1
|
Reiter RJ, Sharma RN, Manucha W, Rosales-Corral S, Almieda Chuffa LGD, Loh D, Luchetti F, Balduini W, Govitrapong P. Dysfunctional mitochondria in age-related neurodegeneration: Utility of melatonin as an antioxidant treatment. Ageing Res Rev 2024; 101:102480. [PMID: 39236857 DOI: 10.1016/j.arr.2024.102480] [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: 06/21/2024] [Revised: 08/18/2024] [Accepted: 08/28/2024] [Indexed: 09/07/2024]
Abstract
Mitochondria functionally degrade as neurons age. Degenerative changes cause inefficient oxidative phosphorylation (OXPHOS) and elevated electron leakage from the electron transport chain (ETC) promoting increased intramitochondrial generation of damaging reactive oxygen and reactive nitrogen species (ROS and RNS). The associated progressive accumulation of molecular damage causes an increasingly rapid decline in mitochondrial physiology contributing to aging. Melatonin, a multifunctional free radical scavenger and indirect antioxidant, is synthesized in the mitochondrial matrix of neurons. Melatonin reduces electron leakage from the ETC and elevates ATP production; it also detoxifies ROS/RNS and via the SIRT3/FOXO pathway it upregulates activities of superoxide dismutase 2 and glutathione peroxidase. Melatonin also influences glucose processing by neurons. In neurogenerative diseases, neurons often adopt Warburg-type metabolism which excludes pyruvate from the mitochondria causing reduced intramitochondrial acetyl coenzyme A production. Acetyl coenzyme A supports the citric acid cycle and OXPHOS. Additionally, acetyl coenzyme A is a required co-substrate for arylalkylamine-N-acetyl transferase, which rate limits melatonin synthesis; therefore, melatonin production is diminished in cells that experience Warburg-type metabolism making mitochondria more vulnerable to oxidative stress. Moreover, endogenously produced melatonin diminishes during aging, further increasing oxidative damage to mitochondrial components. More normal mitochondrial physiology is preserved in aging neurons with melatonin supplementation.
Collapse
Affiliation(s)
- Russel J Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, Long School of Medicine, San Antonio, TX, USA.
| | - Ramaswamy N Sharma
- Applied Biomedical Sciences, University of the Incarnate Word, School of Osteopathic Medicine, San Antonio, TX, USA.
| | - Walter Manucha
- Instituto de Medicina y Biologia Experimental de Cuyo (IMBECU), Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CONICET), Mendoza 5500, Argentina.
| | - Sergio Rosales-Corral
- Centro de Investigacion Biomedica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara, Mexico.
| | - Luiz Gustavo de Almieda Chuffa
- Departamento de Biologia Estrutural e Funcional, Setor de Anatomia - Instituto de Biociências, IBB/UNESP, Campus Botucatu, Botucatu, São Paulo, Brazil.
| | - Doris Loh
- Independent Researcher, Marble Falls, TX, USA.
| | - Francesca Luchetti
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy.
| | - Walter Balduini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy.
| | - Piyarat Govitrapong
- Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Laksi, Bangkok, Thailand.
