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Geneva II. The circadian rhythm of human body temperature - Clinical implications and review of the literature. Chronobiol Int 2025:1-14. [PMID: 40433988 DOI: 10.1080/07420528.2025.2511268] [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: 11/08/2024] [Revised: 04/15/2025] [Accepted: 05/20/2025] [Indexed: 05/29/2025]
Abstract
Human body temperature remains an essential vital sign that had been used to judge our health given its strong correlation with human disease. Body temperature is also a manifestation of our circadian rhythm, with a predictable rise during the day peaking in the evenings and steady decrease during the night reaching a minimum around the time of awakening. Yet, the rhythm is believed to be endogenous and to exist independently of any external stimuli, including day light. Human illnesses such as infections, autoimmune conditions, and cancer had been associated with a disruption in the circadian rhythm. This is of significant clinical interest because measurements of the specific disruptions of the rhythm appear to carry diagnostic and prognostic value. This is a review of the literature with a focus on the determinants of human body temperature and the circadian rhythm of body temperature. The last section provides potential new research avenues in our search for chronotherapy clinical applications.
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Charif SE, Inserra PIF, Villarreal FM, Schmidt AR, Cortasa SA, Proietto S, Corso MC, Llanos Dumont MI, Di Giorgio NP, Halperin J, Vitullo AD, Dorfman VB. Light/darkness modulation of the hypothalamic-pituitary-ovarian axis in the plains vizcacha, Lagostomus maximus, a seasonal breeding species. Gen Comp Endocrinol 2025; 366:114714. [PMID: 40139328 DOI: 10.1016/j.ygcen.2025.114714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 03/07/2025] [Accepted: 03/21/2025] [Indexed: 03/29/2025]
Abstract
Photoperiod is the main environmental signal that affects animal behavior and reproduction. Light stimulus is traduced by a neural pathway that modulates pineal gland melatonin release, which synchronizes physiologic functions with day duration, highly influencing seasonal reproduction. The plains vizcacha (Lagostomus maximus) is a Hystricomorph rodent with seasonal reproduction that inhabits the Neotropic in South America. The aim of this work was to elucidate the effect of light/darkness exposition on the reproductive hypothalamic-pituitary-ovarian (HPO) axis in the female plains vizcacha. During 15 days, animals were subjected to different light/darkness regimens (Control group, CTL: 12:12 h dark:light; Darkness group, DARK: continuous darkness; Light group, LIGHT: continuous light). The melatoninergic system and reproductive hormones were evaluated. Plasma melatonin levels significantly decreased in DARK whereas both melatonin receptors (MT1 and MT2) expression significantly increased in the hypothalamus and decreased in the pituitary gland, and only MT1 expression increased in the ovaries. Continuous light did not induce significant variations in melatonin levels related to CTL, however, MTs expression changed at pituitary and ovary levels. Strikingly, both light/darkness regimens increased reproductive hormone expression. While darkness induced hypothalamic gonadotropin-releasing hormone (GnRH) expression and estradiol (E2) secretion, light increased LH and progesterone (P4) secretion. In conclusion, light availability may impact the reproductive axis of plains vizcacha inducing hormonal changes, with an organ-specific response, and sustaining HPO axis activity, thus ensuring reproduction. Environmental light and darkness, their availability and exposure length, could synchronize the reproductive axis in seasonal breeding species like the plains vizcacha. New & Noteworthy: Hypothalamic, pituitary, and ovarian variations were induced by continuous light or darkness in the plains vizcacha. Plasma melatonin decreased by continuous darkness-inducing hypothalamic, pituitary, and ovarian melatonin receptors variations. Fifteen days of continuous darkness induced GnRH, LH, and estradiol secretion, while 15 days of continuous light induced LH and P4 secretion. Environmental light/darkness would synchronize the reproductive axis in seasonal breeding species like the plains vizcacha.
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Affiliation(s)
- Santiago Elías Charif
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; Technology Institute (INTEC), Universidad Argentina de la Empresa (UADE), Ciudad Autónoma de Buenos Aires, Argentina.
| | - Pablo Ignacio Felipe Inserra
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Federico Martín Villarreal
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Alejandro Raúl Schmidt
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Santiago Andrés Cortasa
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Sofía Proietto
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - María Clara Corso
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Micaela Inés Llanos Dumont
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina
| | - Noelia Paula Di Giorgio
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IByME) - CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julia Halperin
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Alfredo Daniel Vitullo
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Verónica Berta Dorfman
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
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Song Y, Yoon M. Melatonin effects on animal behavior: circadian rhythm, stress response, and modulation of behavioral patterns. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2025; 67:1-16. [PMID: 39974791 PMCID: PMC11833209 DOI: 10.5187/jast.2024.e105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 09/26/2024] [Accepted: 10/29/2024] [Indexed: 02/21/2025]
Abstract
Melatonin plays a crucial role in various behavioral and physiological aspects of animals, including regulating their circadian rhythms. This review provides a comprehensive evaluation of the multifaceted effects of melatonin on animal behavior, such as temperament, stress, and aggression regulation. The focus is on the complex interactions between melatonin and the hormonal and neurotransmitter systems, highlighting how melatonin interacts with cortisol, serotonin, and dopamine to influence behavior. Additionally, it investigates the effects of melatonin on the hypothalamic-pituitary-gonada (HPG) axis and stress responses, emphasizing its potential to improve stress management and social interactions, thereby enhancing animal welfare. The review also examines the seasonal variations of melatonin and its impact on aggression and reproductive activities related to photoperiods, as well as its effects on learning and memory to suggest improvements in animal training methods and practices. Furthermore, it discusses the influence of melatonin on appetite and physical activity regulation, implying its involvement in metabolic processes. In conclusion, further research is needed to elucidate the complex mechanisms underlying the extensive influence of melatonin on animal behavior. Through this review, the aim is to integrate the overall knowledge about melatonin and animal behavioral temperament and to propose new research areas for animal management based on behavioral and hormonal regulation.
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Affiliation(s)
- Yubin Song
- Department of Animal Science and
Biotechnology, Kyungpook National University, Sangju 37224,
Korea
| | - Minjung Yoon
- Department of Animal Science and
Biotechnology, Kyungpook National University, Sangju 37224,
Korea
- Department of Horse, Companion and Wild
Animal Science, Kyungpook National University, Sangju 37224,
Korea
- Research Institute for Innovative Animal
Science, Kyungpook National University, Sangju 37224,
Korea
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Shankey NT, Igo BL, Grossen TL, Cohen RE. Melatonin treatment during the breeding season increases testosterone in male green anole lizards (Anolis carolinensis). Horm Behav 2024; 166:105655. [PMID: 39522144 DOI: 10.1016/j.yhbeh.2024.105655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 10/18/2024] [Accepted: 10/23/2024] [Indexed: 11/16/2024]
Abstract
Melatonin is a natural hormone that regulates seasonal behaviors in vertebrates by binding to its receptors (MT1 and MT2). Specifically, high levels of melatonin are associated with short photoperiods, often coinciding with the non-breeding season, meaning that melatonin may inhibit seasonal reproduction. Green anole lizards (Anolis carolinensis), have large, active gonads, increased levels of testosterone and estradiol, and increased reproductive behaviors during the breeding season. Previous studies have examined the role of melatonin in seasonal reproduction in this species, but it is unclear how melatonin receptors change seasonally or if melatonin treatment during the early breeding season influences reproduction. In Experiment 1, we measured MT1 and MT2 mRNA expression in the brains and gonads of unmanipulated anoles between breeding and non-breeding seasons. MT1 mRNA expression was significantly higher in the male brain during the breeding season compared to the non-breeding season, and MT1 mRNA levels were generally higher compared to MT2. This suggests that melatonin may regulate seasonal reproduction through MT1 in the brain, and higher levels during the breeding season may compensate for low seasonal levels of melatonin. In Experiment 2, anoles were treated with melatonin or a blank control for 10 weeks during the breeding season. In males, melatonin treatment increased testosterone levels. This suggests that rather than inhibiting reproduction, continuous high doses of melatonin may increase reproductive hormones during the breeding season. Our findings support the role of melatonin in modulating seasonal reproduction, but the exact mechanisms behind melatonin's stimulatory effect is unclear.
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Affiliation(s)
- Nicholas T Shankey
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, MN 56001-6062, USA
| | - Bernadette L Igo
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, MN 56001-6062, USA
| | - Taylor L Grossen
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, MN 56001-6062, USA
| | - Rachel E Cohen
- Department of Biological Sciences, Minnesota State University, Mankato, Mankato, MN 56001-6062, USA.
