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Felder-Schmittbuhl MP, Hicks D, Ribelayga CP, Tosini G. Melatonin in the mammalian retina: Synthesis, mechanisms of action and neuroprotection. J Pineal Res 2024; 76:e12951. [PMID: 38572848 DOI: 10.1111/jpi.12951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/09/2024] [Accepted: 03/19/2024] [Indexed: 04/05/2024]
Abstract
Melatonin is an important player in the regulation of many physiological functions within the body and in the retina. Melatonin synthesis in the retina primarily occurs during the night and its levels are low during the day. Retinal melatonin is primarily synthesized by the photoreceptors, but whether the synthesis occurs in the rods and/or cones is still unclear. Melatonin exerts its influence by binding to G protein-coupled receptors named melatonin receptor type 1 (MT1) and type 2 (MT2). MT1 and MT2 receptors activate a wide variety of signaling pathways and both receptors are present in the vertebrate photoreceptors where they may form MT1/MT2 heteromers (MT1/2h). Studies in rodents have shown that melatonin signaling plays an important role in the regulation of retinal dopamine levels, rod/cone coupling as well as the photopic and scotopic electroretinogram. In addition, melatonin may play an important role in protecting photoreceptors from oxidative stress and can protect photoreceptors from apoptosis. Critically, melatonin signaling is involved in the modulation of photoreceptor viability during aging and other studies have implicated melatonin in the pathogenesis of age-related macular degeneration. Hence melatonin may represent a useful tool in the fight to protect photoreceptors-and other retinal cells-against degeneration due to aging or diseases.
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Affiliation(s)
- Marie Paule Felder-Schmittbuhl
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Université de Strasbourg, Strasbourg, France
| | - David Hicks
- Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives (UPR 3212), Université de Strasbourg, Strasbourg, France
| | - Christophe P Ribelayga
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, Texas, USA
| | - Gianluca Tosini
- Department of Pharmacology & Toxicology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA
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2
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Rusciano D, Russo C. The Therapeutic Trip of Melatonin Eye Drops: From the Ocular Surface to the Retina. Pharmaceuticals (Basel) 2024; 17:441. [PMID: 38675402 PMCID: PMC11054783 DOI: 10.3390/ph17040441] [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: 03/04/2024] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Melatonin is a ubiquitous molecule found in living organisms, ranging from bacteria to plants and mammals. It possesses various properties, partly due to its robust antioxidant nature and partly owed to its specific interaction with melatonin receptors present in almost all tissues. Melatonin regulates different physiological functions and contributes to the homeostasis of the entire organism. In the human eye, a small amount of melatonin is also present, produced by cells in the anterior segment and the posterior pole, including the retina. In the eye, melatonin may provide antioxidant protection along with regulating physiological functions of ocular tissues, including intraocular pressure (IOP). Therefore, it is conceivable that the exogenous topical administration of sufficiently high amounts of melatonin to the eye could be beneficial in several instances: for the treatment of eye pathologies like glaucoma, due to the IOP-lowering and neuroprotection effects of melatonin; for the prevention of other dysfunctions, such as dry eye and refractive defects (cataract and myopia) mainly due to its antioxidant properties; for diabetic retinopathy due to its metabolic influence and neuroprotective effects; for macular degeneration due to the antioxidant and neuroprotective properties; and for uveitis, mostly owing to anti-inflammatory and immunomodulatory properties. This paper reviews the scientific evidence supporting the use of melatonin in different ocular districts. Moreover, it provides data suggesting that the topical administration of melatonin as eye drops is a real possibility, utilizing nanotechnological formulations that could improve its solubility and permeation through the eye. This way, its distribution and concentration in different ocular tissues may support its pleiotropic therapeutic effects.
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Affiliation(s)
- Dario Rusciano
- Fidia Research Centre, c/o University of Catania, Via Santa Sofia 89, 95123 Catania, Italy
| | - Cristina Russo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 89, 95123 Catania, Italy;
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3
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Kvetnoy I, Ivanov D, Mironova E, Evsyukova I, Nasyrov R, Kvetnaia T, Polyakova V. Melatonin as the Cornerstone of Neuroimmunoendocrinology. Int J Mol Sci 2022; 23:ijms23031835. [PMID: 35163757 PMCID: PMC8836571 DOI: 10.3390/ijms23031835] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 11/23/2022] Open
Abstract
Much attention has been recently drawn to studying melatonin – a hormone whose synthesis was first found in the epiphysis (pineal gland). This interest can be due to discovering the role of melatonin in numerous physiological processes. It was the discovery of melatonin synthesis in endocrine organs (pineal gland), neural structures (Purkinje cells in the cerebellum, retinal photoreceptors), and immunocompetent cells (T lymphocytes, NK cells, mast cells) that triggered the evolution of new approaches to the unifield signal regulation of homeostasis, which, at the turn of the 21st century, lead to the creation of a new integral biomedical discipline — neuroimmunoendocrinology. While numerous hormones have been verified over the last decade outside the “classical” locations of their formation, melatonin occupies an exclusive position with regard to the diversity of locations where it is synthesized and secreted. This review provides an overview and discussion of the major data regarding the role of melatonin in various physiological and pathological processes, which affords grounds for considering melatonin as the “cornerstone” on which neuroimmunoendocrinology has been built as an integral concept of homeostasis regulation.
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Affiliation(s)
- Igor Kvetnoy
- Center of Molecular Biomedicine, Saint-Petersburg Research Institute of Phthisiopulmonology, 191036 Saint-Petersburg, Russia;
- Department of Physiology and Department of Pathology, Saint-Petersburg State University, 199034 Saint-Petersburg, Russia
| | - Dmitry Ivanov
- Department of Pathology, Saint-Petersburg State Pediatric Medical University, 194100 Saint-Petersburg, Russia; (D.I.); (R.N.); (V.P.)
| | - Ekaterina Mironova
- Center of Molecular Biomedicine, Saint-Petersburg Research Institute of Phthisiopulmonology, 191036 Saint-Petersburg, Russia;
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint-Petersburg, Russia;
- Correspondence:
| | - Inna Evsyukova
- Department of Perinatal Pathology, Ott Research Institute of Obstetrics, Gynecology and Reproductology, 199034 Saint-Petersburg, Russia;
| | - Ruslan Nasyrov
- Department of Pathology, Saint-Petersburg State Pediatric Medical University, 194100 Saint-Petersburg, Russia; (D.I.); (R.N.); (V.P.)
| | - Tatiana Kvetnaia
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint-Petersburg, Russia;
| | - Victoria Polyakova
- Department of Pathology, Saint-Petersburg State Pediatric Medical University, 194100 Saint-Petersburg, Russia; (D.I.); (R.N.); (V.P.)
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4
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Tam BB, Siu AW, Lam AF, Lee EY. Effects of vitamin E and pinoline on retinal lipid peroxidation. Clin Exp Optom 2021; 87:171-4. [PMID: 15186208 DOI: 10.1111/j.1444-0938.2004.tb03170.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 03/15/2004] [Accepted: 03/26/2004] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Pinoline is a pineal indoleamine naturally found in the retina. This study compared the effects of pinoline and vitamin E on the copper (I)-induced retinal lipid peroxidation (LPO). METHODS Porcine retinal homogenates were mixed with 120 micro M copper (I) solution. The mixtures were co-incubated with various concentrations of pinoline or trolox (water-soluble vitamin E analogue) at 37 degrees Centigrade for 60 minutes. The amounts of malondialdehyde (MDA) and protein were assayed to quantify the LPO. RESULTS Copper (I) ions significantly increased the MDA concentration in the retinal homogenates (p < 0.0007). Both pinoline and trolox significantly suppressed MDA in a dose-dependent manner (p < 0.0001) and their effects were significantly different (p = 0.004). The concentrations that inhibited 50 per cent of LPO were 0.24 mM and 0.68 mM for pinoline and trolox, respectively. DISCUSSION Pinoline suppressed the LPO at a potency of 2.8 times compared with trolox. The results support an anti-oxidative role for pinoline in the retina. Further study is required to characterise the pharmacological potency of pinoline in vivo.
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Affiliation(s)
- Benny B Tam
- Laboratory of Experimental Optometry, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
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Bonmati-Carrion MA, Tomas-Loba A. Melatonin and Cancer: A Polyhedral Network Where the Source Matters. Antioxidants (Basel) 2021; 10:antiox10020210. [PMID: 33535472 PMCID: PMC7912767 DOI: 10.3390/antiox10020210] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022] Open
Abstract
Melatonin is one of the most phylogenetically conserved signals in biology. Although its original function was probably related to its antioxidant capacity, this indoleamine has been “adopted” by multicellular organisms as the “darkness signal” when secreted in a circadian manner and is acutely suppressed by light at night by the pineal gland. However, melatonin is also produced by other tissues, which constitute its extrapineal sources. Apart from its undisputed chronobiotic function, melatonin exerts antioxidant, immunomodulatory, pro-apoptotic, antiproliferative, and anti-angiogenic effects, with all these properties making it a powerful antitumor agent. Indeed, this activity has been demonstrated to be mediated by interfering with various cancer hallmarks, and different epidemiological studies have also linked light at night (melatonin suppression) with a higher incidence of different types of cancer. In 2007, the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption, where melatonin plays a central role. Our aim is to review, from a global perspective, the role of melatonin both from pineal and extrapineal origin, as well as their possible interplay, as an intrinsic factor in the incidence, development, and progression of cancer. Particular emphasis will be placed not only on those mechanisms related to melatonin’s antioxidant nature but also on the recently described novel roles of melatonin in microbiota and epigenetic regulation.
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Affiliation(s)
- Maria-Angeles Bonmati-Carrion
- Chronobiology Laboratory, Department of Physiology, IMIB-Arrixaca, University of Murcia, 30100 Murcia, Spain
- Ciber Fragilidad y Envejecimiento Saludable, 28090 Madrid, Spain
- Correspondence: (M.-A.B.-C.); (A.T.-L.)
| | - Antonia Tomas-Loba
- Circadian Rhythm and Cancer Laboratory, Department of Physiology, IMIB-Arrixaca, University of Murcia, 30120 Murcia, Spain
- Correspondence: (M.-A.B.-C.); (A.T.-L.)
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Fasciani I, Petragnano F, Aloisi G, Marampon F, Rossi M, Coppolino MF, Rossi R, Longoni B, Scarselli M, Maggio R. A New Threat to Dopamine Neurons: The Downside of Artificial Light. Neuroscience 2020; 432:216-228. [PMID: 32142863 DOI: 10.1016/j.neuroscience.2020.02.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/17/2022]
Abstract
Growing awareness of adverse impacts of artificial light on human health has led to recognize light pollution as a significant global environmental issue. Despite, a large number of studies in rodent and monkey models of Parkinson's disease have reported that near infrared light has neuroprotective effects on dopaminergic neurons, recent findings have shown that prolonged exposure of rodents and birds to fluorescent artificial light results in an increase of neuromelanin granules in substantia nigra and loss of dopaminergic neurons. The observed detrimental effect seems to be dependent on a direct effect of light on the substantia nigra rather than a secondary effect of the alterations of circadian rhythms. Moreover, inferences from animal models to human studies have shown a positive correlation between the prevalence of Parkinson's disease and light pollution. The present article discusses experimental evidence supporting a potentially deleterious impact of light on dopaminergic neurons and highlights the mechanisms whereby light might damage neuronal tissue. Moreover, it analyses epidemiological evidence that suggests light pollution to be an environmental risk factor for Parkinson's disease.