| |
Collapse
|
2
|
Reiter RJ, Sharma R, Cucielo MS, Tan DX, Rosales-Corral S, Gancitano G, de Almeida Chuffa LG. Brain washing and neural health: role of age, sleep, and the cerebrospinal fluid melatonin rhythm. Cell Mol Life Sci 2023; 80:88. [PMID: 36917314 PMCID: PMC11072793 DOI: 10.1007/s00018-023-04736-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 02/02/2023] [Accepted: 02/24/2023] [Indexed: 03/16/2023]
Abstract
The brain lacks a classic lymphatic drainage system. How it is cleansed of damaged proteins, cellular debris, and molecular by-products has remained a mystery for decades. Recent discoveries have identified a hybrid system that includes cerebrospinal fluid (CSF)-filled perivascular spaces and classic lymph vessels in the dural covering of the brain and spinal cord that functionally cooperate to remove toxic and non-functional trash from the brain. These two components functioning together are referred to as the glymphatic system. We propose that the high levels of melatonin secreted by the pineal gland directly into the CSF play a role in flushing pathological molecules such as amyloid-β peptide (Aβ) from the brain via this network. Melatonin is a sleep-promoting agent, with waste clearance from the CNS being highest especially during slow wave sleep. Melatonin is also a potent and versatile antioxidant that prevents neural accumulation of oxidatively-damaged molecules which contribute to neurological decline. Due to its feedback actions on the suprachiasmatic nucleus, CSF melatonin rhythm functions to maintain optimal circadian rhythmicity, which is also critical for preserving neurocognitive health. Melatonin levels drop dramatically in the frail aged, potentially contributing to neurological failure and dementia. Melatonin supplementation in animal models of Alzheimer's disease (AD) defers Aβ accumulation, enhances its clearance from the CNS, and prolongs animal survival. In AD patients, preliminary data show that melatonin use reduces neurobehavioral signs such as sundowning. Finally, melatonin controls the mitotic activity of neural stem cells in the subventricular zone, suggesting its involvement in neuronal renewal.
Collapse
Affiliation(s)
- Russel J Reiter
- Department of Cell Systems and Anatomy, Long School of Medicine, UT Health San Antonio, San Antonio, TX, 78229, USA.
| | - Ramaswamy Sharma
- Department of Cell Systems and Anatomy, Long School of Medicine, UT Health San Antonio, San Antonio, TX, 78229, USA.
| | - Maira Smaniotto Cucielo
- Department of Structural and Functional Biology-IBB/UNESP, Institute of Biosciences of Botucatu, Universidade Estadual Paulista, Botucatu, São Paulo, 18618-689, Brazil
| | | | - Sergio Rosales-Corral
- Centro de Investigacion Biomedica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara, Mexico
| | - Giuseppe Gancitano
- 1st "Tuscania" Paratrooper Regiment, Italian Ministry of Defense, 57127, Leghorn, Italy
| | - Luiz Gustavo de Almeida Chuffa
- Department of Structural and Functional Biology-IBB/UNESP, Institute of Biosciences of Botucatu, Universidade Estadual Paulista, Botucatu, São Paulo, 18618-689, Brazil
| |
Collapse
|
3
|
Melatonin in ventricular and subarachnoid cerebrospinal fluid: Its function in the neural glymphatic network and biological significance for neurocognitive health. Biochem Biophys Res Commun 2022; 605:70-81. [DOI: 10.1016/j.bbrc.2022.03.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 12/13/2022]
|
4
|
Cardinali DP, Brown GM, Pandi-Perumal SR. Melatonin's Benefits and Risks as a Therapy for Sleep Disturbances in the Elderly: Current Insights. Nat Sci Sleep 2022; 14:1843-1855. [PMID: 36267165 PMCID: PMC9578490 DOI: 10.2147/nss.s380465] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/03/2022] [Indexed: 01/19/2023] Open
Abstract
Aging is accompanied by circadian changes, including disruptive alterations in the sleep/wake cycle, as well as the beginning of low-degree inflammation ("inflammaging"), a scenario that leads to several chronic illnesses, including cancer, and metabolic, cardiovascular, and neurological dysfunctions. As a result, any effective approach to healthy aging must consider both the correction of circadian disturbance and the control of low-grade inflammation. One of the most important prerequisites for healthy aging is the preservation of robust circadian rhythmicity (particularly of the sleep/wake cycle). Sleep disturbance disrupts various activities in the central nervous system, including waste molecule elimination. Melatonin is a chemical with extraordinary phylogenetic conservation found in all known aerobic creatures whose alteration plays an important role in sleep changes with aging. Every day, the late afternoon/nocturnal surge in pineal melatonin helps to synchronize both the central circadian pacemaker found in the hypothalamic suprachiasmatic nuclei (SCN) and a plethora of peripheral cellular circadian clocks. Melatonin is an example of an endogenous chronobiotic substance that can influence the timing and amplitude of circadian rhythms. Moreover, melatonin is also an excellent anti-inflammatory agent, buffering free radicals, down-regulating proinflammatory cytokines, and reducing insulin resistance, among other things. We present both scientific and clinical evidence that melatonin is a safe drug for treating sleep disturbances in the elderly.