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Charif SE, Dorfman VB. Melatonin, modulation of hypothalamic activity, and reproduction. VITAMINS AND HORMONES 2024; 127:283-303. [PMID: 39864944 DOI: 10.1016/bs.vh.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2025]
Abstract
Light is the most reliable environmental cue allowing animals to breed successfully when conditions are optimal. In seasonal breeders, photoperiod (length of daylight) information is sensed by the eyes and transmitted to the suprachiasmatic nucleus, the master clock region located in the hypothalamus. This structure has a 24-h firing rhythm involving a cycle of clock protein synthesis and degradation, and provides the timing to synchronize the synthesis and release of melatonin, the chemical signal that transduces the photoperiod information. The enzyme arylalkylamine N-acetyltransferase, responsible for melatonin synthesis in the pineal gland, is modulated by environmental light. Melatonin is secreted during the dark hours of the night to blood circulation and cerebrospinal fluid conveying photoperiod information to other tissues. Melatonin exerts its action by binding to specific membrane receptors MT1 and MT2, and can modulate several pathways including neurotransmitters, and hormones like kisspeptin, the gonadotropin-inhibitory hormone, and thyroid hormones, all of them impacting on gonadotropin-releasing hormone (GnRH) secretion. Then, GnRH will modulate in turn the reproductive axis. In conclusion, acting as a transducer of photoperiod information, this hormone exerts precisely timed activation of different pathways that modulate seasonal breeding ensuring optimal conditions for reproduction.
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Affiliation(s)
- Santiago Elías Charif
- Instituto de Tecnología (INTEC), Universidad Argentina de la Empresa (UADE), Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Verónica Berta Dorfman
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina; Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina.
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Klosen P. Thirty-seven years of MT1 and MT2 melatonin receptor localization in the brain: Past and future challenges. J Pineal Res 2024; 76:e12955. [PMID: 38606787 DOI: 10.1111/jpi.12955] [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: 10/26/2023] [Revised: 02/21/2024] [Accepted: 03/31/2024] [Indexed: 04/13/2024]
Abstract
Identifying the target cells of a hormone is a key step in understanding its function. Once the molecular nature of the receptors for a hormone has been established, researchers can use several techniques to detect these receptors. Here I will review the different tools used over the years to localize melatonin receptors and the problems associated with each of these techniques. The radioligand 2-[125I] iodomelatonin was the first tool to allow localization of melatonin receptors on tissue sections. Once the MT1 and MT2 receptors were cloned, in situ hybridization could be used to detect the messenger RNA for these receptors. The deduced amino acid sequences for MT1 and MT2 receptors allowed the production of peptide immunogens to generate antibodies against the MT1 and MT2 receptors. Finally, transgenic reporters driven by the promoter elements of the MT1 and MT2 genes have been used to map the expression of MT1 and MT2 in the brain and the retina. Several issues have complicated the localization of melatonin receptors and the characterization of melatonin target cells over the last three decades. Melatonin receptors are expressed at low levels, leading to sensitivity issues for their detection. The second problem are specificity issues with antibodies directed against the MT1 and MT2 melatonin receptors. These receptors are G protein-coupled receptors and many antibodies directed against such receptors have been shown to present similar problems concerning their specificity. Despite these specificity problems which start to be seriously addressed by recent studies, antibodies will be important tools in the future to identify and phenotype melatonin target cells. However, we will have to be more stringent than previously when establishing their specificity. The results obtained by these antibodies will have to be confronted and be coherent with results obtained by other techniques.
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Affiliation(s)
- Paul Klosen
- Regulation and Disruption of Neuroendocrine Rhythms, Institute of Cellular and Integrative Neurosciences, INCI CNRS UPR-3212, University of Strasbourg, Strasbourg, France
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SUN Y, XUE Y, SUN W, WANG Y, YU J. Effect of nourishing and purging fire Chinese herbal mixture on delaying light-induced premature puberty in rats. J TRADIT CHIN MED 2024; 44:95-102. [PMID: 38213244 PMCID: PMC10774740 DOI: 10.19852/j.cnki.jtcm.20230814.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/15/2022] [Indexed: 01/13/2024]
Abstract
OBJECTIVE To elucidate the mechanism of the nourishing Yin and purging fire Chinese herbal mixture (NYPF) in delaying light-induced premature puberty in rats. METHODS Twenty-one days old female Sprague-Dawley rats were randomly assigned to normal group (N), long light exposure group (L), NYPF and normal saline group (NS). Rats in the L, NYPF and NS groups were exposed to 16 h: 350 lux light/8 h: dark, while rats in the N group were exposed to 12 h: 50 lux light/12 h: dark. NYPF and normal saline was administered to the rats in the NYPF group or NS group, respectively, from day 21. Five rats in every group were sacrificed at 9 p.m. on day 28 (P28), on the day when rat's vulva opened in the L group (L-VO), on the day when the first estrous interphase occurred in rats of L group (L-E1), and on the day when the second estrous interphase occurred in rats of L group (L-E2), respectively. RESULITS On day 34, all rats in the L group, 80% of rats in the NS group, 40% of rats in the N group, and 20% of rats in the NYPF group showed complete opening of the vulva. At P28, mRNA level of hypothalamic kisspeptin (Kiss-1) in the L group was significantly higher than that in the N group (P < 0.05). The rats in the L and NS groups had significantly lower hypothalamic arginine-phenylalanine-amide (RFamide)-related peptide 3 (RFRP-3) mRNA levels than those in the N group (P < 0.05), whereas RFRP-3 mRNA level was significantly higher in the NYPF group than that in the L group (P < 0.05). At L-VO, the ovarian index of the L and NS groups was significantly higher than that of the N group (P < 0.05) and estradiol (E2) level of the NYPF group was significantly lower than that of the N and NS groups (P < 0.05); hypothalamic Kiss-1 mRNA level in the L and NS groups was significantly higher than that in the N and NYPF groups (P < 0.05), whereas hypothalamic RFRP-3 mRNA level in the L, NYPF, and NS groups was significantly lower than that in the N group (P < 0.05). At L-E1, E2 level of the L and NS groups was significantly higher than that of the N group (P < 0.01), whereas it was significantly lower in the NYPF group than that of the N, L, and NS groups (P < 0.01), and serum luteinizing hormone level of the L and NS groups was significantly higher than that of the N group (P < 0.05); levels of serum melatonin and ovarian melatonin receptor 1 (MT-1) mRNA in the L, NYPF, and NS groups were significantly lower than those in the N group (P < 0.05). At L-E2, the uterine organ index of the NYPF group was significantly lower than that of the L group (P < 0.05); and ovarian MT-1 mRNA level of the L and NS groups was significantly lower than that in the N group (P < 0.05). CONCLUSIONS NYPF can delay puberty onset in rats exposed to strong light for a prolonged duration, and regulation of the gene expression of Kiss-1 and RFRP-3 in the hypothalamus has been suggested as one of the mechanisms.
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Affiliation(s)
- Yanyan SUN
- 1 Department of Traditional Chinese Medicine, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Yuanyuan XUE
- 2 Department of Pediatrics, Zibo Central Hospital, Zibo 255000, China
| | - Wen SUN
- 1 Department of Traditional Chinese Medicine, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Yonghong WANG
- 1 Department of Traditional Chinese Medicine, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Jian YU
- 1 Department of Traditional Chinese Medicine, Children's Hospital of Fudan University, Shanghai 201102, China
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Zhu H, Wu M, Mou J, Yang X, Xu Q, Zhang Y, Zhang H, Wang X, Xue H, Xu J, Chen L, Xu L. Behavior and physiology in female Cricetulus barabensis are associated with the expression of circadian genes. Front Endocrinol (Lausanne) 2024; 14:1281617. [PMID: 38374960 PMCID: PMC10875996 DOI: 10.3389/fendo.2023.1281617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/08/2023] [Indexed: 02/21/2024] Open
Abstract
The circadian clock regulates the behavior, physiology, and metabolism of mammals, and these characteristics, such as sleep-wake cycles, exercise capacity, and hormone levels, exhibit circadian rhythms. Light signaling is the main stimulator of the mammalian circadian system. The photoperiod regulates the reproductive cycle of seasonal breeding animals, and the circadian clock plays a pivotal role in this process. However, the role of the clock in coordinating animal behavior and physiology in response to photoperiodic changes needs further investigation. The present study investigated the changes and correlation of behavioral activities, physiological indicators, and gene expression in female striped hamsters (Cricetulus barabensis) within 24 h under a 12L:12D photoperiod. We found that the daily rhythms of sleep-wake and open field were significant in hamsters. The expression of clock genes, melatonin receptor genes, and genes involved in general metabolism oscillated significantly in central and peripheral tissues (brain, hypothalamus, liver, ovary, and thymus) and was significantly associated with behavior and physiology. Our results revealed that the neuroendocrine system regulated the rhythmicity of behavior and physiology, and central and peripheral clock genes (Bmal1, Clock, Per1, Per2, Cry1, and Cry2), melatonin receptor genes (MT1, MT2, and GPR50), and metabolizing genes (SIRT1, FGF21, and PPARα) played important roles. Our results suggest that central and peripheral circadian clocks, melatonin receptors, and genes involved in general metabolism may play key roles in maintaining circadian behavior and metabolic homeostasis in striped hamsters. Our results may have important implication for rodent pest control.