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Affiliation(s)
- Irene Fasciani
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Francesco Petragnano
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Gabriella Aloisi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Francesco Marampon
- Department of Radiotherapy, Policlinico Umberto I, Sapienza University of Rome, Rome, Italy
| | - Mario Rossi
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Maria Francesca Coppolino
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Rodolfo Rossi
- Ph D Programme in Neuroscience, University Tor Vergata, Rome, Italy
| | - Biancamaria Longoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Marco Scarselli
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Roberto Maggio
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
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Tsai D, Chen H, Leu H, Chen S, Hsu N, Huang C, Chen J, Lin S, Chou P. The association between clinically diagnosed insomnia and age-related macular degeneration: a population-based cohort study. Acta Ophthalmol 2020; 98:e238-e244. [PMID: 31496121 DOI: 10.1111/aos.14238] [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: 04/05/2019] [Accepted: 08/09/2019] [Indexed: 12/16/2022]
Abstract
PURPOSE The decreased level of melatonin, the substance involved in the control of the sleep-wake cycle, has been reported among the patients with age-related macular degeneration (AMD). However, knowledge about the relationship between sleep disturbance and AMD is still limited. This longitudinal case-control study aims to investigate the risk of incident AMD among the patients with clinically diagnosed insomnia using the Taiwan National Health Insurance Research Database. METHODS The insomnia cohort (n = 15 465) consisted of newly diagnosed insomnia cases aged ≥55 years between 2000 and 2009. Subjects without insomnia, matched for age, gender and enrolment time, were randomly sampled as the control cohort (n = 92 790). Cox proportional hazard regressions were performed to calculate the hazard ratios (HR) of incident AMD for the two cohorts after adjusting for potential confounders. RESULTS Of the 108 255 sampled subjects, 2094 (1.9%) were diagnosed with AMD, including 214 (0.2%) with neovascular AMD, during a mean follow-up period of 5.1 ± 2.8 years. Insomnia patients were more likely to have subsequent AMD than those without insomnia (2.5% versus 1.8%, p < 0.001). Further, the incidence of exudative AMD was also higher in the insomnia cohort than the control cohort (0.3% versus 0.2%, p = 0.002). The adjusted HR was 1.33 (95% confidence interval [CI], 1.18-1.48, p < 0.001) for AMD and 1.67 (95% CI, 1.20-2.33, p = 0.002) for exudative AMD. CONCLUSIONS Clinically diagnosed insomnia is an independent indicator for the increased risk of subsequent AMD development.
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Affiliation(s)
- Der‐Chong Tsai
- Department of Ophthalmology National Yang‐Ming University Hospital Yilan Taiwan
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Community Medicine Research Center & Institute of Public Health National Yang‐Ming University Taipei Taiwan
| | - Hsi‐Chung Chen
- Community Medicine Research Center & Institute of Public Health National Yang‐Ming University Taipei Taiwan
- Department of Psychiatry & Center of Sleep Disorders National Taiwan University Hospital Taipei Taiwan
| | - Hsin‐Bang Leu
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Cardiovascular Research Center National Yang‐Ming University Taipei Taiwan
- Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan
- Healthcare and Management Center Taipei Veterans General Hospital Taipei Taiwan
| | - Shih‐Jen Chen
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Department of Ophthalmology Taipei Veterans General Hospital Taipei Taiwan
| | - Nai‐Wei Hsu
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Community Medicine Research Center & Institute of Public Health National Yang‐Ming University Taipei Taiwan
- Department of Internal Medicine National Yang‐Ming University Hospital Yilan Taiwan
- Public Health Bureau Yilan County Yilan Taiwan
| | - Chin‐Chou Huang
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Cardiovascular Research Center National Yang‐Ming University Taipei Taiwan
- Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan
- Institute of Pharmacology National Yang‐Ming University Taipei Taiwan
- Department of Medical Education Taipei Veterans General Hospital Taipei Taiwan
| | - Jaw‐Wen Chen
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Cardiovascular Research Center National Yang‐Ming University Taipei Taiwan
- Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan
- Institute of Pharmacology National Yang‐Ming University Taipei Taiwan
- Department of Medical Research Taipei Veterans General Hospital Taipei Taiwan
| | - Shing‐Jong Lin
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Cardiovascular Research Center National Yang‐Ming University Taipei Taiwan
- Division of Cardiology Department of Medicine Taipei Veterans General Hospital Taipei Taiwan
- Healthcare and Management Center Taipei Veterans General Hospital Taipei Taiwan
- Institute of Pharmacology National Yang‐Ming University Taipei Taiwan
| | - Pesus Chou
- National Yang‐Ming University School of Medicine Taipei Taiwan
- Community Medicine Research Center & Institute of Public Health National Yang‐Ming University Taipei Taiwan
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Li C, Tian Y, Yao A, Zha X, Zhang J, Tao Y. Intravitreal Delivery of Melatonin Is Protective Against the Photoreceptor Loss in Mice: A Potential Therapeutic Strategy for Degenerative Retinopathy. Front Pharmacol 2020; 10:1633. [PMID: 32116667 PMCID: PMC7028754 DOI: 10.3389/fphar.2019.01633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/13/2019] [Indexed: 12/12/2022] Open
Abstract
Melatonin is a circadian hormone with potent cytoprotective effects. Retinitis pigmentosa (RP) comprises a heterogeneous group of inherent retinopathies that characterized by the photoreceptor death in bilateral eyes. The N-methyl-N-nitrosourea (MNU) administered mouse is a type of chemically induced RP model with rapid progressive rate. We intend to study the melatonin mediated effects on the MNU administered mice. Melatonin was delivered into the vitreous body of the MNU administered mice. Subsequently, the melatonin treated mice were subjected to histological analysis, optokinetic behavior tests, spectral-domain optical coherence tomography (SD-OCT), and electroretinogram (ERG) examination. Multi-electrodes array (MEA) was used to analyze the status of visual signal transmission within retinal circuits. Biochemical analysis was performed to quantify the expression levels of antioxidative enzymes, oxidative stress markers, and apoptotic factors in the retinas. The intravitreal injection of melatonin ameliorated effectively the MNU induced photoreceptor degeneration. Melatonin therapy mitigated the spontaneous firing response, and preserved the basic configurations of visual signal pathway in MNU administered mice. MEA is effective to evaluate the pharmacological effects on retina. Of note, the cone photoreceptors in degenerative retinas were rescued efficiently by melatonin therapy. Melatonin afforded these protective effects by modulating the apoptotic cascades and alleviating the oxidative stress. These findings suggest that melatonin could act as an alternative treatment for degenerative retinopathy. Melatonin might be used in combination with other therapeutic approaches to alleviate the photoreceptor loss and preserve the visual function of RP patients.
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Affiliation(s)
- Chong Li
- Department of Neurosurgery, PLA General Hospital, Beijing, China
| | - Yi Tian
- Department of Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Anhui Yao
- Department of Neurosurgery, PLA General Hospital, Beijing, China
| | - Xiaobing Zha
- Department of Rehabilitation, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianbin Zhang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi'an, China
| | - Ye Tao
- Department of Ophthalmology, Henan Provincial People’s Hospital, Zhengzhou University, People’s Hospital, Zhengzhou, China
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Betti L, Palego L, Demontis GC, Miraglia F, Giannaccini G. Hydroxyindole- O-methyltransferase (HIOMT) activity in the retina of melatonin-proficient mice. Heliyon 2019; 5:e02417. [PMID: 31687544 PMCID: PMC6819757 DOI: 10.1016/j.heliyon.2019.e02417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 07/19/2019] [Accepted: 09/02/2019] [Indexed: 01/02/2023] Open
Abstract
Numerous pieces of evidence support the expression by the mammalian retina of Hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4), the enzyme directly responsible for the biosynthesis of the pineal chronobiotic hormone melatonin (MLT). However, conflicting results obtained so far by enzyme-kinetic and immune-detection techniques still make HIOMT presence and relevance in the eye a matter of debate. This work aimed at evaluating unambiguously HIOMT activity in the mouse retina, a valuable model for studying the effects of MLT variations on ocular pathophysiology. Since laboratory mouse strains can bear genetic polymorphisms yielding defective enzymes of MLT biosynthesis, retinas and control pineal glands used in this study were obtained in a MLT-proficient crossing of A/J mice, the A/J/C57BL/10 strain. To improve the radiochemical reference assay, we tested different homogenization procedures coupled with HPLC detection. Concomitantly, we quantified MLT, and its precursor N-acetyl-serotonin (NAS) by HPLC coupled to electrochemical detection in retinas isolated from either light- or dark-adapted mice. Results showed that the standard radio-chemical assay was successful for pineal HIOMT only, whereas specific homogenization buffers and HPLC were required to detect retinal activity, presumably due to interfering methyl-transferases inhibited by NAS. Under present conditions, retinal HIOMT Vmax accounted for by ≈ 40 fmol/h/mg protein, 2.6-hundreds-fold lower than the pineal counterpart, displaying equivalent KMs (≈10 μM). Moreover, NAS and MLT rapidly decreased in light-exposed isolated retinas, corroborating light-sensitive in-situ MLT formation. Conclusively, we measured mouse retinal HIOMT kinetics under basal conditions, a useful result to elucidate the regulatory patterns, the possible impact on eye health, and therapeutic approaches related to this enzyme.
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Affiliation(s)
- Laura Betti
- Department of Pharmacy, Via Bonanno 6, University of Pisa, 56126 Pisa, Italy
- Corresponding author.
| | - Lionella Palego
- Department of Clinical and Experimental Medicine, Via Savi 10, University of Pisa, 56126 Pisa, Italy
- Corresponding author.
| | - Gian Carlo Demontis
- Department of Pharmacy, Via Bonanno 6, University of Pisa, 56126 Pisa, Italy
| | - Fabiana Miraglia
- Department of Pharmacy, Via Bonanno 6, University of Pisa, 56126 Pisa, Italy
| | - Gino Giannaccini
- Department of Pharmacy, Via Bonanno 6, University of Pisa, 56126 Pisa, Italy
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10
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Salobrar-García E, de Hoz R, Ramírez AI, López-Cuenca I, Rojas P, Vazirani R, Amarante C, Yubero R, Gil P, Pinazo-Durán MD, Salazar JJ, Ramírez JM. Changes in visual function and retinal structure in the progression of Alzheimer's disease. PLoS One 2019; 14:e0220535. [PMID: 31415594 PMCID: PMC6695171 DOI: 10.1371/journal.pone.0220535] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/17/2019] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Alzheimer's Disease (AD) can cause degeneration in the retina and optic nerve either directly, as a result of amyloid beta deposits, or secondarily, as a result of the degradation of the visual cortex. These effects raise the possibility that tracking ophthalmologic changes in the retina can be used to assess neurodegeneration in AD. This study aimed to detect retinal changes and associated functional changes in three groups of patients consisting of AD patients with mild disease, AD patients with moderate disease and healthy controls by using non-invasive psychophysical ophthalmological tests and optical coherence tomography (OCT). METHODS We included 39 patients with mild AD, 21 patients with moderate AD and 40 age-matched healthy controls. Both patients and controls were ophthalmologically healthy. Visual acuity, contrast sensitivity, colour perception, visual integration, and choroidal thicknesses were measured. In addition, OCT and OCT angiography (OCTA) were applied. FINDINGS Visual acuity, contrast sensitivity, colour perception, and visual integration were significantly lower in AD patients than in healthy controls. Compared to healthy controls, macular thinning in the central region was significant in the mild AD patients, while macular thickening in the central region was found in the moderate AD group. The analysis of macular layers revealed significant thinning of the retinal nerve fibre layer, the ganglion cell layer and the outer plexiform layer in AD patients relative to controls. Conversely, significant thickening was observed in the outer nuclear layer of the patients. However, mild AD was associated with significant thinning of the subfovea and the nasal and inferior sectors of the choroid. Significant superonasal and inferotemporal peripapillary thinning was observed in patients with moderate disease. CONCLUSIONS The first changes in the mild AD patients appear in the psychophysical tests and in the central macula with a decrease in the central retinal thickness. When there was a disease progression to moderate AD, psychophysical tests remained stable with respect to the decrease in mild AD, but significant thinning in the peripapillary retina and thickening in the central retina appeared. The presence of AD is best indicated based on contrast sensitivity.