Collapse
Affiliation(s)
- Daniel P Cardinali
- Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, Buenos Aires, Argentina
| | - Gregory M Brown
- Molecular Brain Science Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | | |
Collapse
|
5
|
Melhuish Beaupre LM, Brown GM, Gonçalves VF, Kennedy JL. Melatonin's neuroprotective role in mitochondria and its potential as a biomarker in aging, cognition and psychiatric disorders. Transl Psychiatry 2021; 11:339. [PMID: 34078880 PMCID: PMC8172874 DOI: 10.1038/s41398-021-01464-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 04/16/2021] [Accepted: 05/14/2021] [Indexed: 02/05/2023] Open
Abstract
Melatonin is an ancient molecule that is evident in high concentrations in various tissues throughout the body. It can be separated into two pools; one of which is synthesized by the pineal and can be found in blood, and the second by various tissues and is present in these tissues. Pineal melatonin levels display a circadian rhythm while tissue melatonin does not. For decades now, melatonin has been implicated in promoting and maintaining sleep. More recently, evidence indicates that it also plays an important role in neuroprotection. The beginning of our review will summarize this literature. As an amphiphilic, pleiotropic indoleamine, melatonin has both direct actions and receptor-mediated effects. For example, melatonin has established effects as an antioxidant and free radical scavenger both in vitro and in animal models. This is also evident in melatonin's prominent role in mitochondria, which is reviewed in the next section. Melatonin is synthesized in, taken up by, and concentrated in mitochondria, the powerhouse of the cell. Mitochondria are also the major source of reactive oxygen species as a byproduct of mitochondrial oxidative metabolism. The final section of our review summarizes melatonin's potential role in aging and psychiatric disorders. Pineal and tissue melatonin levels both decline with age. Pineal melatonin declines in individuals suffering from psychiatric disorders. Melatonin's ability to act as a neuroprotectant opens new avenues of exploration for the molecule as it may be a potential treatment for cases with neurodegenerative disease.
Collapse
Affiliation(s)
- Lindsay M Melhuish Beaupre
- Molecular Brain Science Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Gregory M Brown
- Molecular Brain Science Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Vanessa F Gonçalves
- Molecular Brain Science Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - James L Kennedy
- Molecular Brain Science Research Department, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
6
|
Zhao F, Ma C, Zhao G, Wang G, Li X, Yang K. Rumen-Protected 5-Hydroxytryptophan Improves Sheep Melatonin Synthesis in the Pineal Gland and Intestinal Tract. Med Sci Monit 2019; 25:3605-3616. [PMID: 31091223 PMCID: PMC6534969 DOI: 10.12659/msm.915909] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Based on the extensive biological effects of melatonin (MLT), it is beneficial to increase the MLT content in the bodies of animals at a specific physiological stage. This study was conducted to investigate the effect of a diet supplemented with rumen-protected (RP) 5-hydroxytryptophan (5-HTP) on the pineal gland and intestinal tract MLT synthesis of sheep. MATERIAL AND METHODS Eighteen Kazakh sheep were assigned randomly to 3 diet groups: control group (CT, corn-soybean meal basal diet), CT+111 group (111 mg/kg BW RP 5-HTP), and CT+222 group (222 mg/kg BW RP 5-HTP). The gene expressions of aromatic amino acid decarboxylase (AADC), arylalkylamine N-acetyltransferase (AA-NAT), hydroxyindole-O-methyltransferase (HIOMT), monoamine oxidase A (MAOA), and the intermediates of MLT synthesis were observed from the pineal gland and intestinal tract by the reverse transcription (RT)-PCR method. The 5-HTP, 5-HT, N-acetylserotonin (NAS), MLT, and 5-hydroxyindole acetic acid (5-HIAA) contents in the pineal gland and intestinal tract were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry. RESULTS The study showed that the pineal gland HIOMT expression (P<0.05), MLT (P<0.05) and 5-HIAA (P<0.05) levels in the 222 mg/kg group significantly increased compared to those in the CT and CT+111 mg/kg groups. In addition, the AADC (P<0.01) and AA-NAT (P<0.05) gene expression levels in the duodenum and jejunum were increased by the supplementation of RP 5-HTP. CONCLUSIONS Rumen-protected 5-hydroxytryptophan promoted melatonin synthesis in the pineal gland and intestinal tract during the natural light period.