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Feng Y, Jiang X, Liu W, Lu H. The location, physiology, pathology of hippocampus Melatonin MT 2 receptor and MT 2-selective modulators. Eur J Med Chem 2023; 262:115888. [PMID: 37866336 DOI: 10.1016/j.ejmech.2023.115888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 10/24/2023]
Abstract
Melatonin, a neurohormone secreted by the pineal gland and regulated by the suprachiasmatic nucleus (SCN) of the hypothalamus, is synthesized and directly released into the cerebrospinal fluid (CSF) of the third ventricle (3rdv), where it undergoes rapid absorption by surrounding tissues to exert its physiological function. The hippocampus, a vital structure in the limbic system adjacent to the ventricles, plays a pivotal role in emotional response and memory formation. Melatonin MT1 and MT2 receptors are G protein-coupled receptors (GPCRs) that primarily mediate melatonin's receptor-dependent effects. In comparison to the MT1 receptor, the widely expressed MT2 receptor is crucial for mediating melatonin's biological functions within the hippocampus. Specifically, MT2 receptor is implicated in hippocampal synaptic plasticity and memory processes, as well as neurogenesis and axogenesis. Numerous studies have demonstrated the involvement of MT2 receptors in the pathophysiology and pharmacology of Alzheimer's disease, depression, and epilepsy. This review focuses on the anatomical localization of MT2 receptor in the hippocampus, their physiological function in this region, and their signal transduction and pharmacological roles in neurological disorders. Additionally, we conducted a comprehensive review of MT2 receptor ligands used in psychopharmacology and other MT2-selective ligands over recent years. Ultimately, we provide an outlook on future research for selective MT2 receptor drug candidates.
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Affiliation(s)
- Yueqin Feng
- Department of Ultrasound, the First Affiliated Hospital of China Medical University, Shenyang, PR China
| | - Xiaowen Jiang
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Wenwu Liu
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, PR China
| | - Hongyuan Lu
- Department of Clinical Pharmacology, China Medical University, Shenyang, PR China.
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Xie L, Wu H, Huang X, Yu T. Melatonin, a natural antioxidant therapy in spinal cord injury. Front Cell Dev Biol 2023; 11:1218553. [PMID: 37691830 PMCID: PMC10485268 DOI: 10.3389/fcell.2023.1218553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 08/11/2023] [Indexed: 09/12/2023] Open
Abstract
Spinal cord injury (SCI) is a sudden onset of disruption to the spinal neural tissue, leading to loss of motor control and sensory function of the body. Oxidative stress is considered a hallmark in SCI followed by a series of events, including inflammation and cellular apoptosis. Melatonin was originally discovered as a hormone produced by the pineal gland. The subcellular localization of melatonin has been identified in mitochondria, exhibiting specific onsite protection to excess mitochondrial reactive oxygen species and working as an antioxidant in diseases. The recent discovery regarding the molecular basis of ligand selectivity for melatonin receptors and the constant efforts on finding synthetic melatonin alternatives have drawn researchers' attention back to melatonin. This review outlines the application of melatonin in SCI, including 1) the relationship between the melatonin rhythm and SCI in clinic; 2) the neuroprotective role of melatonin in experimental traumatic and ischemia/reperfusion SCI, i.e., exhibiting anti-oxidative, anti-inflammatory, and anti-apoptosis effects, facilitating the integrity of the blood-spinal cord barrier, ameliorating edema, preventing neural death, reducing scar formation, and promoting axon regeneration and neuroplasticity; 3) protecting gut microbiota and peripheral organs; 4) synergizing with drugs, rehabilitation training, stem cell therapy, and biomedical material engineering; and 5) the potential side effects. This comprehensive review provides new insights on melatonin as a natural antioxidant therapy in facilitating rehabilitation in SCI.
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Affiliation(s)
- Lei Xie
- Institute of Sports Medicine and Health, Qingdao University, Qingdao, China
- Department of Orthopedic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao, China
| | - Hang Wu
- Department of Orthopedic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao, China
- Department of Orthopedic Surgery, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Xiaohong Huang
- Department of Orthopedic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao, China
- Shandong Institute of Traumatic Orthopedics, Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Tengbo Yu
- Institute of Sports Medicine and Health, Qingdao University, Qingdao, China
- Department of Orthopedic Surgery, Qingdao Hospital, University of Health and Rehabilitation Sciences (Qingdao Municipal Hospital), Qingdao, China
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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: 16] [Impact Index Per Article: 8.0] [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.
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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
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12
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Abstract
The pineal gland is a interface between light-dark cycle and shows neuro-endocrine functions. Melatonin is the primary hormone of pineal gland, secreted at night. The night-time melatonin peak regulates the physiological functions at dark. Melatonin has several unique features as it synchronises internal rhythm with daily and seasonal variations, regulates circadian rhythm and sleep-wake cycle. Physiologically melatonin involves in detoxification of free radicals, immune functions, neuro-protection, oncostatic effects, cardiovascular functions, reproduction, and foetal development. The precise functions of melatonin are exhibited by specific receptors. In relation to pathophysiology, impaired melatonin secretion promotes sleep disorder, cancer progression, type-2 diabetes, and neurodegenerative diseases. Several reports have highlighted the therapeutic benefits of melatonin specially related to cancer protection, sleep disorder, psychiatric disorders, and jet lag problems. This review will touch the most of the area of melatonin-oriented health impacts and its therapeutic aspects.
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13
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Hypotensive effects of melatonin in rats: Focus on the model, measurement, application, and main mechanisms. Hypertens Res 2022; 45:1929-1944. [PMID: 36123396 DOI: 10.1038/s41440-022-01031-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 11/08/2022]
Abstract
The hypotensive effects of melatonin are based on a negative correlation between melatonin levels and blood pressure in humans. However, there is a positive correlation in nocturnal animals that are often used as experimental models in cardiovascular research, and the hypotensive effects and mechanism of melatonin action are often investigated in rats and mice. In rats, the hypotensive effects of melatonin have been studied in normotensive and spontaneously or experimentally induced hypertensive strains. In experimental animals, blood pressure is often measured indirectly during the light (passive) phase of the day by tail-cuff plethysmography, which has limitations regarding data quality and animal well-being compared to telemetry. Melatonin is administered to rats in drinking water, subcutaneously, intraperitoneally, or microinjected into specific brain areas at different times. Experimental data show that the hypotensive effects of melatonin depend on the experimental animal model, blood pressure measurement technique, and the route, time and duration of melatonin administration. The hypotensive effects of melatonin may be mediated through specific membrane G-coupled receptors located in the heart and arteries. Due to melatonin's lipophilic nature, its potential hypotensive effects can interfere with various regulatory mechanisms, such as nitric oxide and reactive oxygen species production and activation of the autonomic nervous and circadian systems. Based on the research conducted on rats, the cardiovascular effects of melatonin are modulatory, delayed, and indirect.
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14
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Moeller JS, Bever SR, Finn SL, Phumsatitpong C, Browne MF, Kriegsfeld LJ. Circadian Regulation of Hormonal Timing and the Pathophysiology of Circadian Dysregulation. Compr Physiol 2022; 12:4185-4214. [PMID: 36073751 DOI: 10.1002/cphy.c220018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Circadian rhythms are endogenously generated, daily patterns of behavior and physiology that are essential for optimal health and disease prevention. Disruptions to circadian timing are associated with a host of maladies, including metabolic disease and obesity, diabetes, heart disease, cancer, and mental health disturbances. The circadian timing system is hierarchically organized, with a master circadian clock located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus and subordinate clocks throughout the CNS and periphery. The SCN receives light information via a direct retinal pathway, synchronizing the master clock to environmental time. At the cellular level, circadian rhythms are ubiquitous, with rhythms generated by interlocking, autoregulatory transcription-translation feedback loops. At the level of the SCN, tight cellular coupling maintains rhythms even in the absence of environmental input. The SCN, in turn, communicates timing information via the autonomic nervous system and hormonal signaling. This signaling couples individual cellular oscillators at the tissue level in extra-SCN brain loci and the periphery and synchronizes subordinate clocks to external time. In the modern world, circadian disruption is widespread due to limited exposure to sunlight during the day, exposure to artificial light at night, and widespread use of light-emitting electronic devices, likely contributing to an increase in the prevalence, and the progression, of a host of disease states. The present overview focuses on the circadian control of endocrine secretions, the significance of rhythms within key endocrine axes for typical, homeostatic functioning, and implications for health and disease when dysregulated. © 2022 American Physiological Society. Compr Physiol 12: 1-30, 2022.