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Affiliation(s)
- Elena Salobrar-García
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Rosa de Hoz
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Ana I. Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Inés López-Cuenca
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Pilar Rojas
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Servicio de Oftalmología, Hospital Universitario Gregorio Marañón, Madrid, Spain
| | - Ravi Vazirani
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Carla Amarante
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Raquel Yubero
- Unidad de Memoria, Servicio de Geriatría, Hospital Clínico San Carlos, Madrid, Spain
| | - Pedro Gil
- Unidad de Memoria, Servicio de Geriatría, Hospital Clínico San Carlos, Madrid, Spain
| | - María D. Pinazo-Durán
- Unidad de Investigación Oftalmológica «Santiago Grisolia»/FISABIO, Valencia, Spain
- Grupo de Oftalmobiología Celular y Molecular, Facultad de Medicina y Odontología, Universidad de Valencia, Valencia, Spain
| | - Juan J. Salazar
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - José M. Ramírez
- Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Inmunología, Oftalmología y ORL, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
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Melatonin as the Possible Link Between Age-Related Retinal Regeneration and the Disrupted Circadian Rhythm in Elderly. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:45-49. [PMID: 31884587 DOI: 10.1007/978-3-030-27378-1_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The association between age-related macular degeneration (AMD) and biological rhythms has been insufficiently studied; however there are several reasons to believe that impairment in circadian rhythm may affect incidence and pathogenesis of AMD. The current understanding of AMD pathology is based on age-related, cumulative oxidative damage to the retinal pigmented epithelium (RPE) partially due to impaired clearance of phagocytosed photoreceptor outer segments. In higher vertebrates, phagocytosis of the outer segments is synchronized by circadian rhythms and occurs shortly after dawn, followed by lysosomal-mediated clearance. Aging has been shown to be associated with the changes in circadian rhythmicity of melatonin production, which can be a major factor contributing to the impaired balance between phagocytosis and clearance and increased levels of reactive oxygen species resulting in degenerative changes in the retina. This minireview summarizes studies linking AMD with melatonin production and discusses challenges and perspectives of this area of research.
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Maarman GJ. Natural Antioxidants as Potential Therapy, and a Promising Role for Melatonin Against Pulmonary Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 967:161-178. [PMID: 29047086 DOI: 10.1007/978-3-319-63245-2_10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Plasma and serum samples, and lung/heart tissue of pulmonary hypertension (PH) patients and animal models of PH display elevated oxidative stress. Moreover, the severity of PH and levels of oxidative stress increase concurrently, which suggests that oxidative stress could be utilized as a biomarker for PH progression. Accumulating evidence has well established that oxidative stress is also key role player in the development of PH. Preclinical studies have demonstrated that natural antioxidants improved PH condition, and, therefore, antioxidant therapy has been proposed as a potential therapeutic strategy against PH. These natural antioxidants include medicinal plant extracts and compounds such as resveratrol and melatonin. Recent studies suggest that melatonin provides health benefit against PH, by enhancing antioxidant capacity, increasing vasodilation, counteracting lung and cardiac fibrosis, and stunting right ventricular (RV) hypertrophy/failure. This chapter comprehensively reviews and discusses a variety of natural antioxidants and their efficacy in modulating experimental PH. This chapter also demonstrates that antioxidant therapy remains a therapeutic strategy for PH, and particularly identifies melatonin as a safe, cost-effective, and promising antioxidant therapy.
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Affiliation(s)
- Gerald J Maarman
- Hatter Institute for Cardiovascular Research in Africa (HICRA) and MRC Inter-University, Cape Heart Group, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
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Dehdashtian E, Mehrzadi S, Yousefi B, Hosseinzadeh A, Reiter RJ, Safa M, Ghaznavi H, Naseripour M. Diabetic retinopathy pathogenesis and the ameliorating effects of melatonin; involvement of autophagy, inflammation and oxidative stress. Life Sci 2018; 193:20-33. [DOI: 10.1016/j.lfs.2017.12.001] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/19/2017] [Accepted: 12/01/2017] [Indexed: 12/12/2022]
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Crooke A, Huete-Toral F, Colligris B, Pintor J. The role and therapeutic potential of melatonin in age-related ocular diseases. J Pineal Res 2017; 63. [PMID: 28658514 DOI: 10.1111/jpi.12430] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022]
Abstract
The eye is continuously exposed to solar UV radiation and pollutants, making it prone to oxidative attacks. In fact, oxidative damage is a major cause of age-related ocular diseases including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. As the nature of lens cells, trabecular meshwork cells, retinal ganglion cells, retinal pigment epithelial cells, and photoreceptors is postmitotic, autophagy plays a critical role in their cellular homeostasis. In age-related ocular diseases, this process is impaired, and thus, oxidative damage becomes irreversible. Other conditions such as low-grade chronic inflammation and angiogenesis also contribute to the development of retinal diseases (glaucoma, age-related macular degeneration and diabetic retinopathy). As melatonin is known to have remarkable qualities such as antioxidant/antinitridergic, mitochondrial protector, autophagy modulator, anti-inflammatory, and anti-angiogenic, it can represent a powerful tool to counteract all these diseases. The present review analyzes the role and therapeutic potential of melatonin in age-related ocular diseases, focusing on nitro-oxidative stress, autophagy, inflammation, and angiogenesis mechanisms.
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Affiliation(s)
- Almudena Crooke
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Fernando Huete-Toral
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Basilio Colligris
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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Gupta T, Sahni D, Gupta R, Gupta S. Expanding the horizons of melatonin use: An immunohistochemical neuroanatomic distribution of MT1 and MT2 receptors in human brain and retina. J ANAT SOC INDIA 2017. [DOI: 10.1016/j.jasi.2017.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Maarman GJ, Andrew BM, Blackhurst DM, Ojuka EO. Melatonin protects against uric acid-induced mitochondrial dysfunction, oxidative stress, and triglyceride accumulation in C2C12myotubes. J Appl Physiol (1985) 2017; 122:1003-1010. [DOI: 10.1152/japplphysiol.00873.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/02/2016] [Accepted: 12/15/2016] [Indexed: 01/08/2023] Open
Abstract
Excess uric acid has been shown to induce oxidative stress, triglyceride accumulation, and mitochondrial dysfunction in the liver and is an independent predictor of type-2 diabetes. Skeletal muscle plays a dominant role in type 2 diabetes and presents a large surface area to plasma uric acid. However, the effects of uric acid on skeletal muscle are underinvestigated. Our aim was therefore to characterize the effects of excessive uric acid on oxidative stress, triglyceride content, and mitochondrial function in skeletal muscle C2C12myotubes and assess how these are modulated by the antioxidant molecule melatonin. Differentiated C2C12myotubes were exposed to 750 µM uric acid or uric acid + 10 nM melatonin for 72 h. Compared with control, uric acid increased triglyceride content by ~237%, oxidative stress by 32%, and antioxidant capacity by 135%. Uric acid also reduced endogenous ROUTINE respiration, complex II-linked oxidative phosphorylation, and electron transfer system capacities. Melatonin counteracted the effects of uric acid without further altering antioxidant capacity. Our data demonstrate that excess uric acid has adverse effects on skeletal muscle similar to those previously reported in hepatocytes and suggest that melatonin at a low physiological concentration of 10 nM may be a possible therapy against some adverse effects of excess uric acid.NEW & NOTEWORTHY Few studies have investigated the effects of uric acid on skeletal muscle. This study shows that hyperuricemia induces mitochondrial dysfunction and triglyceride accumulation in skeletal muscle. The findings may explain why hyperuricemia is an independent predictor of diabetes.
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Affiliation(s)
- Gerald J. Maarman
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, University of Cape Town, Newlands, South Africa; and
| | - Brittany M. Andrew
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, University of Cape Town, Newlands, South Africa; and
| | - Dee M. Blackhurst
- Division of Chemical Pathology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Edward O. Ojuka
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, University of Cape Town, Newlands, South Africa; and
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Aranda ML, Fleitas MFG, Dieguez H, Iaquinandi A, Sande PH, Dorfman D, Rosenstein RE. Melatonin as a Therapeutic Resource for Inflammatory Visual Diseases. Curr Neuropharmacol 2017; 15:951-962. [PMID: 28088912 PMCID: PMC5652015 DOI: 10.2174/1570159x15666170113122120] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/15/2016] [Accepted: 01/06/2017] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Uveitis and optic neuritis are prevalent ocular inflammatory diseases, and highly damaging ocular conditions. Both diseases are currently treated with corticosteroids, but they do not have adequate efficacy and are often associated with severe side effects. Thus, uveitis and optic neuritis remain a challenging field to ophthalmologists and a significant public health concern. OBJECTIVE This review summarizes findings showing the benefits of a treatment with melatonin in experimental models of these inflammatory ocular diseases. RESULTS Oxidative and nitrosative damage, tumor necrosis factor, and prostaglandin production have been involved in the pathogeny of uveitis and optic neuritis. Melatonin is an efficient antioxidant and antinitridergic, and has the ability to reduce prostaglandin and tumor necrosis factor levels both in the retina and optic nerve. Moreover, melatonin not only prevents functional and structural consequences of experimental uveitis and optic neuritis, but it is also capable of suppressing the actively ongoing ocular inflammatory response. CONCLUSIONS Since melatonin protects ocular tissues against inflammation, it could be a potentially useful anti-inflammatory therapy in ophthalmology.
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Affiliation(s)
- Marcos L. Aranda
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - María Florencia González Fleitas
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Hernán Dieguez
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Agustina Iaquinandi
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | - Pablo H. Sande
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina
| | | | - Ruth E. Rosenstein
- Address correspondence to this author at the Department of Human Biochemistry, School of Medicine, CEFyBO, University of Buenos Aires, CONICET, Paraguay 2155, 5th Floor, (1121), Buenos Aires, Argentina;, Tel: 54-11-45083672 (ext 37); Fax: 54-11-45083672 (ext 317);, E-mail:
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Melatonin in Retinal Physiology and Pathology: The Case of Age-Related Macular Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6819736. [PMID: 27688828 PMCID: PMC5027321 DOI: 10.1155/2016/6819736] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/09/2016] [Indexed: 12/16/2022]
Abstract
Melatonin, an indoleamine, is synthesized mainly in the pineal gland in a circadian fashion, but it is produced in many other organs, including the retina, which seems to be especially important as the eye is a primary recipient of circadian signals. Melatonin displays strong antioxidative properties, which predispose it to play a protective role in many human pathologies associated with oxidative stress, including premature aging and degenerative disease. Therefore, melatonin may play a role in age-related macular degeneration (AMD), a disease affecting photoreceptors, and retinal pigment epithelium (RPE) with an established role of oxidative stress in its pathogenesis. Several studies have shown that melatonin could exert the protective effect against damage to RPE cells evoked by reactive oxygen species (ROS), but it has also been reported to increase ROS-induced damage to photoreceptors and RPE. Melatonin behaves like synthetic mitochondria-targeted antioxidants, which concentrate in mitochondria at relatively high levels; thus, melatonin may prevent mitochondrial damage in AMD. The retina contains telomerase, an enzyme implicated in maintaining the length of telomeres, and oxidative stress inhibits telomere synthesis, while melatonin overcomes this effect. These features support considering melatonin as a preventive and therapeutic agent in the treatment of AMD.
