G, Qun E, Zhang W. Muscarinic receptor mediated signaling pathways in hepatocytes from CCL4 - induced liver fibrotic rat. Eur J Pharmacol 2017; 807:109-116. [DOI: 10.1016/j.ejphar.2017.03.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/17/2017] [Accepted: 03/21/2017] [Indexed: 12/21/2022]
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Sayadi MA, Achour O, Ezzaher A, Hellara I, Omezzine A, Douki W, Bousslama A, Gaha L, Najjar MF. CT genotype of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is protector factor of major depressive disorder in the Tunisian population: a case control study. Ann Gen Psychiatry 2016; 15:18. [PMID: 27478487 PMCID: PMC4967526 DOI: 10.1186/s12991-016-0103-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 06/29/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Major depressive disorder (MDD) is a common psychiatric disorder with considerable mortality. Death from unnatural causes, largely suicidal or quasi-suicidal, has a particularly high risk for the functional disorders, especially depression and schizophrenia. One of the prospective risk factors for this disease is hyperhomocysteinemia and folate deficiency. The methylenetetrahydrofolate reductase (MTHFR) gene encodes for a 5-methylenetetrahydrofolate reductase involved in folate metabolism and neurotransmitter synthesis. The aim of this research is to study the association between the C677T polymorphism of MTHFR gene and depression in Tunisian population, to explore their relationship with clinical and therapeutic characteristics of this disease. And it may lead to discover a novel marker to identify a patient with a higher risk of development of depressive disorder to be. This marker can be used for better therapeutic management and prevent disease installation. METHODS Our study included 208 depressive patients, 187 controls aged between 44.1 ± 13.5 and 38.9 ± 13.2 years, respectively. MTHFR gene polymorphisms were determined by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). RESULTS No significant difference was detected in the distribution of the genotype frequencies of MTHFR C677T polymorphisms (χ (2) = 5.443, df = 2, p = 0.066) between patients and controls. But when we study the risk of these genotypes, CT genotype is significantly more frequent in controls compared to patients, it may be a protection from depression (OR = 0.655, CI 95 % = 0.432-0.995, p = 0.047, OR* = 0.638, CI 95 %* = 0.415-0.983, p* = 0.04, before and after adjustment). Women, TT Genotype can increase four times the risk to be depressive. Addictive behavior seems to be associated with CT genotype and there was no significant association between clinical and therapeutic characteristics and this polymorphism. CONCLUSION This paper is the first study to prove that CT genotype of MTHFR C677T polymorphism may protect from depression and TT genotype seems to be associated with women's depression. Further studies are required with other polymorphisms and biochemical factors that must be investigated to clarify the implication of MTHFR C677T polymorphism in the pathophysiology of depression.
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Affiliation(s)
- Mohamed Amine Sayadi
- Laboratory of Biochemistry-Toxicology, Monastir University Hospital, Monastir, Tunisia ; Research Laboratory "Vulnerability to Psychotic disorders LR 05 ES 10", Department of Psychiatry, Monastir University Hospital, Monastir, Tunisia
| | - Ons Achour
- LR 12 SP 11, Biochemistry Department, Sahloul Sousse University Hospital, Sousse, Tunisia
| | - Asma Ezzaher
- Laboratory of Biochemistry-Toxicology, Monastir University Hospital, Monastir, Tunisia ; Research Laboratory "Vulnerability to Psychotic disorders LR 05 ES 10", Department of Psychiatry, Monastir University Hospital, Monastir, Tunisia
| | - Ilham Hellara
- Laboratory of Biochemistry-Toxicology, Monastir University Hospital, Monastir, Tunisia
| | - Asma Omezzine
- LR 12 SP 11, Biochemistry Department, Sahloul Sousse University Hospital, Sousse, Tunisia
| | - Wahiba Douki
- Laboratory of Biochemistry-Toxicology, Monastir University Hospital, Monastir, Tunisia
| | - Ali Bousslama
- LR 12 SP 11, Biochemistry Department, Sahloul Sousse University Hospital, Sousse, Tunisia
| | - Lotfi Gaha
- Research Laboratory "Vulnerability to Psychotic disorders LR 05 ES 10", Department of Psychiatry, Monastir University Hospital, Monastir, Tunisia
| | - Mohamed Fadhel Najjar
- Laboratory of Biochemistry-Toxicology, Monastir University Hospital, Monastir, Tunisia