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Affiliation(s)
- Jacob S Moeller
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA
| | - Savannah R Bever
- Department of Psychology, University of California, Berkeley, California, USA
| | - Samantha L Finn
- Department of Psychology, University of California, Berkeley, California, USA
| | | | - Madison F Browne
- Department of Psychology, University of California, Berkeley, California, USA
| | - Lance J Kriegsfeld
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA.,Department of Psychology, University of California, Berkeley, California, USA.,Department of Integrative Biology, University of California, Berkeley, California, USA.,The Helen Wills Neuroscience Institute, University of California, Berkeley, California, USA
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15
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Yuhas PT. Non-24-Hour Sleep–Wake Disorder and Tasimelteon: A Review for Practitioners Who Work with Blind People. JOURNAL OF VISUAL IMPAIRMENT & BLINDNESS 2022. [DOI: 10.1177/0145482x211072521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction This narrative review summarizes the biology of human circadian rhythms; details the epidemiology, clinical manifestation, and diagnosis of non-24-hour sleep–wake disorder (N24SWD); and reviews the efficacy of possible treatments. Methods Searches of targeted phrases, such as “non-24-hour sleep–wake disorder” and “tasimelteon,” were conducted on PubMed between December 2016 and March 2020. Results As the world’s population ages, health practitioners frequently work with people who are blind. Damage to the retinal ganglion cells that signal environmental irradiance levels to the suprachiasmatic nucleus prevents many of these individuals from synchronizing their internal clocks to the 24-hour day. As a result, they experience a condition called N24SWD, where the body’s circadian rhythms fall in and out of phase with the solar cycle. The ability to fall asleep and remain asleep is a complex process that depends on many variables, including the release of the neurohormone melatonin. Melatonin is produced at night and is a key regulator of regular sleep cycles. Periods of interrupted sleep, increased sleep latency, and reduced total sleep time occur when melatonin production peaks during daytime. Thus, many persons with N24SWD have difficulty maintaining normal schedules due in part to the mistimed release of melatonin. Randomized clinical trials have shown that melatonin receptor agonist tasimelteon is an effective therapy for individuals with N24SWD. Other treatments have varying efficacy profiles. Conclusions Although rare, N24SWD is a serious condition that can impair quality of life for blind persons. Tasimelteon appears to be a safe and efficacious treatment option. Implications for practitioners Practitioners can use this information to better understand why blind persons often report difficulties sleeping and to realize that therapeutic options are available to these individuals.
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Affiliation(s)
- Phillip T. Yuhas
- College of Optometry, the Ohio State University, Columbus, OH, USA
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16
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Structural basis of the ligand binding and signaling mechanism of melatonin receptors. Nat Commun 2022; 13:454. [PMID: 35075127 PMCID: PMC8786939 DOI: 10.1038/s41467-022-28111-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/05/2022] [Indexed: 12/13/2022] Open
Abstract
Melatonin receptors (MT1 and MT2 in humans) are family A G protein-coupled receptors that respond to the neurohormone melatonin to regulate circadian rhythm and sleep. Numerous efforts have been made to develop drugs targeting melatonin receptors for the treatment of insomnia, circadian rhythm disorder, and cancer. However, designing subtype-selective melatonergic drugs remains challenging. Here, we report the cryo-EM structures of the MT1-Gi signaling complex with 2-iodomelatonin and ramelteon and the MT2-Gi signaling complex with ramelteon. These structures, together with the reported functional data, reveal that although MT1 and MT2 possess highly similar orthosteric ligand-binding pockets, they also display distinctive features that could be targeted to design subtype-selective drugs. The unique structural motifs in MT1 and MT2 mediate structural rearrangements with a particularly wide opening on the cytoplasmic side. Gi is engaged in the receptor core shared by MT1 and MT2 and presents a conformation deviating from those in other Gi complexes. Together, our results provide new clues for designing melatonergic drugs and further insights into understanding the G protein coupling mechanism.
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17
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Klosen P. Nonradioactive In Situ Hybridization of MT1 Melatonin Receptor for the Identification of Melatonin Target Cells. Methods Mol Biol 2022; 2550:219-241. [PMID: 36180696 DOI: 10.1007/978-1-0716-2593-4_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Identifying and phenotyping the target cells of a neuroendocrine messenger is one of the key steps to understand neuroendocrine networks and the physiological action of such messengers. In the absence of reliable antibodies directed against the receptor of a neuroendocrine messenger, detecting the expression of the messenger RNA of this receptor is an important tool to identify the target cells of a neuroendocrine messenger such as melatonin. While radioactive in situ hybridization has a higher sensitivity, nonradioactive in situ hybridization has a much better cellular resolution than radioactive in situ hybridization and is therefore better suited for phenotyping the target cells of melatonin. Here we describe a nonradioactive in situ hybridization protocol with its adaptations to various types of histological preparations. This protocol allowed the phenotyping of melatonin target cells in the pars tuberalis of the adenohypophysis, leading to the discovery of photoperiodic melatonin signaling from the pars tuberalis to the hypothalamus.
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Affiliation(s)
- Paul Klosen
- Institute of Cellular and Integrative Neurosciences, INCI CNRS UPR3212, University of Strasbourg, Strasbourg, France.
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18
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Nikolaev G, Robeva R, Konakchieva R. Membrane Melatonin Receptors Activated Cell Signaling in Physiology and Disease. Int J Mol Sci 2021; 23:ijms23010471. [PMID: 35008896 PMCID: PMC8745360 DOI: 10.3390/ijms23010471] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 02/07/2023] Open
Abstract
The pineal hormone melatonin has attracted great scientific interest since its discovery in 1958. Despite the enormous number of basic and clinical studies the exact role of melatonin in respect to human physiology remains elusive. In humans, two high-affinity receptors for melatonin, MT1 and MT2, belonging to the family of G protein-coupled receptors (GPCRs) have been cloned and identified. The two receptor types activate Gi proteins and MT2 couples additionally to Gq proteins to modulate intracellular events. The individual effects of MT1 and MT2 receptor activation in a variety of cells are complemented by their ability to form homo- and heterodimers, the functional relevance of which is yet to be confirmed. Recently, several melatonin receptor genetic polymorphisms were discovered and implicated in pathology-for instance in type 2 diabetes, autoimmune disease, and cancer. The circadian patterns of melatonin secretion, its pleiotropic effects depending on cell type and condition, and the already demonstrated cross-talks of melatonin receptors with other signal transduction pathways further contribute to the perplexity of research on the role of the pineal hormone in humans. In this review we try to summarize the current knowledge on the membrane melatonin receptor activated cell signaling in physiology and pathology and their relevance to certain disease conditions including cancer.
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Affiliation(s)
- Georgi Nikolaev
- Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1504 Sofia, Bulgaria;
- Correspondence:
| | - Ralitsa Robeva
- Department of Endocrinology, Faculty of Medicine, Medical University, 1431 Sofia, Bulgaria;
| | - Rossitza Konakchieva
- Faculty of Biology, Sofia University “St. Kliment Ohridski”, 1504 Sofia, Bulgaria;
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19
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Tse LH, Wong YH. Modeling the Heterodimer Interfaces of Melatonin Receptors. Front Cell Neurosci 2021; 15:725296. [PMID: 34690701 PMCID: PMC8529217 DOI: 10.3389/fncel.2021.725296] [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: 06/15/2021] [Accepted: 08/16/2021] [Indexed: 11/16/2022] Open
Abstract
Melatonin receptors are Class A G protein-coupled receptors (GPCRs) that regulate a plethora of physiological activities in response to the rhythmic secretion of melatonin from the pineal gland. Melatonin is a key regulator in the control of circadian rhythm and has multiple functional roles in retinal physiology, memory, immunomodulation and tumorigenesis. The two subtypes of human melatonin receptors, termed MT1 and MT2, utilize overlapping signaling pathways although biased signaling properties have been reported in some cellular systems. With the emerging concept of GPCR dimerization, melatonin receptor heterodimers have been proposed to participate in system-biased signaling. Here, we used computational approaches to map the dimerization interfaces of known heterodimers of melatonin receptors, including MT1/MT2, MT1/GPR50, MT2/GPR50, and MT2/5-HT2C. By homology modeling and membrane protein docking analyses, we have identified putative preferred interface interactions within the different pairs of melatonin receptor dimers and provided plausible structural explanations for some of the unique pharmacological features of specific heterodimers previously reported. A thorough understanding of the molecular basis of melatonin receptor heterodimers may enable the development of new therapeutic approaches against aliments involving these heterodimeric receptors.