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Lai YH, Hu DN, Rosen R, Sassoon J, Chuang LY, Wu KY, Wu WC. Hypoxia-induced vascular endothelial growth factor secretion by retinal pigment epithelial cells is inhibited by melatonin via decreased accumulation of hypoxia-inducible factors-1α protein. Clin Exp Ophthalmol 2016; 45:182-191. [PMID: 27409056 DOI: 10.1111/ceo.12802] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Hypoxia is the most important stimulus leading to up-regulation of vascular endothelial growth factor (VEGF) in the retina via elevation of hypoxia-inducible factors-1α (HIF-1α) protein. The purpose of this study was to test the effects of melatonin on the expression of VEGF and HIF-1α in the cultured human retinal pigment epithelial (RPE) cells under normoxia and hypoxia. METHOD An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2 ) to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without melatonin under normoxia and hypoxia. The protein and RNA levels of VEGF and HIF-1α were measured by ELISA kits and RT-PCR, respectively. RESULT Hypoxia induced a significant increase of expression and secretion of VEGF and accumulation of HIF-1α protein in RPE cells (P < 0.05). Melatonin at 10-5 to 10-8 M significantly inhibited hypoxia-induced expression, the secretion of VEGF and the accumulation of HIF-1α protein (P < 0.05), but not affected expression of VEGF and HIF-1α under normoxia (P > 0.05). CONCLUSION This study suggests that melatonin may have potential value in the prevention and treatment of various retinal diseases associated with increase of VEGF, vascular leakage and angiogenesis.
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Affiliation(s)
- Yu-Hung Lai
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Dan-Ning Hu
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA.,Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Richard Rosen
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA.,Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jodi Sassoon
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA
| | - Lea-Yea Chuang
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Kwou-Yeung Wu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Chuan Wu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
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Gianesini C, Hiragaki S, Laurent V, Hicks D, Tosini G. Cone Viability Is Affected by Disruption of Melatonin Receptors Signaling. Invest Ophthalmol Vis Sci 2016; 57:94-104. [PMID: 26780313 PMCID: PMC4727519 DOI: 10.1167/iovs.15-18235] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Previous studies have demonstrated that melatonin has an important role in the modulation of photoreceptor viability during aging and may be involved in the pathogenesis of age-related macular degeneration.This hormone exerts its influence by binding to G-protein coupled receptors named melatonin receptor 1 (MT1) and 2 (MT2). Melatonin receptors 1 and 2 activate a wide variety of signaling pathways. Methods Melatonin-proficient mice (C3H/f+/+) and melatonin-proficient mice lacking MT1 or MT2 receptors (MT1−/− and MT2−/−) were used in this study. Mice were killed at the ages of 3 and 18 months, and photoreceptor viability was determined by counting nuclei number in the outer nuclear layer (ONL). Cones were identified by immunohistochemistry using peanut agglutinin (PNA) and green/red and blue opsin antibodies. Protein kinase B (AKT) and forkhead box O (FOXO1) were assessed by Western blotting and immunohistochemistry. Results The number of nuclei in the ONL was significantly reduced in C3Hf+/+, MT1−/−, and MT2−/− mice at 18 months of age with respect to 3-month-old animals. In 18-month-old MT1−/− and MT2−/− mice, but not in C3H/f+/+, the number of cones was significantly reduced with respect to young MT1−/− and MT2−/− mice or age-matched C3H/f+/+. In C3H/f+/+, activation of the AKT-FOXO1 pathway in the photoreceptors showed a significant difference between night and day. Conclusions Our data indicate that disruption of MT1/MT2 heteromer signaling induces a reduction in the number of photoreceptors during aging and also suggest that the AKT-FOXO1 survival pathway may be involved in the mechanism by which melatonin protects photoreceptors.
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Affiliation(s)
- Coralie Gianesini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States 2Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neuro
| | - Susumu Hiragaki
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Virginie Laurent
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - David Hicks
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - Gianluca Tosini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
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Pérez-Canales JL, Rico-Sergado L, Pérez-Santonja JJ. Self-Reported Sleep Duration in Patients with Neovascular Age-Related Macular Degeneration. Ophthalmic Epidemiol 2016; 23:20-6. [PMID: 26786476 DOI: 10.3109/09286586.2015.1119288] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To examine the relationship between self-reported sleep duration and neovascular age-related macular degeneration (nAMD). METHODS This case-control study comprised 165 subjects (57 patients with nAMD and 108 controls). Controls were matched to cases by age and sex. Participants completed a questionnaire that included questions about sleep duration and quality. Four categories of sleep duration were established; <6 hours, 6-7 hours, 7-8 hours and >8 hours. Association of sleep duration and nAMD was assessed by logistic regression analysis. Multiple logistic regression models were performed to control for possible confounders. RESULTS We found a significant association between short sleep duration and nAMD (for <6 hours, odds ratio, OR, 3.29, 95% confidence interval, CI, 1.32-8.27; for 6-7 hours, OR 2.25, 95% CI 0.80-6.32; and for >8 hours, OR 1.39, 95% CI 0.53-3.73) compared with the reference category of 7-8 hours. This association remained significant after adjustment for confounders (<6 hours, OR 3.09, 95% CI 1.20-7.97). In addition, a borderline significant association was observed between self-reported very bad sleep quality and nAMD (OR 2.84, 95% CI 1.02-7.88). The highest rate of sleep medication use was found in the nAMD group (p < 0.001). CONCLUSION Our findings provide evidence to support an association between short sleep duration and nAMD. Considering strategies to improve sleep in these patients may prevent the negative effects of sleep deficiency.
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Affiliation(s)
- Jose L Pérez-Canales
- a Department of Ophthalmology , Alicante University General Hospital , Alicante , Spain
| | - Laura Rico-Sergado
- a Department of Ophthalmology , Alicante University General Hospital , Alicante , Spain
| | - Juan J Pérez-Santonja
- a Department of Ophthalmology , Alicante University General Hospital , Alicante , Spain.,b OftalVist Group , Alicante , Spain
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Nebbioso M, Plateroti AM, Pucci B, Pescosolido N. Role of the dopaminergic system in the development of myopia in children and adolescents. J Child Neurol 2014; 29:1739-46. [PMID: 24996871 DOI: 10.1177/0883073814538666] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This review summarizes the experimental evidence that supports the role of dopamine in the regulation of ocular axial growth. The most important functions attributed to dopamine are light adaptation and regulation of the retinal circadian rhythm. An increase of the retinal levels of dopamine activates D1 and D2 dopaminergic receptors present throughout the retina, generating a signal that inhibits axial growth once the eye has reached emmetropization. Researchers induced form-deprivation myopia in animal models in order to assess the different changes of ocular axial growth. Other studies have shown that phenylethylamine is an endogenous precursor-neurotransmitter capable of modulating the activity of dopamine. Considering the role of the dopaminergic system in the development of myopia (in children and adolescents) and the fact that phenylethylamine improves the consequences of a dopamine deficit, it would be interesting to study the effect of phenylethylamine on the regulation of axial growth, which represents the genesis of myopia.
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Affiliation(s)
- Marcella Nebbioso
- Department of Sense Organs, Sapienza University of Rome, Rome, Italy
| | | | - Bruna Pucci
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Nicola Pescosolido
- Department of Cardiovascular, Respiratory, Nephrology, Geriatric, and Anesthetic Sciences, Sapienza University of Rome, Rome, Italy
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Acuña-Castroviejo D, Escames G, Venegas C, Díaz-Casado ME, Lima-Cabello E, López LC, Rosales-Corral S, Tan DX, Reiter RJ. Extrapineal melatonin: sources, regulation, and potential functions. Cell Mol Life Sci 2014; 71:2997-3025. [PMID: 24554058 PMCID: PMC11113552 DOI: 10.1007/s00018-014-1579-2] [Citation(s) in RCA: 705] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/26/2014] [Accepted: 01/27/2014] [Indexed: 12/15/2022]
Abstract
Endogenous melatonin is synthesized from tryptophan via 5-hydroxytryptamine. It is considered an indoleamine from a biochemical point of view because the melatonin molecule contains a substituted indolic ring with an amino group. The circadian production of melatonin by the pineal gland explains its chronobiotic influence on organismal activity, including the endocrine and non-endocrine rhythms. Other functions of melatonin, including its antioxidant and anti-inflammatory properties, its genomic effects, and its capacity to modulate mitochondrial homeostasis, are linked to the redox status of cells and tissues. With the aid of specific melatonin antibodies, the presence of melatonin has been detected in multiple extrapineal tissues including the brain, retina, lens, cochlea, Harderian gland, airway epithelium, skin, gastrointestinal tract, liver, kidney, thyroid, pancreas, thymus, spleen, immune system cells, carotid body, reproductive tract, and endothelial cells. In most of these tissues, the melatonin-synthesizing enzymes have been identified. Melatonin is present in essentially all biological fluids including cerebrospinal fluid, saliva, bile, synovial fluid, amniotic fluid, and breast milk. In several of these fluids, melatonin concentrations exceed those in the blood. The importance of the continual availability of melatonin at the cellular level is important for its physiological regulation of cell homeostasis, and may be relevant to its therapeutic applications. Because of this, it is essential to compile information related to its peripheral production and regulation of this ubiquitously acting indoleamine. Thus, this review emphasizes the presence of melatonin in extrapineal organs, tissues, and fluids of mammals including humans.
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Affiliation(s)
- Darío Acuña-Castroviejo
- Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, Universidad de Granada, Avda. del Conocimiento s/n, Armilla, 18100, Granada, Spain,
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Gulle K, Akpolat M, Kurcer Z, Cengiz MI, Baba F, Acikgoz S. Multi-organ injuries caused by lipopolysaccharide-induced periodontal inflammation in rats: role of melatonin. J Periodontal Res 2013; 49:736-41. [DOI: 10.1111/jre.12156] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2013] [Indexed: 11/29/2022]
Affiliation(s)
- K. Gulle
- Department of Histology and Embryology; Faculty of Medicine; Bulent Ecevit University; Zonguldak Turkey
| | - M. Akpolat
- Department of Histology and Embryology; Faculty of Medicine; Bulent Ecevit University; Zonguldak Turkey
| | - Z. Kurcer
- Department of Pharmacology; Institute of Health Sciences; Bulent Ecevit University; Zonguldak Turkey
| | - M. I. Cengiz
- Department of Pharmacology; Institute of Health Sciences; Bulent Ecevit University; Zonguldak Turkey
- Department of Periodontology; Faculty of Dentistry; Bulent Ecevit University; Zonguldak Turkey
| | - F. Baba
- Department of Pathology; Selcuklu Faculty of Medicine; Selcuk University; Konya Turkey
| | - S. Acikgoz
- Department of Medical Biochemistry; Faculty of Medicine; Bulent Ecevit University; Zonguldak Turkey
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Akdogan M, Budak YU, Huysal K. Urinary 6-sulphatoxymelatonin levels in patients with senile cataracts. BMC Ophthalmol 2013; 13:46. [PMID: 24053446 PMCID: PMC3828000 DOI: 10.1186/1471-2415-13-46] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 09/09/2013] [Indexed: 01/19/2023] Open
Abstract
Background The antioxidant melatonin effectively scavenges highly toxic hydroxyl radicals. Decreases in circulating melatonin levels have been reported in patients with diseases that become more serious with advancing age. The purpose of the present study was to explore the relationship between circulatory melatonin level and the extent of senile cataracts. To this end, we assessed the urinary excretion levels of 6-sulphatoxymelatonin (aMTS6), a major metabolite of melatonin. Methods A total of 22 patients (aged 64 ± 7 years; 12 males and 10 females) with senile cataracts and 22 healthy controls (aged 61 ± 8 years, 12 males and 10 females) were studied. aMTS6 urine levels were measured using commercial ELISA kits. Each aMTS6 level was expressed as [aMTS6] (in ng)/[mg] creatinine. As the data were not normally distributed, the Mann–Whitney U-test was employed to assess the statistical validity of the difference observed. Results The aMT6 level in nocturnal urine was 17.87 ± 14.43 ng aMTS6/mg creatinine (mean ± SD) in senile cataract patients; this was 76% of the level measured in age- and gender-matched controls (23.28 ± 16.27 ng aMTS6/mg creatinine). This difference in nocturnal urine aMTS6 level between senile cataract patients and controls was not statistically significant (p = 0.358). Conclusion The urinary aMTS6 level did not differ between subjects with and without senile cataracts.