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Melatonin therapy for REM sleep behavior disorder: a critical review of evidence. Sleep Med 2014; 16:19-26. [PMID: 25454845 DOI: 10.1016/j.sleep.2014.09.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 11/23/2022]
Abstract
Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia associated with dream enactment often involving violent or potentially injurious behaviors during REM sleep that is strongly associated with synucleinopathy neurodegeneration. Clonazepam has long been suggested as the first-line treatment option for RBD. However, evidence supporting melatonin therapy is expanding. Melatonin appears to be beneficial for the management of RBD with reductions in clinical behavioral outcomes and decrease in muscle tonicity during REM sleep. Melatonin also has a favorable safety and tolerability profile over clonazepam with limited potential for drug-drug interactions, an important consideration especially in elderly individuals with RBD receiving polypharmacy. Prospective clinical trials are necessary to establish the evidence basis for melatonin and clonazepam as RBD therapies.
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Cardinali DP, Vidal MF, Vigo DE. Agomelatine: Its Role in the Management of Major Depressive Disorder. ACTA ACUST UNITED AC 2012. [DOI: 10.4137/cmpsy.s7989] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Circadian rhythm abnormalities, as shown by sleep/wake cycle disturbances, constitute one the most prevalent signs of depressive illness; advances or delays in the circadian phase are documented in patients with major depressive disorder (MDD), bipolar disorder, and seasonal affective disorder (SAD). The disturbances in the amplitude and phase of rhythm in melatonin secretion that occur in patients with depression resemble those seen in chronobiological disorders, thus suggesting a link between disturbed melatonin secretion and depressed mood. Based on this, agomelatine, the first MT1/MT2 melatonergic agonist displaying also 5-HT2C serotonergic antagonism, has been introduced as an antidepressant. Agomelatine has been shown to be effective in several animal models of depression and anxiety and it has beneficial effects in patients with MDD, bipolar disorder, or SAD. Among agomelatine's characteristics are a rapid onset of action and a pronounced effectiveness for correcting circadian rhythm abnormalities and improving the sleep/wake cycle. Agomelatine also improves the 3 functional dimensions of depression—emotional, cognitive, and social—thus aiding in the full recovery of patients to a normal life.
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Affiliation(s)
- Daniel P. Cardinali
- Department of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, Buenos Aires, Argentina
| | - María F. Vidal
- Department of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, Buenos Aires, Argentina
| | - Daniel E. Vigo
- Department of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, Buenos Aires, Argentina
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Aguiar CCT, Almeida AB, Araújo PVP, Vasconcelos GS, Chaves EMC, do Vale OC, Macêdo DS, de Sousa FCF, Viana GSDB, Vasconcelos SMM. Anticonvulsant effects of agomelatine in mice. Epilepsy Behav 2012; 24:324-8. [PMID: 22658946 DOI: 10.1016/j.yebeh.2012.04.134] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 03/31/2012] [Accepted: 04/27/2012] [Indexed: 11/25/2022]
Abstract
Agomelatine is a potent MT1 and MT2 melatonin receptor agonist and a 5-HT2C serotonin receptor antagonist. We analyzed whether agomelatine has anticonvulsant properties. The anticonvulsant activity of agomelatine (25, 50 or 75 mg/kg, i.p.) was evaluated in mouse models of pentylenetetrazole (PTZ-85 mg/kg, i.p.), pilocarpine (400mg/kg, i.p.), picrotoxin (7 mg/kg, i.p.), strychnine (75 mg/kg, i.p.) or electroshock-induced convulsions. In the PTZ-induced seizure model, agomelatine (at 25 or 50mg/kg) showed a significant increase in latency to convulsion, and agomelatine (at 50 or 75 mg/kg) also increased significantly time until death. In the pilocarpine-induced seizure model, only agomelatine in high doses (75 mg/kg) showed a significant increase in latency to convulsions and in time until death. In the strychnine-, electroshock- and picrotoxin-induced seizure models, agomelatine caused no significant alterations in latency to convulsions and in time until death when compared to controls. Our results suggest that agomelatine has anticonvulsant activity shown in PTZ- or pilocarpine-induced seizure models.