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Affiliation(s)
- Lap Hang Tse
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, SAR China
| | - Yung Hou Wong
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, SAR China.,State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, SAR China.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, SAR China
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20
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Empowering Melatonin Therapeutics with Drosophila Models. Diseases 2021; 9:diseases9040067. [PMID: 34698120 PMCID: PMC8544433 DOI: 10.3390/diseases9040067] [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: 08/01/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 12/15/2022] Open
Abstract
Melatonin functions as a central regulator of cell and organismal function as well as a neurohormone involved in several processes, e.g., the regulation of the circadian rhythm, sleep, aging, oxidative response, and more. As such, it holds immense pharmacological potential. Receptor-mediated melatonin function mainly occurs through MT1 and MT2, conserved amongst mammals. Other melatonin-binding proteins exist. Non-receptor-mediated activities involve regulating the mitochondrial function and antioxidant cascade, which are frequently affected by normal aging as well as disease. Several pathologies display diseased or dysfunctional mitochondria, suggesting melatonin may be used therapeutically. Drosophila models have extensively been employed to study disease pathogenesis and discover new drugs. Here, we review the multiple functions of melatonin through the lens of functional conservation and model organism research to empower potential melatonin therapeutics to treat neurodegenerative and renal diseases.
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21
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Iqubal A, Iqubal MK, Fazal SA, Pottoo FH, Haque SE. Nutraceuticals and their Derived Nano-formulations for the Prevention and Treatment of Alzheimer's disease. Curr Mol Pharmacol 2021; 15:23-50. [PMID: 33687906 DOI: 10.2174/1874467214666210309115605] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/22/2020] [Accepted: 12/02/2020] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease is one of the common chronic neurological disorders and associated with cognitive dysfunction, depression and progressive dementia. Presence of β-amyloid or senile plaques, hyper-phosphorylated tau proteins, neurofibrillary tangle, oxidative-nitrative stress, mitochondrial dysfunction, endoplasmic reticulum stress, neuroinflammation and derailed neurotransmitter status are the hallmark of AD. Currently, donepezil, memantine, rivastigmine and galantamine are approved by the FDA for symptomatic management. It is well-known that these approved drugs only exert symptomatic relief and possess poor patient-compliance. Additionally, various published evidence shows the neuroprotective potential of various nutraceuticals via their antioxidant, anti-inflammatory and anti-apoptotic effects in the preclinical and clinical studies. These nutraceuticals possess a significant neuroprotective potential and hence, can be a future pharmacotherapeutic for the management and treatment of AD. However, nutraceutical suffers from certain major limitations such as poor solubility, low bioavailability, low stability, fast hepatic-metabolism and larger particle size. These pharmacokinetic attributes restrict their entry into the brain via the blood-brain barrier. Therefore, to over such issues, various nanoformulation of nutraceuticals was developed, that allows their effective delivery into brain owning to reduced particle size, increased lipophilicity increased bioavailability and avoidance of fast hepatic metabolism. Thus, in this review, we have discussed the etiology of AD, focused on the pharmacotherapeutics of nutraceuticals with preclinical and clinical evidence, discussed pharmaceutical limitation and regulatory aspects of nutraceuticals to ensure safety and efficacy. We further explored the latitude of various nanoformulation of nutraceuticals as a novel approach to overcome the existing pharmaceutical limitation and for effective delivery into the brain.
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Affiliation(s)
- Ashif Iqubal
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi-110062. India
| | - Mohammad Kashif Iqubal
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi-110062. India
| | - Syed Abul Fazal
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi-110062. India
| | - Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal, University, P.O.BOX 1982, Damman, 31441. Saudi Arabia
| | - Syed Ehtaishamul Haque
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi-110062. India
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22
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Xie WQ, Chen SF, Tao XH, Zhang LY, Hu PW, Pan WL, Fan YB, Li YS. Melatonin: Effects on Cartilage Homeostasis and Therapeutic Prospects in Cartilage-related Diseases. Aging Dis 2021; 12:297-307. [PMID: 33532142 PMCID: PMC7801270 DOI: 10.14336/ad.2020.0519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/19/2020] [Indexed: 12/25/2022] Open
Abstract
Cartilage is a relatively simple connective tissue that plays a variety of roles in the human body, including joint support and protection, load bearing of the intervertebral discs, joint lubrication, formation of the external structure of the ears and nose and support of the trachea. The maintenance of cartilage homeostasis is therefore crucial. Cartilage-related diseases are difficult to diagnose and treat because their molecular and pathological mechanisms are not fully understood. Melatonin, which has a wide range of physiological effects, is an endocrine hormone mainly secreted by the pineal gland. Its biological effects include its antioxidant, antiaging, analgesic, and hypnotic effects and its ability to stabilize the circadian rhythm. In recent years, research on cartilage homeostasis and melatonin has been increasing, and melatonin has gradually been used in the treatment of cartilage-related diseases. Therefore, this article will briefly review the role of melatonin in cartilage homeostasis, including its anti-inflammatory effects and effects in protecting cartilage from damage by other factors and promoting chondrocyte growth and the expression of cartilage-related genes. Based on the above, the current status and future developmental direction of melatonin in the treatment of cartilage-related diseases are also discussed, demonstrating the broad prospects of melatonin in maintaining cartilage homeostasis and treating cartilage injury-related diseases.
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Affiliation(s)
- Wen-Qing Xie
- 1Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.,6National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Song-Feng Chen
- 2Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, Henan, China
| | - Xiao-Hua Tao
- 3Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
| | - Li-Yang Zhang
- 4Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Pei-Wu Hu
- 5Department of Scientific Research, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Wei-Li Pan
- 3Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
| | - Yi-Bin Fan
- 3Department of Dermatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310000, China
| | - Yu-Sheng Li
- 1Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.,6National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
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23
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Oishi A, Gbahou F, Jockers R. Melatonin receptors, brain functions, and therapies. HANDBOOK OF CLINICAL NEUROLOGY 2021; 179:345-356. [PMID: 34225974 DOI: 10.1016/b978-0-12-819975-6.00022-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In mammals, including humans, the neurohormone melatonin is mainly secreted from the pineal gland at night and acts on two high-affinity G protein-coupled receptors, the melatonin MT1 and MT2 receptors. Major functions of melatonin receptors in the brain are the regulation of circadian rhythms and sleep. Correspondingly, the main indications of the currently available drugs for these receptors indicate this as targets. Yet these drugs may not only improve circadian rhythm- and sleep-related disorders but may also be beneficial for complex diseases like major depression, Alzheimer's disease, autism, and attention-deficit/hyperactivity disorders. Here, we will focus on the hypothalamic functions of melatonin receptors by updating our knowledge on their hypothalamic expression pattern at normal, aged, and disease states, by discussing their capacity to regulate circadian rhythms and sleep and by presenting the clinical applications of the melatonin receptor-targeting drugs ramelteon, tasimelteon, and agomelatine or of prolonged-release melatonin formulations. Finally, we speculate about future trends in the field of melatonin receptor drugs.
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Affiliation(s)
- Atsuro Oishi
- Institut Cochin, Université de Paris, Paris, France
| | | | - Ralf Jockers
- Institut Cochin, Université de Paris, Paris, France.