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Affiliation(s)
- Muberra Akdogan
- Department of Clinical Laboratory, Sevket Yilmaz Education and Research Hospital, Bursa, Turkey.
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Coto-Montes A, Boga JA, Rosales-Corral S, Fuentes-Broto L, Tan DX, Reiter RJ. Role of melatonin in the regulation of autophagy and mitophagy: a review. Mol Cell Endocrinol 2012; 361:12-23. [PMID: 22575351 DOI: 10.1016/j.mce.2012.04.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/15/2012] [Indexed: 01/27/2023]
Abstract
Oxidative stress plays an essential role in triggering many cellular processes including programmed cell death. Proving a relationship between apoptosis and reactive oxygen species has been the goal of numerous studies. Accumulating data point to an essential role for oxidative stress in the activation of autophagy. The term autophagy encompasses several processes including not only survival or death mechanisms, but also pexophagy, mitophagy, ER-phagy or ribophagy, depending of which organelles are targeted for specific autophagic degradation. However, whether the outcome of autophagy is survival or death and whether the initiating conditions are starvation, pathogens or death receptors, reactive oxygen species are invariably involved. The role of antioxidants in the regulation of these processes, however, has been sparingly investigated. Among the known antioxidants, melatonin has high efficacy and, in both experimental and clinical situations, its protective actions against oxidative stress are well documented. Beneficial effects against mitochondrial dysfunction have also been described for melatonin; thus, this indoleamine seems to be linked to mitophagy. The present review focuses on data and the most recent advances related to the role of melatonin in health and disease, on autophagy activation in general, and on mitophagy in particular.
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Affiliation(s)
- Ana Coto-Montes
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Tosini G, Baba K, Hwang CK, Iuvone PM. Melatonin: an underappreciated player in retinal physiology and pathophysiology. Exp Eye Res 2012; 103:82-9. [PMID: 22960156 DOI: 10.1016/j.exer.2012.08.009] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 12/14/2022]
Abstract
In the vertebrate retina, melatonin is synthesized by the photoreceptors with high levels of melatonin at night and lower levels during the day. Melatonin exerts its influence by interacting with a family of G-protein-coupled receptors that are negatively coupled with adenylyl cyclase. Melatonin receptors belonging to the subtypes MT(1) and MT(2) have been identified in the mammalian retina. MT(1) and MT(2) receptors are found in all layers of the neural retina and in the retinal pigmented epithelium. Melatonin in the eye is believed to be involved in the modulation of many important retinal functions; it can modulate the electroretinogram (ERG), and administration of exogenous melatonin increases light-induced photoreceptor degeneration. Melatonin may also have protective effects on retinal pigment epithelial cells, photoreceptors and ganglion cells. A series of studies have implicated melatonin in the pathogenesis of age-related macular degeneration, and melatonin administration may represent a useful approach to prevent and treat glaucoma. Melatonin is used by millions of people around the world to retard aging, improve sleep performance, mitigate jet lag symptoms, and treat depression. Administration of exogenous melatonin at night may also be beneficial for ocular health, but additional investigation is needed to establish its potential.
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Affiliation(s)
- Gianluca Tosini
- Circadian Rhythms and Sleep Disorders Program, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA.
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Venegas C, Cabrera-Vique C, García-Corzo L, Escames G, Acuña-Castroviejo D, López LC. Determination of coenzyme Q10, coenzyme Q9, and melatonin contents in virgin argan oils: comparison with other edible vegetable oils. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:12102-12108. [PMID: 22007968 DOI: 10.1021/jf203428t] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Virgin argan oil possesses high antioxidant capacity (AC), which may be partially explained by its high content in antioxidant molecules such as polyphenols and tocopherols. However, the content in other antioxidant molecules, for example, coenzyme Q10 (CoQ(10)), coenzyme Q9 (CoQ(9)), and melatonin (Mel), which have been identified in other edible vegetable oils, have not been evaluated in virgin argan oil. Consequently, it was decided to evaluate the contents of CoQ(10), CoQ(9), and Mel in virgin argan oils and compare the results to those obtained in extra virgin olive oils and some varieties of seed oils. By the use of sensitive HPLC-EC/F methods, the results showed that virgin argan oil is a rich source of CoQ(10) and Mel, but no CoQ(9) was detected. Extra virgin olive oil showed higher levels of CoQ(10) and lower levels of Mel than virgin argan oil. Between the seed oil samples, only virgin soybean oil showed higher CoQ(10) and Mel levels than virgin argan oil. The results may be relevant for the contribution of CoQ(10) and Mel to the biological activities of virgin argan oil.
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Affiliation(s)
- Carmen Venegas
- Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, Universidad de Granada, Granada, Spain
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Day and Night GSH and MDA Levels in Healthy Adults and Effects of Different Doses of Melatonin on These Parameters. Int J Cell Biol 2011; 2011:404591. [PMID: 21647290 PMCID: PMC3103893 DOI: 10.1155/2011/404591] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 03/02/2011] [Indexed: 11/17/2022] Open
Abstract
The pineal secretory product melatonin (chemically, N-acetyl-5-methoxytryptamine) acts as an effective antioxidant and free-radical scavenger and plays an important role in several physiological functions such as sleep induction, immunomodulation, cardiovascular protection, thermoregulation, neuroprotection, tumor-suppression and oncostasis. Membrane lipid-peroxidation in terms of malondialdehyde (MDA) and intracellular glutathione (GSH) is considered to be a reliable marker of oxidative stress. The present work was undertaken to study the modulating effect of melatonin on MDA and GSH in human erythrocytes during day and night. Our observation shows the modulation of these two biomarkers by melatonin, and this may have important therapeutic implications. In vitro dose-dependent effect of melatonin also showed variation during day and night. We explain our observations on the basis of melatonin's antioxidative function and its effect on the fluidity of plasma membrane of red blood cells. Rhythmic modulation of MDA and GSH contents emphasized the role of melatonin as an antioxidant and its function against oxidative stress.
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Rosenstein RE, Pandi-Perumal SR, Srinivasan V, Spence DW, Brown GM, Cardinali DP. Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis. J Pineal Res 2010; 49:1-13. [PMID: 20492443 DOI: 10.1111/j.1600-079x.2010.00764.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several lines of evidence support the view that increased free radical generation and altered nitric oxide (NO) metabolism play a role in the pathogenesis of highly prevalent ocular diseases, such as glaucoma and uveitis. Data are discussed indicating that melatonin, being an efficient antioxidant that displays antinitridergic properties, has a promising role in the treatment of these ocular dysfunctions. Melatonin synthesis occurs in the eye of most species, and melatonin receptors are localized in different ocular structures. In view of the fact that melatonin lacks significant adverse collateral effects even at high doses, the application of melatonin could potentially protect ocular tissues by effectively scavenging free radicals and excessive amounts of NO generated in the glaucomatous or uveitic eye.
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Affiliation(s)
- Ruth E Rosenstein
- Department of Human Biochemistry, School of Medicine, CEFyBO, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
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Baba K, Pozdeyev N, Mazzoni F, Contreras-Alcantara S, Liu C, Kasamatsu M, Martinez-Merlos T, Strettoi E, Iuvone PM, Tosini G. Melatonin modulates visual function and cell viability in the mouse retina via the MT1 melatonin receptor. Proc Natl Acad Sci U S A 2009; 106:15043-8. [PMID: 19706469 PMCID: PMC2736407 DOI: 10.1073/pnas.0904400106] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Indexed: 11/18/2022] Open
Abstract
A clear demonstration of the role of melatonin and its receptors in specific retinal functions is lacking. The present study investigated the distribution of MT1 receptors within the retina, and the scotopic and photopic electroretinograms (ERG) and retinal morphology in wild-type (WT) and MT1 receptor-deficient mice. MT1 receptor transcripts were localized in photoreceptor cells and in some inner retinal neurons. A diurnal rhythm in the dark-adapted ERG responses was observed in WT mice, with higher a- and b-wave amplitudes at night, but this rhythm was absent in mice lacking MT1 receptors. Injection of melatonin during the day decreased the scotopic response threshold and the amplitude of the a- and b-waves in the WT mice, but not in the MT1(-/-) mice. The effects of MT1 receptor deficiency on retinal morphology was investigated at three different ages (3, 12, and 18 months). No differences between MT1(-/-) and WT mice were observed at 3 months of age, whereas at 12 months MT1(-/-) mice have a significant reduction in the number of photoreceptor nuclei in the outer nuclear layer compared with WT controls. No differences were observed in the number of cells in inner nuclear layer or in ganglion cells at 12 months of age. At 18 months, the loss of photoreceptor nuclei in the outer nuclear layer was further accentuated and the number of ganglion cells was also significantly lower than that of controls. These data demonstrate the functional significance of melatonin and MT1 receptors in the mammalian retina and create the basis for future studies on the therapeutic use of melatonin in retinal degeneration.
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MESH Headings
- Adaptation, Biological
- Aging
- Animals
- Cell Survival
- Darkness
- Electroretinography
- Gene Expression Regulation
- Melatonin/metabolism
- Mice
- Mice, Knockout
- RNA, Messenger/genetics
- Receptor, Melatonin, MT1/deficiency
- Receptor, Melatonin, MT1/genetics
- Receptor, Melatonin, MT1/metabolism
- Retina/cytology
- Retina/metabolism
- Retinal Degeneration/metabolism
- Retinal Degeneration/therapy
- Vision, Ocular
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Affiliation(s)
- Kenkichi Baba
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310
| | - Nikita Pozdeyev
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Francesca Mazzoni
- Istituto di Neuroscience, Consiglio Nazionale delle Ricerche, Pisa 56100, Italy
| | | | - Cuimei Liu
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310
| | - Manami Kasamatsu
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310
| | | | - Enrica Strettoi
- Istituto di Neuroscience, Consiglio Nazionale delle Ricerche, Pisa 56100, Italy
| | - P. Michael Iuvone
- Departments of Ophthalmology and Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Gianluca Tosini
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310
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Żmijewski MA, Sweatman TW, Slominski AT. The melatonin-producing system is fully functional in retinal pigment epithelium (ARPE-19). Mol Cell Endocrinol 2009; 307:211-6. [PMID: 19409957 PMCID: PMC2728552 DOI: 10.1016/j.mce.2009.04.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 04/20/2009] [Accepted: 04/22/2009] [Indexed: 11/19/2022]
Abstract
Since melatonin production has been documented in extrapineal and extraneuronal tissues, we investigated the expression of molecular elements of the melatoninergic system in human RPE cells (ARPE-19). The expression of key enzymes for melatonin synthesis: tryptophan hydroxylases (TPH1 and TPH2); arylalkylamine N-acetyltransferase (AANAT) and hydroxyindole-O-methyltransferase (HIOMT) was detected in ARPE-19 cells using RT-PCR. TPH1 and AANAT proteins were detected in ARPE by Western blotting, while sequential metabolism of tryptophan, serotonin and N-acetylserotonin to melatonin was shown by RP-HPLC. We also demonstrated, by means of RT-PCR, that ARPE expressed mRNA encoding the melatonin receptors: MT2 (but not MT1), two isoforms of nuclear receptor (RORalpha1 and RORalpha4/RZR1), and quinone oxidoreductase (NQO2). By analogy with other peripheral tissues, for example the skin, the expression of these metabolic elements in RPE cells suggests that the RPE represents an additional source of melatonin in the eye, to regulate local homeostasis and prevent from oxidative damage in intra-, auto- and/or paracrine fashions.