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Affiliation(s)
- Carlos Clayton Torres Aguiar
- School of Medicine, University of Fortaleza (UNIFOR)/RENORBIO, Rua Desembargador Floriano Benevides Magalhães, 221 3° Andar-60811-690, Fortaleza, Ceará, Brazil
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Markus RP, Silva CLM, Franco DG, Barbosa EM, Ferreira ZS. Is modulation of nicotinic acetylcholine receptors by melatonin relevant for therapy with cholinergic drugs? Pharmacol Ther 2010; 126:251-62. [PMID: 20398699 DOI: 10.1016/j.pharmthera.2010.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 02/24/2010] [Indexed: 12/31/2022]
Abstract
Melatonin, the darkness hormone, synchronizes several physiological functions to light/dark cycle. Besides the awake/sleep cycle that is intuitively linked to day/night, daily variations in memory acquisition and innate or acquired immune responses are some of the major activities linked to melatonin rhythm. The daily variation of these complex processes is due to changes in specific mechanisms. In the last years we focused on the influence of melatonin on the expression and function of nicotinic acetylcholine receptors (nAChRs). Melatonin, either "in vivo" or "in vitro", increases, in a selective manner, the efficiency of alpha-bungarotoxin (alpha-BTX)-sensitive nAChRs. Melatonin's effect on receptors located in rat sympathetic nerve terminals, cerebellum, skeletal muscle and chick retina, was tested. We observed that melatonin is essential for the development of alpha-BTX-sensitive nAChRs, and important for receptor maintenance in aging models. Taking into account that both melatonin and alpha-7 nAChRs (one of the subtypes sensitive to alpha-BTX) are involved in the development of Alzheimer's disease, here we discuss the possibility of a therapeutic strategy focused on both melatonin replacement and its potential association with cholinergic drugs.
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Affiliation(s)
- Regina P Markus
- Laboratory of Chronopharmacology, Department of Physiology, Institute of Bioscience, Universidade de São Paulo, Brazil.
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Pedrosa AMDC, Weinlich R, Mognol GP, Robbs BK, Viola JPDB, Campa A, Amarante-Mendes GP. Melatonin protects CD4+ T cells from activation-induced cell death by blocking NFAT-mediated CD95 ligand upregulation. THE JOURNAL OF IMMUNOLOGY 2010; 184:3487-94. [PMID: 20181888 DOI: 10.4049/jimmunol.0902961] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Over the past 20 y, the hormone melatonin was found to be produced in extrapineal sites, including cells of the immune system. Despite the increasing data regarding the biological effects of melatonin on the regulation of the immune system, the effect of this molecule on T cell survival remains largely unknown. Activation-induced cell death plays a critical role in the maintenance of the homeostasis of the immune system by eliminating self-reactive or chronically stimulated T cells. Because activated T cells not only synthesize melatonin but also respond to it, we investigated whether melatonin could modulate activation-induced cell death. We found that melatonin protects human and murine CD4(+) T cells from apoptosis by inhibiting CD95 ligand mRNA and protein upregulation in response to TCR/CD3 stimulation. This inhibition is a result of the interference with calmodulin/calcineurin activation of NFAT that prevents the translocation of NFAT to the nucleus. Accordingly, melatonin has no effect on T cells transfected with a constitutively active form of NFAT capable of migrating to the nucleus and transactivating target genes in the absence of calcineurin activity. Our results revealed a novel biochemical pathway that regulates the expression of CD95 ligand and potentially other downstream targets of NFAT activation.