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24
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Pevet P, Challet E, Felder-Schmittbuhl MP. Melatonin and the circadian system: Keys for health with a focus on sleep. HANDBOOK OF CLINICAL NEUROLOGY 2021; 179:331-343. [PMID: 34225973 DOI: 10.1016/b978-0-12-819975-6.00021-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Melatonin (MLT), secreted during the night by the pineal gland, is an efferent hormonal signal of the master circadian clock located in the suprachiasmatic nucleus (SCN). Consequently, it is a reliable phase marker of the SCN clock. If one defines as "chronobiotic," a drug able to influence the phase and/or the period of the circadian clock, MLT is a very potent one. The most convincing data obtained so far come from studies on totally blind individuals. Exogenous MLT administered daily entrains the sleep-wake cycle of these individuals to a 24-h cycle. MLT, however, is not essential to sleep. In nocturnally, active mammals, MLT is released during the night concomitantly with the daily period of wakefulness. Therefore, MLT cannot be simply considered as a sleep hormone, but rather as a signal of darkness. Its role in the circadian system is to reinforce nighttime physiology, including timing of the sleep-wake cycle and other circadian rhythms. MLT exerts its effects on the sleep cycle especially by a direct action on the master circadian clock. The sleep-wake cycle is depending not only on the circadian clock but also on an orchestrated network of different centers in the brain. Thus, the control of sleep-wake rhythm might be explained by a parallel and concomitant action of MLT on the master clock (chronobiotic effect) and on sleep-related structures within the brain. MLT acts through two high-affinity membrane receptors (MT1 and MT2) with striking differences in their distribution pattern. MLT is a powerful synchronizer of human circadian rhythms, thus justifying the use of MLT and MLT agonists in clinical medicine as pharmacological tools to manipulate the sleep-wake cycle, and to treat sleep disorders and other circadian disorders. Available MLT analogs/drugs are all nonspecific MT1/MT2 agonists. The development of new ligands which are highly selectivity for each subtype is clearly a new challenge for the field and will be at the root of new therapeutic agents for curing specific pathologies, including sleep disorders.
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Affiliation(s)
- Paul Pevet
- Institute of Cellular and Integrative Neurosciences, CNRS, University of Strasbourg, Strasbourg, France.
| | - Etienne Challet
- Institute of Cellular and Integrative Neurosciences, CNRS, University of Strasbourg, Strasbourg, France
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25
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Gubin D, Weinert D, Solovieva SV, Durov AM, Litvinova NS, Danilova LA, Prokopiev NY, Trushnikov DY, Kartashova EA. Melatonin attenuates light-at-night effects on systolic blood pressure and body temperature but does not affect diastolic blood pressure and heart rate circadian rhythms. BIOL RHYTHM RES 2020; 51:780-793. [DOI: 10.1080/09291016.2018.1564586] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 12/18/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Denis Gubin
- Department of Biology, Tyumen Medical University, Tyumen, Russia
- Tyumen Cardiology Research Center, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia
| | - D. Weinert
- Institute of Biology/Zoology, Martin Luther University, Halle-Wittenberg, Germany
| | - S. V. Solovieva
- Department of Biology, Tyumen Medical University, Tyumen, Russia
| | - A. M. Durov
- Department of Biology, Tyumen Medical University, Tyumen, Russia
- Department of Sport Medicine, Tyumen State University, Tyumen, Russia
| | - N. S. Litvinova
- Department of Biology, Tyumen Medical University, Tyumen, Russia
| | - L. A. Danilova
- Department of Biology, Tyumen Medical University, Tyumen, Russia
| | - N. Y. Prokopiev
- Institute of Biology/Zoology, Martin Luther University, Halle-Wittenberg, Germany
| | - D. Y. Trushnikov
- Department of Biology, Tyumen Medical University, Tyumen, Russia
| | - E. A. Kartashova
- Department of Biology, Tyumen Medical University, Tyumen, Russia
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26
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Tchekalarova J, Kortenska L, Ivanova N, Atanasova M, Marinov P. Agomelatine treatment corrects impaired sleep-wake cycle and sleep architecture and increases MT 1 receptor as well as BDNF expression in the hippocampus during the subjective light phase of rats exposed to chronic constant light. Psychopharmacology (Berl) 2020; 237:503-518. [PMID: 31720718 DOI: 10.1007/s00213-019-05385-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/25/2019] [Indexed: 10/25/2022]
Abstract
RATIONALE Exposure to chronic constant light (CCL) has a detrimental impact on circadian rhythms of motor activity and sleep/wake cycles. Agomelatine is an atypical antidepressant showing a chronotropic activity. OBJECTIVES In this study, we explored the role of melatonin (MT) receptors and brain-derived neurotrophic factor (BDNF) in the brain in the mechanism underlying the effects of agomelatine on diurnal variations of motor activity, sleep/wake cycle, and sleep architecture in a rat model of CCL. METHODS In Experiment #1, home cage activity was monitored automatically with cameras for a period of 24 h. The diurnal rhythm of MT1, MT2 receptors, and BDNF expression in the hippocampus and frontal cortex (FC), was tested using the ELISA test. In Experiment #2, rats were equipped with electroencephalographic (EEG) and electromyographic (EMG) electrodes and recordings were made under basal conditions (12:12 LD cycle + vehicle), LL + vehicle and LL + agomelatine (40 mg/kg/day for 21 days). RESULTS The rats exposed to CCL showed an impaired diurnal rhythm of motor activity and sleep/wake cycle with reduced NREM sleep and delta power and increased REM sleep and theta power. The duration and number of episodes of the wake were diminished during the subjective dark phase in this group. The circadian rhythm of MT1 and MT2 receptors and their expression did not change in the hippocampus and FC under CCL exposure, while the BDNF levels in the hippocampus decreased during the subjective light phase. Agomelatine restored the diurnal rhythm of motor activity, disturbed sleep/wake cycle, and sleep architecture, which effect was accompanied by an increase in MT1 receptor and BDNF expression in the hippocampus at 10:00 in CCL rats. CONCLUSIONS These findings support the value of agomelatine as an antidepressant that can adjust circadian homeostasis of motor activity and sleep/wake cycle in a CCL model.
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Affiliation(s)
- Jana Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), 1113, Sofia, Bulgaria.
| | - Lidia Kortenska
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), 1113, Sofia, Bulgaria
| | - Natasha Ivanova
- Institute of Neurobiology, Bulgarian Academy of Sciences (BAS), 1113, Sofia, Bulgaria
| | - Milena Atanasova
- Department of Biology, Medical University of Pleven, 5800, Pleven, Bulgaria
| | - Pencho Marinov
- Institute of Information and Communication Technologies, BAS, 1113, Sofia, Bulgaria
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Beker MC, Caglayan B, Caglayan AB, Kelestemur T, Yalcin E, Caglayan A, Kilic U, Baykal AT, Reiter RJ, Kilic E. Interaction of melatonin and Bmal1 in the regulation of PI3K/AKT pathway components and cellular survival. Sci Rep 2019; 9:19082. [PMID: 31836786 PMCID: PMC6910929 DOI: 10.1038/s41598-019-55663-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 11/22/2019] [Indexed: 01/08/2023] Open
Abstract
The circadian rhythm is driven by a master clock within the suprachiasmatic nucleus which regulates the rhythmic secretion of melatonin. Bmal1 coordinates the rhythmic expression of transcriptome and regulates biological activities, involved in cell metabolism and aging. However, the role of Bmal1 in cellular- survival, signaling, its interaction with intracellular proteins, and how melatonin regulates its expression is largely unclear. Here we observed that melatonin increases the expression of Bmal1 and both melatonin and Bmal1 increase cellular survival after oxygen glucose deprivation (OGD) while the inhibition of Bmal1 resulted in the decreased cellular survival without affecting neuroprotective effects of melatonin. By using a planar surface immunoassay for PI3K/AKT signaling pathway components, we revealed that both melatonin and Bmal1 increased phosphorylation of AKT, ERK-1/2, PDK1, mTOR, PTEN, GSK-3αβ, and p70S6K. In contrast, inhibition of Bmal1 resulted in decreased phosphorylation of these proteins, which the effect of melatonin on these signaling molecules was not affected by the absence of Bmal1. Besides, the inhibition of PI3K/AKT decreased Bmal1 expression and the effect of melatonin on Bmal1 after both OGD in vitro and focal cerebral ischemia in vivo. Our data demonstrate that melatonin controls the expression of Bmal1 via PI3K/AKT signaling, and Bmal1 plays critical roles in cellular survival via activation of survival kinases.
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Affiliation(s)
- Mustafa C Beker
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Berrak Caglayan
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Medical Biology, International School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Ahmet B Caglayan
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Taha Kelestemur
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Esra Yalcin
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Aysun Caglayan
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Ulkan Kilic
- Department of Medical Biology, School of Medicine, University of Health Sciences, 34668, Istanbul, Turkey
| | - Ahmet T Baykal
- Department of Medical Biochemistry, School of Medicine, Acibadem Mehmet Ali Aydinlar University, 34752, Istanbul, Turkey
| | - Russel J Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, 78229, Texas, USA
| | - Ertugrul Kilic
- Regenerative and Restorative Medicine Research Center, Istanbul Medipol University, 34810, Istanbul, Turkey.
- Department of Physiology, School of Medicine, Istanbul Medipol University, 34810, Istanbul, Turkey.