Collapse
Affiliation(s)
- Fang Zhao
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| | - Chen Ma
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| | - Guodong Zhao
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| | - Gen Wang
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| | - Xiaobin Li
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| | - Kailun Yang
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China (mainland)
| |
Collapse
|
7
|
Tan DX, Xu B, Zhou X, Reiter RJ. Pineal Calcification, Melatonin Production, Aging, Associated Health Consequences and Rejuvenation of the Pineal Gland. Molecules 2018; 23:E301. [PMID: 29385085 PMCID: PMC6017004 DOI: 10.3390/molecules23020301] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 01/24/2018] [Accepted: 01/26/2018] [Indexed: 01/26/2023] Open
Abstract
The pineal gland is a unique organ that synthesizes melatonin as the signaling molecule of natural photoperiodic environment and as a potent neuronal protective antioxidant. An intact and functional pineal gland is necessary for preserving optimal human health. Unfortunately, this gland has the highest calcification rate among all organs and tissues of the human body. Pineal calcification jeopardizes melatonin's synthetic capacity and is associated with a variety of neuronal diseases. In the current review, we summarized the potential mechanisms of how this process may occur under pathological conditions or during aging. We hypothesized that pineal calcification is an active process and resembles in some respects of bone formation. The mesenchymal stem cells and melatonin participate in this process. Finally, we suggest that preservation of pineal health can be achieved by retarding its premature calcification or even rejuvenating the calcified gland.
Collapse
Affiliation(s)
- Dun Xian Tan
- Department of Cell Systems & Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA.
| | - Bing Xu
- Department of Cell Systems & Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA.
| | - Xinjia Zhou
- Department of Cell Systems & Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA.
| | - Russel J Reiter
- Department of Cell Systems & Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA.
| |
Collapse
|
8
|
Markus RP, Fernandes PA, Kinker GS, da Silveira Cruz-Machado S, Marçola M. Immune-pineal axis - acute inflammatory responses coordinate melatonin synthesis by pinealocytes and phagocytes. Br J Pharmacol 2017; 175:3239-3250. [PMID: 29105727 DOI: 10.1111/bph.14083] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/21/2017] [Accepted: 09/20/2017] [Indexed: 12/12/2022] Open
Abstract
Melatonin is well known for its circadian production by the pineal gland, and there is a growing body of data showing that it is also produced by many other cells and organs, including immune cells. The chronobiotic role of pineal melatonin, as well as its protective effects in vitro and in vivo, have been extensively explored. However, the interaction between the chronobiotic and defence functions of endogenous melatonin has been little investigated. This review details the current knowledge regarding the coordinated shift in melatonin synthesis from the pineal gland (circadian and monitoring roles) to the regulation of acute immune responses via immune cell production and autocrine effects, producing systemic interactions termed the immune-pineal axis. An acute inflammatory response drives the transcription factor, NFκB, to switch melatonin synthesis from pinealocytes to macrophages/microglia and, upon acute inflammatory resolution, back to pinealocytes. The potential pathophysiological relevance of immune-pineal axis dysregulation is highlighted, with both research and clinical implications, across several medical conditions, including host/parasite interaction, neurodegenerative diseases and cancer. LINKED ARTICLES: This article is part of a themed section on Recent Developments in Research of Melatonin and its Potential Therapeutic Applications. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.16/issuetoc.