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Affiliation(s)
- Alziana Moreno da Cunha Pedrosa
- Departamento de Análises Clínica e Toxicológica, Faculdade de Ciências Farmacêuticas, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo Brazil
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15
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Fatima Sobral Sampaio L, Markus RP. Melatonin and the time window for the expression of the α8 nicotinic acetylcholine receptor in the membrane of chick retinal cells in culture. Int J Dev Neurosci 2010; 28:245-9. [DOI: 10.1016/j.ijdevneu.2010.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Revised: 01/11/2010] [Accepted: 01/28/2010] [Indexed: 01/15/2023] Open
Affiliation(s)
- Lucia Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do ParáBelémPABrazil
- Laboratório de CronofarmacologiaDepartamento de FisiologiaInstituto de Biociências, Universidade de São PauloSão PauloSPBrazil
| | - Regina Pekelmann Markus
- Laboratório de CronofarmacologiaDepartamento de FisiologiaInstituto de Biociências, Universidade de São PauloSão PauloSPBrazil
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Sampaio LDFS. An unexpected effect of 5-MCA-NAT in chick retinal development. Int J Dev Neurosci 2009; 27:511-5. [PMID: 19596433 DOI: 10.1016/j.ijdevneu.2009.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/22/2009] [Accepted: 07/01/2009] [Indexed: 10/20/2022] Open
Abstract
Luzindole is an unselective antagonist of the melatonin receptors and melatonin's other binding sites, although some exceptions have been observed in chick retinal neurodevelopment, where this unselective antagonist does not block melatonin's inhibitory effect on the adenylate cyclase enzyme, probably due to the presence of some other melatonin receptor(s) or binding site(s). The present study investigated the modulation of cyclic adenosine 3'-5'-monophosphate (cAMP) levels via MT3 melatonin-binding sites, located within the QR2 (dihydronicotinamide riboside: quinone oxidoreductase 2) enzyme, by observing the response to luzindole. Embryonic and post-hatch retinas, incubated with a selective agonist for the MT3 melatonin-binding site 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT, 10 or 100 nM), had an increase in cAMP accumulation relative to control retinas. Luzindole (5microM) inhibited the 5-MCA-NAT stimulatory effect at all ages tested. The agonist 5-MCA-NAT enhanced the melatonin inhibitory effect on cAMP levels stimulated by forskolin (5microM), but not the stimulatory forskolin effect. The results suggest that MT3 melatonin-binding sites are present in embryonic and post-hatch chick retinas and that luzindole more selectively blocks the 5-MCA-NAT effect on cAMP accumulation than it blocks the melatonin inhibitory effect via G protein-coupled receptors in chick retinal neurodevelopment.
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Affiliation(s)
- Lucia de Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa, 1, CEP: 66075-110 Belém, PA, Brazil.
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Couto-Moraes R, Palermo-Neto J, Markus RP. The immune-pineal axis: stress as a modulator of pineal gland function. Ann N Y Acad Sci 2009; 1153:193-202. [PMID: 19236342 DOI: 10.1111/j.1749-6632.2008.03978.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The temporal organization of mammals presents a daily adjustment to the environmental light/dark cycle. The environmental light detected by the retina adjusts the central clock in the suprachiasmatic nuclei, which innervate the pineal gland through a polysynaptic pathway. During the night, this gland produces and releases the nocturnal hormone melatonin, which circulates throughout the whole body and adjusts several bodily functions according to the existence and duration of darkness. We have previously shown that during the time frame of an inflammatory response, pro-inflammatory cytokines, such as tumor necrosis factor-alpha, inhibit while anti-inflammatory mediators, such as glucocorticoids, enhance the synthesis of melatonin, interfering in the daily adjustment of the light/dark cycle. Therefore, injury disconnects the organism from environmental cycling, while recovery restores the light/dark information to the whole organism. Here, we extend these observations by evaluating the effect of a mild restraint stress, which did not induce macroscopic gastric lesions. After 2 h of restraint, there was an increase in circulating corticosterone, indicating activation of the hypothalamus-pituitary-adrenal (HPA) axis. In parallel, an increase in melatonin production was observed. Taking into account the data obtained with models of inflammation and stress, we reinforce the hypothesis that the activity of the pineal gland is modulated by the state of the immune system and the HPA axis, implicating the darkness hormone melatonin as a modulator of defense responses.