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Jin Y, Choi J, Lee S, Kim JW, Hong Y. Pathogenetical and Neurophysiological Features of Patients with Autism Spectrum Disorder: Phenomena and Diagnoses. J Clin Med 2019; 8:E1588. [PMID: 31581672 PMCID: PMC6832208 DOI: 10.3390/jcm8101588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/29/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is accompanied by social deficits, repetitive and restricted interests, and altered brain development. The majority of ASD patients suffer not only from ASD itself but also from its neuropsychiatric comorbidities. Alterations in brain structure, synaptic development, and misregulation of neuroinflammation are considered risk factors for ASD and neuropsychiatric comorbidities. Electroencephalography has been developed to quantitatively explore effects of these neuronal changes of the brain in ASD. The pineal neurohormone melatonin is able to contribute to neural development. Also, this hormone has an inflammation-regulatory role and acts as a circadian key regulator to normalize sleep. These functions of melatonin may play crucial roles in the alleviation of ASD and its neuropsychiatric comorbidities. In this context, this article focuses on the presumable role of melatonin and suggests that this hormone could be a therapeutic agent for ASD and its related neuropsychiatric disorders.
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Affiliation(s)
- Yunho Jin
- Department of Rehabilitation Science, Graduate School of Inje University, Gimhae 50834, Korea.
- Ubiquitous Healthcare & Anti-aging Research Center (u-HARC), Inje University, Gimhae 50834, Korea.
- Biohealth Products Research Center (BPRC), Inje University, Gimhae 50834, Korea.
- Department of Physical Therapy, College of Healthcare Medical Science & Engineering, Inje University, Gimhae 50834, Korea.
| | - Jeonghyun Choi
- Department of Rehabilitation Science, Graduate School of Inje University, Gimhae 50834, Korea.
- Ubiquitous Healthcare & Anti-aging Research Center (u-HARC), Inje University, Gimhae 50834, Korea.
- Biohealth Products Research Center (BPRC), Inje University, Gimhae 50834, Korea.
- Department of Physical Therapy, College of Healthcare Medical Science & Engineering, Inje University, Gimhae 50834, Korea.
| | - Seunghoon Lee
- Gimhae Industry Promotion & Biomedical Foundation, Gimhae 50969, Korea.
| | - Jong Won Kim
- Department of Healthcare Information Technology, College of Bio-Nano Information Technology, Inje University, Gimhae 50834, Korea.
| | - Yonggeun Hong
- Department of Rehabilitation Science, Graduate School of Inje University, Gimhae 50834, Korea.
- Ubiquitous Healthcare & Anti-aging Research Center (u-HARC), Inje University, Gimhae 50834, Korea.
- Biohealth Products Research Center (BPRC), Inje University, Gimhae 50834, Korea.
- Department of Physical Therapy, College of Healthcare Medical Science & Engineering, Inje University, Gimhae 50834, Korea.
- Department of Medicine, Division of Hematology/Oncology, Harvard Medical School-Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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29
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Klosen P, Lapmanee S, Schuster C, Guardiola B, Hicks D, Pevet P, Felder-Schmittbuhl MP. MT1 and MT2 melatonin receptors are expressed in nonoverlapping neuronal populations. J Pineal Res 2019; 67:e12575. [PMID: 30937953 DOI: 10.1111/jpi.12575] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/07/2019] [Accepted: 03/25/2019] [Indexed: 12/15/2022]
Abstract
Melatonin (MLT) exerts its physiological effects principally through two high-affinity membrane receptors MT1 and MT2. Understanding the exact mechanism of MLT action necessitates the use of highly selective agonists/antagonists to stimulate/inhibit a given MLT receptor. The respective distribution of MT1 and MT2 within the CNS and elsewhere is controversial, and here we used a "knock-in" strategy replacing MT1 or MT2 coding sequences with a LacZ reporter. The data show striking differences in the distribution of MT1 and MT2 receptors in the mouse brain: whereas the MT1 subtype was expressed in very few structures (notably including the suprachiasmatic nucleus and pars tuberalis), MT2 subtype receptors were identified within numerous brain regions including the olfactory bulb, forebrain, hippocampus, amygdala and superior colliculus. Co-expression of the two subtypes was observed in very few structures, and even within these areas they were rarely present in the same individual cell. In conclusion, the expression and distribution of MT2 receptors are much more widespread than previously thought, and there is virtually no correspondence between MT1 and MT2 cellular expression. The precise phenotyping of cells/neurons containing MT1 or MT2 receptor subtypes opens new perspectives for the characterization of links between MLT brain targets, MLT actions and specific MLT receptor subtypes.
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Affiliation(s)
- Paul Klosen
- Institute for Cellular and Integrative Neurosciences (UPR 3212), CNRS and University of Strasbourg, Strasbourg, France
| | - Sarawut Lapmanee
- Institute for Cellular and Integrative Neurosciences (UPR 3212), CNRS and University of Strasbourg, Strasbourg, France
| | | | | | - David Hicks
- Institute for Cellular and Integrative Neurosciences (UPR 3212), CNRS and University of Strasbourg, Strasbourg, France
| | - Paul Pevet
- Institute for Cellular and Integrative Neurosciences (UPR 3212), CNRS and University of Strasbourg, Strasbourg, France
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Song J. Pineal gland dysfunction in Alzheimer's disease: relationship with the immune-pineal axis, sleep disturbance, and neurogenesis. Mol Neurodegener 2019; 14:28. [PMID: 31296240 PMCID: PMC6624939 DOI: 10.1186/s13024-019-0330-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/01/2019] [Indexed: 12/15/2022] Open
Abstract
Alzheimer’s disease (AD) is a globally common neurodegenerative disease, which is accompanied by alterations to various lifestyle patterns, such as sleep disturbance. The pineal gland is the primary endocrine organ that secretes hormones, such as melatonin, and controls the circadian rhythms. The decrease in pineal gland volume and pineal calcification leads to the reduction of melatonin production. Melatonin has been reported to have multiple roles in the central nervous system (CNS), including improving neurogenesis and synaptic plasticity, suppressing neuroinflammation, enhancing memory function, and protecting against oxidative stress. Recently, reduced pineal gland volume and pineal calcification, accompanied by cognitive decline and sleep disturbances have been observed in AD patients. Here, I review current significant evidence of the contribution of pineal dysfunction in AD to the progress of AD neuropathology. I suggest new insights to understanding the relationship between AD pathogenesis and pineal gland function.
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Affiliation(s)
- Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun, 58128, Jeollanam-do, Republic of Korea.
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31
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Melatonin MT1 receptor as a novel target in neuropsychopharmacology: MT1 ligands, pathophysiological and therapeutic implications, and perspectives. Pharmacol Res 2019; 144:343-356. [DOI: 10.1016/j.phrs.2019.04.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/06/2019] [Accepted: 04/11/2019] [Indexed: 12/15/2022]
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32
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Melatonin MT 1 and MT 2 Receptors Exhibit Distinct Effects in the Modulation of Body Temperature across the Light/Dark Cycle. Int J Mol Sci 2019; 20:ijms20102452. [PMID: 31108968 PMCID: PMC6566544 DOI: 10.3390/ijms20102452] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/06/2019] [Accepted: 05/10/2019] [Indexed: 12/14/2022] Open
Abstract
Melatonin (MLT) is a neurohormone that regulates many physiological functions including sleep, pain, thermoregulation, and circadian rhythms. MLT acts mainly through two G-protein-coupled receptors named MT1 and MT2, but also through an MLT type-3 receptor (MT3). However, the role of MLT receptor subtypes in thermoregulation is still unknown. We have thus investigated the effects of selective and non-selective MLT receptor agonists/antagonists on body temperature (Tb) in rats across the 12/12-h light-dark cycle. Rectal temperature was measured every 15 min from 4:00 a.m. to 9:30 a.m. and from 4:00 p.m. to 9:30 p.m., following subcutaneous injection of each compound at either 5:00 a.m. or 5:00 p.m. MLT (40 mg/kg) had no effect when injected at 5 a.m., whereas it decreased Tb during the light phase only when injected at 5:00 p.m. This effect was blocked by the selective MT2 receptor antagonist 4P-PDOT and the non-selective MT1/MT2 receptor antagonist, luzindole, but not by the α1/MT3 receptors antagonist prazosin. However, unlike MLT, neither the selective MT1 receptor partial agonist UCM871 (14 mg/kg) nor the selective MT2 partial agonist UCM924 (40 mg/kg) altered Tb during the light phase. In contrast, UCM871 injected at 5:00 p.m. increased Tb at the beginning of the dark phase, whereas UCM924 injected at 5:00 a.m. decreased Tb at the end of the dark phase. These effects were blocked by luzindole and 4P-PDOT, respectively. The MT3 receptor agonist GR135531 (10 mg/kg) did not affect Tb. These data suggest that the simultaneous activation of both MT1 and MT2 receptors is necessary to regulate Tb during the light phase, whereas in a complex but yet unknown manner, they regulate Tb differently during the dark phase. Overall, MT1 and MT2 receptors display complementary but also distinct roles in modulating circadian fluctuations of Tb.