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Affiliation(s)
- Michał A. Żmijewski
- Department of Molecular Enzymology, Intercollegiate Faculty of Biotechnology of University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Trevor W. Sweatman
- Department of Pharmacology, Center for Anticancer Drug Research, Center for Anticancer Drug Research, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Andrzej T. Slominski
- Department of Pathology and Laboratory Medicine, Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, USA
- Corresponding author at: Department of Pathology and Laboratory Medicine, Center for Cancer Research, University of Tennessee Health Science Center, 930 Madison Avenue, RM525, Memphis, TN 38163, USA. Tel.: +1 901 448 3741; fax: +1 901 448 6979. E-mail address: (A.T. Slominski)
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Karbownik M, Reiter RJ. Antioxidative Effects of Melatonin in Protection Against Cellular Damage Caused by Ionizing Radiation. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1525-1373.2000.22502.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Lundmark PO, Pandi-Perumal SR, Srinivasan V, Cardinali DP. Role of melatonin in the eye and ocular dysfunctions. Vis Neurosci 2007; 23:853-62. [PMID: 17266777 DOI: 10.1017/s0952523806230189] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2006] [Accepted: 08/02/2006] [Indexed: 12/15/2022]
Abstract
Melatonin is a ubiquitous molecule and widely distributed in nature, with functional activity occurring in unicellular organisms, plants, fungi, and animals. Several studies have indicated that melatonin synthesis occurs in the retina of most vertebrates, including mammals. The retinal biosynthesis of melatonin and the mechanisms involved in the regulation of this process have been extensively studied. Circadian clocks located in the photoreceptors and retinal neurons regulate melatonin synthesis in the eye. Photoreceptors, dopaminergic amacrine neurons, and horizontal cells of the retina, corneal epithelium, stroma endothelium, and the sclera all have melatonin receptors, indicating a widespread ocular function for melatonin. In addition, melatonin is an effective antioxidant which scavenges free radicals and up-regulates several antioxidant enzymes. It also has a strong antiapoptotic signaling function, an effect that it exerts even during ischemia. Melatonin cytoprotective properties may have practical implications in the treatment of ocular diseases, like glaucoma and age-related macular degeneration.
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Affiliation(s)
- Per O Lundmark
- Department of Optometry and Vision Sciences, Buskerud University College, Kongsberg, Norway
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Lundmark PO, Pandi-Perumal SR, Srinivasan V, Cardinali DP, Rosenstein RE. Melatonin in the eye: implications for glaucoma. Exp Eye Res 2006; 84:1021-30. [PMID: 17174303 DOI: 10.1016/j.exer.2006.10.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 10/04/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
Melatonin synthesis occurs in the retina of most animals as well as in humans. Circadian oscillators that control retinal melatonin synthesis have been identified in the eyes of different animal species. The presence of melatonin receptors is demonstrable by immunocytochemical studies of ocular tissues. These receptors may have different functional roles in different parts of the eye. In view that melatonin is a potent antioxidant molecule, it can be effective in scavenging free radicals that are generated in ocular tissues. By this mechanism melatonin could protect the ocular tissues against disorders like glaucoma, age-related macular degeneration, retinopathy of prematurity, photo-keratitis and cataracts. Although an increased intraocular pressure is an important risk factor in glaucoma, other concomitant phenomena like increased glutamate levels, altered nitric oxide metabolism and increased free radical generation seem to play a significant role in its pathogenesis. Data are discussed indicating that melatonin, being an efficient antioxidant with antinitridergic properties, has a promising role in the treatment and management of glaucoma.
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Affiliation(s)
- Per O Lundmark
- Department of Optometry and Vision Sciences, Buskerud University College, Kongsberg, 3601 Ko, Norway
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36
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Mainster MA. Violet and blue light blocking intraocular lenses: photoprotection versus photoreception. Br J Ophthalmol 2006; 90:784-92. [PMID: 16714268 PMCID: PMC1860240 DOI: 10.1136/bjo.2005.086553] [Citation(s) in RCA: 380] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2006] [Indexed: 11/04/2022]
Abstract
AIM To analyse how intraocular lens (IOL) chromophores affect retinal photoprotection and the sensitivity of scotopic vision, melanopsin photoreception, and melatonin suppression. METHODS Transmittance spectra of IOLs, high pass spectral filters, human crystalline lenses, and sunglasses are used with spectral data for acute ultraviolet (UV)-blue photic retinopathy ("blue light hazard" phototoxicity), aphakic scotopic luminous efficiency, melanopsin sensitivity, and melatonin suppression to compute the effect of spectral filters on retinal photoprotection, scotopic sensitivity, and circadian photoentrainment. RESULTS Retinal photoprotection increases and photoreception decreases as high pass filters progressively attenuate additional short wavelength light. Violet blocking IOLs reduce retinal exposure to UV (200-400 nm) radiation and violet (400-440 nm) light. Blue blocking IOLs attenuate blue (440-500 nm) and shorter wavelength optical radiation. Blue blocking IOLs theoretically provide better photoprotection but worse photoreception than conventional UV only blocking IOLs. Violet blocking IOLs offer similar UV-blue photoprotection but better scotopic and melanopsin photoreception than blue blocking IOLs. Sunglasses provide roughly 50% more UV-blue photoprotection than either violet or blue blocking IOLs. CONCLUSIONS Action spectra for most retinal photosensitisers increase or peak in the violet part of the spectrum. Melanopsin, melatonin suppression, and rhodopsin sensitivities are all maximal in the blue part of the spectrum. Scotopic sensitivity and circadian photoentrainment decline with ageing. UV blocking IOLs provide older adults with the best possible rhodopsin and melanopsin sensitivity. Blue and violet blocking IOLs provide less photoprotection than middle aged crystalline lenses, which do not prevent age related macular degeneration (AMD). Thus, pseudophakes should wear sunglasses in bright environments if the unproved phototoxicity-AMD hypothesis is valid.
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Affiliation(s)
- M A Mainster
- PhD, MD, FRCOphth, Department of Ophthalmology, MS3009, University of Kansas Medical School, 3901 Rainbow Boulevard, Kansas City, KS 66160-7379, USA.
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Srinivasan V, Pandi-Perumal SR, Cardinali DP, Poeggeler B, Hardeland R. Melatonin in Alzheimer's disease and other neurodegenerative disorders. Behav Brain Funct 2006; 2:15. [PMID: 16674804 PMCID: PMC1483829 DOI: 10.1186/1744-9081-2-15] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 05/04/2006] [Indexed: 12/15/2022] Open
Abstract
Increased oxidative stress and mitochondrial dysfunction have been identified as common pathophysiological phenomena associated with neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). As the age-related decline in the production of melatonin may contribute to increased levels of oxidative stress in the elderly, the role of this neuroprotective agent is attracting increasing attention. Melatonin has multiple actions as a regulator of antioxidant and prooxidant enzymes, radical scavenger and antagonist of mitochondrial radical formation. The ability of melatonin and its kynuramine metabolites to interact directly with the electron transport chain by increasing the electron flow and reducing electron leakage are unique features by which melatonin is able to increase the survival of neurons under enhanced oxidative stress. Moreover, antifibrillogenic actions have been demonstrated in vitro, also in the presence of profibrillogenic apoE4 or apoE3, and in vivo, in a transgenic mouse model. Amyloid-β toxicity is antagonized by melatonin and one of its kynuramine metabolites. Cytoskeletal disorganization and protein hyperphosphorylation, as induced in several cell-line models, have been attenuated by melatonin, effects comprising stress kinase downregulation and extending to neurotrophin expression. Various experimental models of AD, PD and HD indicate the usefulness of melatonin in antagonizing disease progression and/or mitigating some of the symptoms. Melatonin secretion has been found to be altered in AD and PD. Attempts to compensate for age- and disease-dependent melatonin deficiency have shown that administration of this compound can improve sleep efficiency in AD and PD and, to some extent, cognitive function in AD patients. Exogenous melatonin has also been reported to alleviate behavioral symptoms such as sundowning. Taken together, these findings suggest that melatonin, its analogues and kynuric metabolites may have potential value in prevention and treatment of AD and other neurodegenerative disorders.
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Affiliation(s)
- V Srinivasan
- Department of Physiology, School of Medical Sciences, University Sains Malaysia, Kampus Kesihatan, 16150, Kubang kerian, Kelantan, Malaysia
| | - SR Pandi-Perumal
- Comprehensive Center for Sleep Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Mount Sinai School of Medicine, 1176 – 5Avenue, New York, NY 10029, USA
| | - DP Cardinali
- Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, 1121, Buenos Aires, Argentina
| | - B Poeggeler
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Goettingen, Berliner Str. 28, D-37073 Goettingen, Germany
| | - R Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Goettingen, Berliner Str. 28, D-37073 Goettingen, Germany
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Monobe M, Hino M, Sumi M, Uzawa A, Hirayama R, Ando K, Kojima S. Protective effects of melatonin on gamma-ray induced intestinal damage. Int J Radiat Biol 2006; 81:855-60. [PMID: 16484154 DOI: 10.1080/09553000600554804] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To examine the protective effects of melatonin on intestinal damage induced by gamma-rays. MATERIALS AND METHODS Six-week-old Slc:ICR male mice were used. Mice were given whole-body irradiation at various exposure doses (7-21 Gy) with (137)Cs gamma-rays (0.98 Gy/min). The mice were orally administered 1 ml of either 1% carboxymethyl cellulose sodium salt (CMC) or melatonin (1, 5, 10 or 20 mg/ml) freshly prepared as a uniform suspension in CMC before or after irradiation. The concentrations of plasma melatonin were determined by the radioimmunoassay (RIA) method. The mice were killed at 3.5 days after the exposure. The jejunum was removed, fixed in formalin and then stained with hematoxylin and eosin. The numbers of crypts per transverse circumference were counted using a microscope for 10 histological sections of each mouse. RESULTS The intestinal damage caused by gamma-ray irradiation was prevented by melatonin correlating to dosage. The D(0) (slope of the dose-survival curve) value significantly (p < 0.05) increased from 1.55 +/- 0.19 (mean +/- SD) Gy to 1.98 +/- 0.16 Gy by orally administering 20 mg melatonin 30 min before irradiation. The radioprotective effect of melatonin continued for 6 h after the administration. CONCLUSIONS Melatonin is judged to be a potential protector against intestinal damage associated with radiotherapy. Further experimental and clinical studies on this subject are needed to allow its use for radiotherapy.