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Affiliation(s)
- Renato Couto-Moraes
- Laboratory of Chronopharmacology, Department of Physiology, Institute of Bioscience, Universidade de São Paulo, Sao Paulo, Brazil
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18
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Sampaio LDFS. Melatonin inhibitory effect on cAMP accumulation in the chick retina development. Int J Dev Neurosci 2008; 26:277-82. [PMID: 18343081 DOI: 10.1016/j.ijdevneu.2008.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 01/31/2008] [Accepted: 02/01/2008] [Indexed: 10/22/2022] Open
Abstract
During vertebrate neurodevelopment, neuritogenesis and synaptogenesis are modulated by intracellular cAMP rises. Melatonin, which is implicated in neuronal differentiation, mainly inhibits this pathway. Here, an investigation about the profile of this effect during the vertebrate neurodevelopment is reported. In the embryonic chick retinas at days 8, 12, 14, 16 and at 2 days post-hatched (E8, E12, E14, E16 and PH), those control embryonic retinas incubated only with the phosphodiesterase inhibitor at days corresponding to commencement of neuronal differentiation (E8, E12) and PH, presented cAMP levels inhibited by melatonin. While the cAMP accumulation stimulated by forskolin was inhibited in the embryonic retinas at all testing days. Neither the unselective antagonist N-acetyl-2-benziltryptamine (luzindole) nor the selective Mel(1b) antagonist 4-phenyl-2-propionamidotetralin (4-P-PDOT) blocked the melatonin concentration-dependent inhibitory effect on cAMP accumulation in the retinas initiating differentiation (E7-E9), suggesting a tight binding between melatonin and their receptors. However, 4-P-PDOT competitively reverted the melatonin effect on cAMP stimulated by forskolin during synaptogenesis stages. Together, the melatonin effect on cAMP levels in chick retina, which is mainly through melatonin receptors, is depending on the developmental period observed, probably taking part in the mechanisms surrounding the melatonin action on neuronal differentiation.
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Affiliation(s)
- Lucia de Fatima Sobral Sampaio
- Laboratório de Bioquímica do Desenvolvimento do Sistema Nervoso, Instituto de Ciências Biológicas, Universidade Federal do Pará, 1 Belém, PA, Brazil.
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19
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Abstract
There is limited data regarding the effects of melatonin on the activity of neuronal acetylcholine receptors (nAChRs) themselves. This study analyzes the effects of low concentrations of melatonin on nicotine-evoked currents from cerebellar granule neurons (CGNs) in culture. Using electrophysiological and Ca(2+)-imaging techniques, it was found a subset of rat CGNs to which nicotine application elicited both intracellular Ca(2+) transients and inward whole-cell currents. These responses were mediated by heteromeric nAChRs, as assessed by their sensitivity to nicotine and time constant of current decay. Preincubating the cells with low melatonin concentrations (down to 1 pm) significantly reduced the current amplitude in a dose-dependent manner, without affecting the receptor's apparent affinity and voltage-dependency, nor the current's rise and decay time course. The inhibitory effect of melatonin was significantly reduced by luzindole, a competitive antagonist of both MT(1) and MT(2) melatonin receptors. In conclusion, melatonin inhibits nicotinic currents through non-alpha7 heteromeric nAChRs expressed by CGNs in culture, an effect that appears to be at least partially mediated by melatonin membrane receptors. Direct modulation of nicotinic receptors is accomplished at doses that are likely to be physiologically relevant, thus providing a mechanism through which melatonin circadian rhythmic levels could modulate cholinergic activity.
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Affiliation(s)
- Pedro Lax
- Departamento de Fisiología, Genética y Microbiología, División de Fisiología, Universidad de Alicante, Campus de San Vicente, Alicante, Spain.