Collapse
Affiliation(s)
- Regina P Markus
- Laboratory of Chronopharmacology and Laboratory of Neuroimmunomodulation - Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | - Pedro A Fernandes
- Laboratory of Chronopharmacology and Laboratory of Neuroimmunomodulation - Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | - Gabriela S Kinker
- Laboratory of Chronopharmacology and Laboratory of Neuroimmunomodulation - Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | - Sanseray da Silveira Cruz-Machado
- Laboratory of Chronopharmacology and Laboratory of Neuroimmunomodulation - Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| | - Marina Marçola
- Laboratory of Chronopharmacology and Laboratory of Neuroimmunomodulation - Department of Physiology, Institute of Bioscience, University of São Paulo, São Paulo, Brazil
| |
Collapse
|
9
|
Roguski A, Gill AC. The Role of the Mammalian Prion Protein in the Control of Sleep. Pathogens 2017; 6:pathogens6040058. [PMID: 29149024 PMCID: PMC5750582 DOI: 10.3390/pathogens6040058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/08/2017] [Accepted: 11/13/2017] [Indexed: 01/09/2023] Open
Abstract
Sleep disruption is a prevalent clinical feature in many neurodegenerative disorders, including human prion diseases where it can be the defining dysfunction, as in the case of the "eponymous" fatal familial insomnia, or an early-stage symptom as in certain types of Creutzfeldt-Jakob disease. It is important to establish the role of the cellular prion protein (PrPC), the key molecule involved in prion pathogenesis, within the sleep-wake system in order to understand fully the mechanisms underlying its contribution to both healthy circadian rhythmicity and sleep dysfunction during disease. Although severe disruption to the circadian rhythm and melatonin release is evident during the pathogenic phases of some prion diseases, untangling whether PrPC plays a role in circadian rhythmicity, as suggested in mice deficient for PrPC expression, is challenging given the lack of basic experimental research. We provide a short review of the small amount of direct literature focused on the role of PrPC in melatonin and circadian rhythm regulation, as well as suggesting mechanisms by which PrPC might exert influence upon noradrenergic and dopaminergic signaling and melatonin synthesis. Future research in this area should focus upon isolating the points of dysfunction within the retino-pineal pathway and further investigate PrPC mediation of pinealocyte GPCR activity.
Collapse
Affiliation(s)
- Amber Roguski
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
| | - Andrew C Gill
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Green Lane, Lincoln, Lincolnshire LN6 7DL, UK.
| |
Collapse
|
10
|
Melatoninergic System in Parkinson's Disease: From Neuroprotection to the Management of Motor and Nonmotor Symptoms. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:3472032. [PMID: 27829983 PMCID: PMC5088323 DOI: 10.1155/2016/3472032] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/25/2016] [Indexed: 12/13/2022]
Abstract
Melatonin is synthesized by several tissues besides the pineal gland, and beyond its regulatory effects in light-dark cycle, melatonin is a hormone with neuroprotective, anti-inflammatory, and antioxidant properties. Melatonin acts as a free-radical scavenger, reducing reactive species and improving mitochondrial homeostasis. Melatonin also regulates the expression of neurotrophins that are involved in the survival of dopaminergic neurons and reduces α-synuclein aggregation, thus protecting the dopaminergic system against damage. The unbalance of pineal melatonin synthesis can predispose the organism to inflammatory and neurodegenerative diseases such as Parkinson's disease (PD). The aim of this review is to summarize the knowledge about the potential role of the melatoninergic system in the pathogenesis and treatment of PD. The literature reviewed here indicates that PD is associated with impaired brain expression of melatonin and its receptors MT1 and MT2. Exogenous melatonin treatment presented an outstanding neuroprotective effect in animal models of PD induced by different toxins, such as 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, paraquat, and maneb. Despite the neuroprotective effects and the improvement of motor impairments, melatonin also presents the potential to improve nonmotor symptoms commonly experienced by PD patients such as sleep and anxiety disorders, depression, and memory dysfunction.
Collapse
|