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Affiliation(s)
- Manami Monobe
- Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda-shi, Chiba, Japan.
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Siu AW, Maldonado M, Sanchez-Hidalgo M, Tan DX, Reiter RJ. Protective effects of melatonin in experimental free radical-related ocular diseases. J Pineal Res 2006; 40:101-9. [PMID: 16441546 DOI: 10.1111/j.1600-079x.2005.00304.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine with a range of antioxidative properties. Melatonin is endogenously produced in the eye and in other organs. Current evidence suggests that melatonin may act as a protective agent in ocular conditions such as photo-keratitis, cataract, glaucoma, retinopathy of prematurity and ischemia/reperfusion injury. These diseases are sight-threatening and they currently remain, for the most part, untreatable. The pathogenesis of these conditions is not entirely clear but oxidative stress has been proposed as one of the causative factors. Elevated levels of various reactive oxygen and nitrogen species have been identified in diseased ocular structures. These reactants damage the structure and deplete the eye of natural defense systems, such as the antioxidant, reduced glutathione, and the antioxidant enzyme superoxide dismutase. Oxidative damage in the eye leads to apoptotic degeneration of retinal neurons and fluid accumulation. Retinal degeneration decreases visual sensitivity and even a small change in the fluid content of the cornea and crystalline lens is sufficient to disrupt ocular transparency. In the eye, melatonin is produced in the retina and in the ciliary body. Continuous regeneration of melatonin in the eye offers a frontier antioxidative defense for both the anterior and posterior eye. However, melatonin production is minimal in newborns and its production gradually wanes in aging individuals as indicated by the large drop in circulating blood concentrations of the indoleamine. These individuals are possibly at risk of contracting degenerative eye diseases that are free radical-based. Supplementation with melatonin, a potent antioxidant, in especially the aged population should be considered as a prophylaxis to preserve visual functions. It may benefit many individuals worldwide, especially in countries where access to medical facilities is limited.
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Affiliation(s)
- Andrew W Siu
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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Abstract
Recently, fluphenazine, a phenothiazine neuroleptic, has been associated with idiosyncratic retinopathy. Neuroleptic-induced retinopathy appears to be isolated to only a few structurally related phenothiazines, suggesting that the causality is not the result of dopamine antagonism. The chemical structure of fluphenazine is very similar to that of chlorpromazine and thioridazine, agents known to produce retinopathy. Like chlorpromazine and thioridazine, fluphenazine may be oxidized by retinal cytochrome P450 and/or myeloperoxidase to an electrophile, producing injury in susceptible patients.
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Affiliation(s)
- Steven M Toler
- Clinical Pharmacology, Pfizer Global Research and Development, Pfizer Inc., New London, CT 06320, USA.
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Barun S, Ekingen G, Mert Vural I, Türkyilmaz Z, Başaklar C, Kale N, Sevim Ercan Z, Sarioğlu Y. The effects of melatonin on electrical field stimulation-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia after unilateral testicular torsion/detorsion. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:351-8. [PMID: 16003545 DOI: 10.1007/s00210-005-1073-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Accepted: 05/17/2005] [Indexed: 10/25/2022]
Abstract
It is not known whether there is an impairment in vas deferens motility after unilateral testicular torsion/detorsion. Therefore, we aimed to determine whether the electrical field stimulation (EFS)-evoked biphasic contractions are altered in ipsilateral and contralateral rat vasa deferentia obtained from animals exposed to the unilateral testicular torsion/detorsion procedure. We also evaluated the effects of melatonin (MLT), which is a strong antioxidant, on these contractile responses. Rats were subjected to torsion of the left testis for 2 h and then detorsion was performed. Contractility studies were carried out 2 h or 24 h after detorsion. Vas deferens strips were prepared from both the ipsilateral and the contralateral site 2 h or 24 h after the detorsion procedure to record EFS-evoked biphasic twitch responses. The same experimental protocol was repeated for the MLT-treated rats. Both phases of EFS-evoked contractions were decreased after torsion/detorsion in the ipsilateral vas deferens. MLT treatment increased torsion/detorsion-induced reduction of both phases of contractions after 2 h and 24 h. In the contralateral vas deferens, the first phase of EFS-evoked contractions was not changed, while the second phase of contractions was diminished 2 h and 24 h after detorsion. Although MLT decreased the second phase of contractions 2 h and 24 h after detorsion, it reduced the first phase of contractions only 2 h after detorsion. These results suggest that MLT produces an inhibition on EFS-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia following unilateral testicular torsion/detorsion in the rat.
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Affiliation(s)
- Süreyya Barun
- Department of Pharmacology, Medical School, Gazi University, Beşevler, 06510 Ankara, Turkey.
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42
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Das UN. A defect in the activity of Delta6 and Delta5 desaturases may be a factor predisposing to the development of insulin resistance syndrome. Prostaglandins Leukot Essent Fatty Acids 2005; 72:343-50. [PMID: 15850715 DOI: 10.1016/j.plefa.2005.01.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 01/04/2005] [Indexed: 11/24/2022]
Abstract
GLUT-4 (glucose transporter) receptor, tumor necrosis factor-alpha (TNF-alpha), interleukins-6 (IL-6), daf-genes and PPARs (peroxisomal proliferation activator receptors) play a role in the development of insulin resistance syndrome and associated conditions. But, the exact interaction between these molecules/factors and the mechanism(s) by which they produce insulin resistance syndrome is not clear. I propose that a defect in the activity of the enzymes Delta6 and Delta5 desaturases that are essential for the formation of long chain metabolites of essential fatty acids, linoleic acid and alpha-linolenic acid, is a factor in the development of insulin resistance syndrome. Long chain polyunsaturated fatty acids (LCPUFAs) increase cell membrane fluidity and enhance the number of insulin receptors and the affinity of insulin to its receptors; suppress TNF-alpha, IL-6, macrophage migration inhibitory factor (MIF) and leptin synthesis; increase the number of GLUT-4 receptors, serve as endogenous ligands of PPARs, modify lipolysis, and regulate the balance between pro- and anti-oxidants, and thus, play a critical role in the pathogenesis of insulin resistance. In the nematode, Caenorhabditis elegans, the protein encoded by daf-2 is 35% identical to the human insulin receptor; daf-7 codes a transforming growth factor-beta (TGF-beta) type signal and daf-16 enhances superoxide dismutase (SOD) expression. Melatonin has anti-oxidant actions similar to daf-16, TGF-beta and SOD. Calorie restriction enhances the activity of Delta6 and Delta5 desaturases, melatonin production, decreases daf-2 signaling, free radical generation, and augments anti-oxidant defenses that may explain the beneficial effect of diet control in the management of obesity, insulin resistance, and type II diabetes mellitus. These evidences suggest that the activities of Delta6 and Delta5 enzymes play a critical role in the expression and regulation of GLUT-4, TNF-alpha, IL-6, MIF, daf-genes, melatonin, and leptin by modulating the synthesis and tissue concentrations of LCPUFAs. Caloric restriction delays ageing by activating Sir 2 deacetylase in yeast, and expression of Sir 2 (SIRT1) in human cells. Both insulin and insulin-like growth factor-1 (IGF-1) attenuated this response. SIRT1 sequesters the proapoptotic factor Bax, prevents stress-induced apoptosis of cells, and thus, prolongs survival. In addition, SIRT1 repressed PPAR-gamma, and overexpression of SIRT1 attenuated adipogenesis, and upregulation of SIRT in differentiated fat cells triggered lipolysis and loss of fat, events that are known to attenuate insulin resistance and prolong life span. It remains to be seen whether LCPUFAs have a regulatory role in SIRT1 expression and control Sir 2 deacetylase activity. Thus, calorie restriction or reduced food intake has a role not only in the pathobiology of insulin resistance, but also in other associated conditions such as obesity, type II diabetes mellitus, ageing, and longevity.
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Affiliation(s)
- Undurti N Das
- UND Life Sciences, 1083 Main Street, Walpole, MA 02081, USA.
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Wang H, Wei W, Shen YX, Dong C, Zhang LL, Wang NP, Yue L, Xu SY. Protective effect of melatonin against liver injury in mice induced by Bacillus Calmette-Guerin plus lipopolysaccharide. World J Gastroenterol 2004; 10:2690-6. [PMID: 15309720 PMCID: PMC4572194 DOI: 10.3748/wjg.v10.i18.2690] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To investigate the effects and mechanisms of melatonin on immunological liver injury in mice.
METHODS: A model of liver injury was induced by tail vein injection of Bacillus Calmette Guerin (BCG) and lipopolysaccharide (LPS) in mice. Kupffer cells and hepatocytes were isolated and cultured according to a modified two-step collagenase perfusion technique. Levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and nitric oxide (NO), content of malondiadehyde (MDA), activity of superoxide dismutase (SOD), were measured by biochemical methods. Tumor necrosis factor-α (TNF-α) activity was determined by RIA. Interleukin (IL)-1 activity was measured by thymocyte proliferation bioassay. Hepatic tissue sections were stained with hematoxylin and eosin and examined under a light microscope.
RESULTS: Immunological liver injury induced by BCG+LPS was successfully duplicated. Serum transaminase (ALT, AST) activities were significantly decreased by melatonin (0.25, 1.0, 4.0 mg/kg bm). Meanwhile, MDA content was decreased and SOD in liver homogenates was upregulated. Furthermore, pro-inflammatory mediators (TNF-α, IL-1, NO) in serum and liver homogenates were significantly reduced by melatonin. Histological examination demonstrated that melatonin could attenuate the area and extent of necrosis, reduce the immigration of inflammatory cells. In in vitro experiment, TNF-α was inhibited at the concentrations of 10-8-10-6 mol/L of melatonin, while IL-1 production of Kupffer cells induced by LPS (5 μg/mL) was decreased only at the concentration of 10-6 mol/L of melatonin, but no effect on NO production was observed. Immunological liver injury model in vitro was established by incubating hepatocytes with BCG- and LPS-induced Kupffer cells. Activities of ALT, TNF-α, IL-1, and MDA in supernatant were significantly increased. Melatonin had little effect on the level of ALT, but reduced the content of TNF-α and MDA at concentrations of 10-7-10-5 mol/L and decreased the content of IL-1 at concentrations of 10-6-10-5 mol/L.
CONCLUSION: Melatonin could significantly protect liver injury in mice, which was related to free radical scavenging, increased SOD activity and pro-inflammatory mediators.
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Affiliation(s)
- Hua Wang
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei 230032, Anhui Province, China
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Siu AW, Ortiz GG, Benitez-King G, To CH, Reiter RJ. Effects of melatonin on the nitric oxide treated retina. Br J Ophthalmol 2004; 88:1078-81. [PMID: 15258029 PMCID: PMC1772281 DOI: 10.1136/bjo.2003.037879] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS Nitric oxide (NO) is a free radical which reportedly causes damage to living cells. This study evaluated the damaging effect of NO and the protection of melatonin on the retina in vivo. METHODS Female Wistar rats (230-250 g) received two intraperitoneal injections of either melatonin (5 mg/kg) or vehicle alone. After general anaesthesia, the animals received 1 microl intravitreal injections of 0.9% saline and 1 mM sodium nitroprusside (SNP) into the right eye and the left eye, respectively. The animals were divided into two groups and then sacrificed after 24 hours (day 1) and 96 hours (day 4). The mean inner retinal layer thickness (mIRLT), the number of retinas expressing hyperchromatic (HC) nuclei in the inner nuclear layer (INL) and the apoptotic ganglion cell detection were compared. RESULTS After 1 day, SNP significantly increased the mIRLT by 45% (p = 0.004), initiated more INL nuclear HC expression (p = 0.01) and apoptotic nuclei (p<0.05) compared with the control eyes. Injection of melatonin ameliorated these changes. On day 4, SNP demonstrated similar effects in all parameters on the retina. After the injection of melatonin, both INL HC expression and apoptotic ganglion nuclei in the SNP treated eyes were similar to the controls but the mIRLT was significantly greater than in controls (p = 0.006). CONCLUSION Uncontrolled NO elevation caused morphological and nuclear changes in the retina. Melatonin significantly suppressed the NO induced increase in mIRLT, INL HC expression, and apoptotic ganglion cells on day 1, but not after day 4. Melatonin may have a protective role in the NO elevated retina.