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Silva CLM, Tamura EK, Macedo SMD, Cecon E, Bueno-Alves L, Farsky SHP, Ferreira ZS, Markus RP. Melatonin inhibits nitric oxide production by microvascular endothelial cells in vivo and in vitro. Br J Pharmacol 2007; 151:195-205. [PMID: 17375079 PMCID: PMC2013957 DOI: 10.1038/sj.bjp.0707225] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE We have previously shown that melatonin inhibits bradykinin-induced NO production by endothelial cells in vitro. The purpose of this investigation was to extend this observation to an in vivo condition and to explore the mechanism of action of melatonin. EXPERIMENTAL APPROACH RT-PCR assays were performed with rat cultured endothelial cells. The putative effect of melatonin upon arteriolar tone was investigated by intravital microscopy while NO production by endothelial cells in vitro was assayed by fluorimetry, and intracellular Ca(2+) measurements were assayed by confocal microscopy. KEY RESULTS No expression of the mRNA for the melatonin synthesizing enzymes, arylalkylamine N-acetyltransferase and hydroxyindole-O-methyltransferase, or for the melatonin MT(2) receptor was detected in microvascular endothelial cells. Melatonin fully inhibited L-NAME-sensitive bradykinin-induced vasodilation and also inhibited NO production induced by histamine, carbachol and 2-methylthio ATP, but did not inhibit NO production induced by ATP or alpha, beta-methylene ATP. None of its inhibitory effects was prevented by the melatonin receptor antagonist, luzindole. In nominally Ca(2+)-free solution, melatonin reduced intracellular Ca(2+) mobilization induced by bradykinin (40%) and 2-methylthio ATP (62%) but not Ca(2+) mobilization induced by ATP. CONCLUSIONS AND IMPLICATIONS We have confirmed that melatonin inhibited NO production both in vivo and in vitro. In addition, the melatonin effect was selective for some G protein-coupled receptors and most probably reflects an inhibition of Ca(2+) mobilization from intracellular stores.
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Affiliation(s)
- C L M Silva
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
| | - E K Tamura
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
| | - S M D Macedo
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo São Paulo, Brazil
| | - E Cecon
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
| | - L Bueno-Alves
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
| | - S H P Farsky
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo São Paulo, Brazil
| | - Z S Ferreira
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
| | - R P Markus
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo São Paulo, Brazil
- Author for correspondence:
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Abstract
Endothelial cell function is a major player on the regulation of both vascular tonus and permeability. Activation of nitric oxide synthase (NOS) by bradykinin is one physiological pathway for the well-known vascular relaxation mediated by endothelial-derived nitric oxide (NO). In this study we investigated if melatonin, which is known to modulate endothelial cell function and NO production in other tissues, is able to impair bradykinin-induced NO production in vitro. Rat microvascular endothelial cells were incubated with fluorescent dyes to detect either NO or Ca2+. In addition, cGMP levels were measured by enzyme immunoassay. We found that while bradykinin (1-100 nm) increased both cytosolic Ca2+ and NO production, melatonin (1 nm) abolished this NO production but not cytosolic Ca2+ elevation. N-acetylserotonin (0.1 and 1 nm) had the same effect, while the selective agonist for MT3 receptors (5-MCA-NAT, 1 nm) had no effect. Moreover, nonselective and MT2-selective antagonists did not alter the effect of melatonin, suggesting that it is not mediated by MT melatonin receptors. A possible direct inhibition of calmodulin was also discarded as melatonin did not mimic the effect of calmidazolium on cytosolic Ca2+. Melatonin also abolished cGMP production induced by 1 microm bradykinin, indicating that the NO downstream effect is impaired. Thus, here we show that melatonin reduces NO production induced by bradykinin by a mechanism upstream to the interaction of Ca2+ -calmodulin with NOS. Moreover, this effect might be the basis of the diurnal variation in endothelial cell function.
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Affiliation(s)
- Eduardo K Tamura
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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