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Affiliation(s)
- A W Siu
- Division of Neurociencias, Centro de Investigacion Biomedical de Occidente, Guadalajara, Jalisco, Mexico.
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45
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Liang FQ, Green L, Wang C, Alssadi R, Godley BF. Melatonin protects human retinal pigment epithelial (RPE) cells against oxidative stress. Exp Eye Res 2004; 78:1069-75. [PMID: 15109913 DOI: 10.1016/j.exer.2004.02.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 02/10/2004] [Indexed: 11/20/2022]
Abstract
Oxidative stress is involved in the pathogenesis of age-related macular degeneration (AMD). Administration of conventional antioxidants has been shown to slow the progression of AMD and vision loss. Melatonin, an endogenous neurohormone produced by the pineal gland and retina, has been reported to be a potent antioxidant and free radical scavenger. In this study we tested whether melatonin can protect retinal pigment epithelial (RPE) cells against hydrogen peroxide (H(2)O(2))-induced cell death. Since mitochondrial DNA (mtDNA) is preferentially susceptible to oxidative damage, we tested whether melatonin can reduce H(2)O(2)-induced mtDNA lesions. A human RPE cell line (ARPE-19) was cultured and exposed to H(2)O(2) (100 and 200 microm) for 1 hr to induce cell death. Prior to H(2)O(2) treatment, cells were treated with various concentrations (0.1-200 microm) of melatonin for 2, 24 or 72 hr. Control cells received either melatonin or ethanol alone. Cell viability, as determined by MTT assay, showed no significant (P>0.05) protection against H(2)O(2) toxicity in cells receiving 2- and 24-hr pretreatment of melatonin at either concentration. However, when melatonin was administered diurnally for 3 consecutive days, this prolonged treatment markedly reduced H(2)O(2)-induced cell death (P>0.05) MtDNA damage, as assessed with quantitative PCR, was significantly decreased (P<0.05) in RPE cells pretreated with melatonin as compared to those without melatonin treatment. These results suggest that melatonin may play a role in protecting RPE cells from oxidative stress.
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Affiliation(s)
- Fong-Qi Liang
- Retina Foundation of Sothwest, Dallas, TX 75231, USA.
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46
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Abstract
What is an antioxidant? Can one, at a cellular level, speak of direct and indirect antioxidants? Can oxidative stress be quantified and characterized? What are the oxidant species that may have regulatory functions in a cell? Since the above concepts have become of frequent use in all Journals, it may be appropriate if some critical thinking outlined in this review could become available to a broad public.
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Affiliation(s)
- Angelo Azzi
- Institute of Biochemistry and Molecular Biology, University of Bern, Switzerland.
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47
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Guajardo MH, Terrasa AM, Catalá A. Protective effect of indoleamines on in vitro ascorbate-Fe2+ dependent lipid peroxidation of rod outer segment membranes of bovine retina. J Pineal Res 2003; 35:276-82. [PMID: 14521634 DOI: 10.1034/j.1600-079x.2003.00087.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Rod outer segment membranes (ROS) are highly vulnerable to autooxidation because of their high content of long chain polyunsaturated fatty acids (PUFAs). Melatonin and N-acetylserotonin are indoleamines synthesized in the pineal gland, retina and other tissues. These compounds are free radical scavengers and indirect antioxidants because of their stimulatory effect on antioxidative enzymes. We compared the in vitro protective effect of melatonin and N-acetylserotonin on the ascorbate-Fe2+ induced lipid peroxidation of PUFAs located in ROS membranes. This process was measured by chemiluminescence and fatty acid composition of total lipids of ROS. We assayed increasing concentrations of melatonin (0-10 mm) and N-acetylserotonin (0-2 mm). In both cases the total cpm originated from light emission (chemiluminescence) was found to be lower in those membranes incubated in the presence of either melatonin or N-acetylserotonin; this decreased proportional to the concentration of the indole. Thus, 10 mm melatonin and 2 mm N-acetylserotonin produced a reduction of 51 +/- 6 and 100% in the total chemiluminescene (lipid peroxidation), respectively. We also noticed a PUFAs protection: the docosahexaenoic acid content decreased considerably when the membranes were submitted to oxidative damage. This reduction was from 37.6 +/- 2.1% in the native membranes to 6.2 +/- 0.8% in those which were peroxidized. These changes were less pronounced in treated ROS membranes; as an example in the presence of 10 mm melatonin or 2 mm N-acetylserotonin we observed a content preservation of 22:6 n-3 (23.6 +/- 1.2 and 39.1 +/- 1.2% respectively). The concentration of each compound required to inhibit 50% of the lipid peroxidation (IC50) was 9.82 mm for melatonin and 0.43 mm for N-acetylserotonin, respectively. N-acetylserotonin shows a protective effect about 20 times higher than that of melatonin.
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Affiliation(s)
- Margarita H Guajardo
- Cátedra de Bioquímica, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Argentina
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Ciuffi M, Pisanello M, Pagliai G, Raimondi L, Franchi-Micheli S, Cantore M, Mazzetti L, Failli P. Antioxidant protection in cultured corneal cells and whole corneas submitted to UV-B exposure. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2003; 71:59-68. [PMID: 14705640 DOI: 10.1016/j.jphotobiol.2003.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Several corneal pathologies are characterized by the presence of reactive oxygen species (ROS); therefore, we evaluated the protection afforded by pirenoxine and melatonin to corneal cell culture and whole rabbit cornea from ultraviolet exposure and other oxidant systems. Rabbit cornea cell (SIRC) plates and whole corneas were exposed to UV-B (80 or 800 mJ/cm2) or incubated with fMLP-stimulated autologous macrophages, in the presence or absence of pirenoxine or melatonin (10(-5) M). The protective activity of compounds was assessed by measuring superoxide anion formation, inhibition of oxidation and mitochondrial viability. Moreover the ex vivo protective effect of pirenoxine and melatonin was verified in the whole cornea submitted to UV-B exposure in vitro. Our experimental data demonstrate that pirenoxine and melatonin were able to inhibit the superoxide formation and oxidative effect in cell culture and whole rabbit corneas submitted to UV-B exposure or to incubation with fMLP-stimulated autologous macrophages. Mitochondrial viability was restored in epithelial cells of rabbit cornea but not in SIRCs. Moreover, both compounds are also able to increase ex vivo epithelial corneal cell defences against the in vitro UV-B induced lipid peroxidation.
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Affiliation(s)
- Mario Ciuffi
- Department of Preclinical and Clinical Pharmacology, University of Florence, V.le Pieraccini 6, Florence 50139, Italy.
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Kładna A, Aboul-Enein HY, Kruk I. Enhancing effect of melatonin on chemiluminescence accompanying decomposition of hydrogen peroxide in the presence of copper. Free Radic Biol Med 2003; 34:1544-54. [PMID: 12788474 DOI: 10.1016/s0891-5849(03)00180-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The oxidation of melatonin (MEL) using the Cu(II) + H(2)O(2) + HO(-) (the Fenton-like reaction) system was investigated by chemiluminescence (CL), fluorescence, spectrophotometric, and EPR spin trapping techniques. The reaction exhibits CL in the 400-730 nm region. The light emission from the Fenton-like reaction was greatly enhanced in the presence of MEL and was strongly dependent on its concentration. The spectrum measured with cut-off filters revealed maxima at around 460, 500, 580-590, 640-650, and 690-700 nm. The band at 460 nm may be due to the excited cleavage product, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine, whereas the bands at 500, 580-590, 640-650, and 700 nm were similar to those observed for singlet molecular oxygen ((1)O(2)). The effect of reactive oxygen species (ROS) scavengers on the light emission was studied. The CL was strongly inhibited by the (1)O(2) scavengers in a dose-dependent manner; at concentration 1 mM the potency of (1)O(2) scavenging was 5,5-dimethylcyclohexandione-1,3 > methionine > histidine > hydroquinone. The potency of HO(*) scavenging by thiourea, tryptophan, cysteine at concentration 5 mM was 79-94%, by 1 mM glutathione and trolox 75 and 94%, respectively, and by 10 mM cimetidine 18%. Specific acceptors of O(2)(*)(-) such as p-nitroblue tetrazolium chloride and 4,5-dihydroxy-1,3-benzene disulfonic acid (tiron) at concentration 5 mM decreased the CL by 51 and 95%, respectively, whereas superoxide dismutase (SOD) does not reduce the emission at concentration 2.8 U/ml. At higher concentration SOD substantially enhanced the light emission. Addition of 1360 U/ml catalase and 100 microM desferrioxamine strongly inhibited CL (96 and 90%, respectively). The increased generation of (1)O(2) from the Cu/H(2)O(2) system in the presence of MEL was confirmed using the spectrophotometric method based on the bleaching of p-nitrosodimethylaniline and by trapping experiments with 2,2,6,6-tetramethylpiperidine (TEMP) and subsequent electron paramagnetic (EPR) spectroscopy. These findings suggest the increased production of reactive oxygen species (O(2)(*)(-), HO(*), (1)O(2)) from the Fenton-like reaction in the presence of MEL. This means that the hormone is not able to act as classical chain-breaking antioxidant even at low concentration, and may show clear prooxidant activity at higher concentrations. In addition, long-lived carbonyl product of the MEL transformation in the triplet state can also be toxic by transferring its energy to organelles and causing a photochemical process.
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Affiliation(s)
- Aleksandra Kładna
- Department of Medical History and Ethics, Pomeranian Medical Academy, Szczecin, Poland
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50
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Abstract
Several studies have established that melatonin synthesis occurs in the retina of vertebrates, including mammals. In mammals, a subpopulation of photoreceptors (probably the cones) synthesize melatonin. Melatonin synthesis in the retina is elevated at night and reduced during the day in a fashion similar to events in the pineal gland. Both the MT1 and MT2 melatonin receptors are present in the retina and retinal melatonin does not contribute to circulating levels, suggesting that retinal melatonin acts locally as a neurohormone and/or neuromodulator. Melatonin synthesis in the retina of mammals is under the control of a circadian oscillator, and circadian rhythms in melatonin synthesis and/or release have been described for several species of mammals. These rhythms are present in vivo, persist in vitro, are entrained by light and are temperature compensated. The cloning of the gene responsible for the synthesis of the enzyme arylalkylamine N-acetyltransferase (the key enzyme in the melatonin biosynthetic pathway) has allowed studies of the molecular mechanisms responsible for the generation of retinal melatonin rhythmicity. The present review focuses on the cellular and molecular mechanisms that regulate melatonin synthesis. In particular, we discuss how the photic environment and the circadian clock interact in determining melatonin levels, in addition to the role that melatonin plays in retinal physiology.
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Affiliation(s)
- G Tosini
- Neuroscience Institute and NSF Center for Behavioral Neuroscience, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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