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33
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Gobbi G, Comai S. Differential Function of Melatonin MT 1 and MT 2 Receptors in REM and NREM Sleep. Front Endocrinol (Lausanne) 2019; 10:87. [PMID: 30881340 PMCID: PMC6407453 DOI: 10.3389/fendo.2019.00087] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/31/2019] [Indexed: 11/13/2022] Open
Abstract
The pathophysiological function of the G-protein coupled melatonin MT1 and MT2 receptors has not yet been well-clarified. Recent advancements using selective MT1/ MT2 receptor ligands and MT1/MT2 receptor knockout mice have suggested that the activation of the MT1 receptors are mainly implicated in the regulation of rapid eye movement (REM) sleep, whereas the MT2 receptors selectively increase non-REM (NREM) sleep. Studies in mutant mice show that MT1 knockout mice have an increase in NREM sleep and a decrease in REM sleep, while MT2 knockout mice a decrease in NREM sleep. The localization of MT1 receptors is also distinct from MT2 receptors; for example, MT2 receptors are located in the reticular thalamus (NREM area), while the MT1 receptors in the Locus Coeruleus and lateral hypothalamus (REM areas). Altogether, these findings suggest that these two receptors not only have a very specialized function in sleep, but that they may also modulate opposing effects. These data also suggest that mixed MT1-MT2 receptors ligands are not clinically recommended given their opposite roles in physiological functions, confirmed by the modest effects of melatonin or MT1/MT2 non-selective agonists when used in both preclinical and clinical studies as hypnotic drugs. In sum, MT1 and MT2 receptors have specific roles in the modulation of sleep, and consequently, selective ligands with agonist, antagonist, or partial agonist properties could have therapeutic potential for sleep; while the MT2 agonists or partial agonists might be indicated for NREM-related sleep and/or anxiety disorders, the MT1 agonists or partial agonists might be so for REM-related sleep disorders. Furthermore, MT1 but not MT2 receptors seem involved in the regulation of the circadian rhythm. Future research will help further develop MT1 and/or MT2 receptors as targets for neuropsychopharmacology drug development.
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Affiliation(s)
- Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Stefano Comai
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, QC, Canada
- San Raffaele Scientific Institute and Vita Salute University, Milan, Italy
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Elevated Serum Melatonin under Constant Darkness Enhances Neural Repair in Spinal Cord Injury through Regulation of Circadian Clock Proteins Expression. J Clin Med 2019; 8:jcm8020135. [PMID: 30678072 PMCID: PMC6406284 DOI: 10.3390/jcm8020135] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/18/2019] [Accepted: 01/20/2019] [Indexed: 11/17/2022] Open
Abstract
We investigated the effects of environmental lighting conditions regulating endogenous melatonin production on neural repair, following experimental spinal cord injury (SCI). Rats were divided into three groups randomly: the SCI + L/D (12/12-h light/dark), SCI + LL (24-h constant light), and SCI + DD (24-h constant dark) groups. Controlled light/dark cycle was pre-applied 2 weeks before induction of spinal cord injury. There was a significant increase in motor recovery as well as body weight from postoperative day (POD) 7 under constant darkness. However, spontaneous elevation of endogenous melatonin in cerebrospinal fluid was seen at POD 3 in all of the SCI rats, which was enhanced in SCI + DD group. Augmented melatonin concentration under constant dark condition resulted in facilitation of neuronal differentiation as well as inhibition of primary cell death. In the rostrocaudal region, elevated endogenous melatonin concentration promoted neural remodeling in acute phase including oligodendrogenesis, excitatory synaptic formation, and axonal outgrowth. The changes were mediated via NAS-TrkB-AKT/ERK signal transduction co-regulated by the circadian clock mechanism, leading to rapid motor recovery. In contrast, exposure to constant light exacerbated the inflammatory responses and neuroglial loss. These results suggest that light/dark control in the acute phase might be a considerable environmental factor for a favorable prognosis after SCI.
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35
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Abhimanyu, Coussens AK. The role of UV radiation and vitamin D in the seasonality and outcomes of infectious disease. Photochem Photobiol Sci 2018; 16:314-338. [PMID: 28078341 DOI: 10.1039/c6pp00355a] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The seasonality of infectious disease outbreaks suggests that environmental conditions have a significant effect on disease risk. One of the major environmental factors that can affect this is solar radiation, primarily acting through ultraviolet radiation (UVR), and its subsequent control of vitamin D production. Here we show how UVR and vitamin D, which are modified by latitude and season, can affect host and pathogen fitness and relate them to the outcomes of bacterial, viral and vector-borne infections. We conducted a thorough comparison of the molecular and cellular mechanisms of action of UVR and vitamin D on pathogen fitness and host immunity and related these to the effects observed in animal models and clinical trials to understand their independent and complementary effects on infectious disease outcome. UVR and vitamin D share common pathways of innate immune activation primarily via antimicrobial peptide production, and adaptive immune suppression. Whilst UVR can induce vitamin D-independent effects in the skin, such as the generation of photoproducts activating interferon signaling, vitamin D has a larger systemic effect due to its autocrine and paracrine modulation of cellular responses in a range of tissues. However, the seasonal patterns in infectious disease prevalence are not solely driven by variation in UVR and vitamin D levels across latitudes. Vector-borne pathogens show a strong seasonality of infection correlated to climatic conditions favoring their replication. Conversely, pathogens, such as influenza A virus, Mycobacterium tuberculosis and human immunodeficiency virus type 1, have strong evidence to support their interaction with vitamin D. Thus, UVR has both vitamin D-dependent and independent effects on infectious diseases; these effects vary depending on the pathogen of interest and the effects can be complementary or antagonistic.
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Affiliation(s)
- Abhimanyu
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa.
| | - Anna K Coussens
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa. and Division of Medical Microbiology, Department of Pathology, University of Cape Town, Anzio Rd, Observatory, 7925, Western Cape, South Africa
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36
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Tchekalarova J, Stoynova T, Ilieva K, Mitreva R, Atanasova M. Agomelatine treatment corrects symptoms of depression and anxiety by restoring the disrupted melatonin circadian rhythms of rats exposed to chronic constant light. Pharmacol Biochem Behav 2018; 171:1-9. [PMID: 29807067 DOI: 10.1016/j.pbb.2018.05.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 12/25/2022]
Abstract
Desynchronization of circadian rhythms is a hallmark of depression. The antidepressant agomelatine, which is an MT1/MT2 melatonin receptor agonist/5-HT2C serotonin receptor antagonist has advantages compared to the selective serotonin reuptake inhibitors as a circadian phase-shifting agent. The present study was designed to explore whether agomelatine is able to have an antidepressant effect on rats exposed to chronic constant light (CCL) for 6 weeks. Focus is also placed on whether this activity affects diurnal rhythms of depressive-like symptoms and is associated with restoration of impaired circadian rhythms in plasma melatonin and corticosterone. We report that CCL induced a depressive-like symptoms associated with decreased grooming in the splash test during the subjective light/inactive phase. Anhedonia-like deficit in the saccharine preference test and increased immobility in the forced swimming test were both detected during the subjective dark/active phase. The disturbed emotional fluctuations due to CCL were corrected by agomelatine treatment (40 mg/kg, i.p. for 3 weeks). Agomelatine also restored novelty-induced hypophagia, which reflects an anxiety state, during the subjective Light and Dark phase, respectively, in rats exposed to CCL. Parallel to the observed positive influence on behavior, this melatonin analogue restored impaired circadian patterns of plasma melatonin but not that of corticosterone. These findings demonstrated the antidepressant-like effect of agomelatine in rats exposed to CCL possibly exerted via correction of melatonin rhythms and are suggestive of the therapeutic potential of this drug in a subpopulation of people characterized by a melatonin deficit.
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Affiliation(s)
- Jana Tchekalarova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
| | - Tzveta Stoynova
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Kalina Ilieva
- Department of Biology, Medical University of Pleven, Pleven 5800, Bulgaria
| | - Rumyana Mitreva
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
| | - Milena Atanasova
- Department of Biology, Medical University of Pleven, Pleven 5800, Bulgaria
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Sadhukhan P, Saha S, Dutta S, Mahalanobish S, Sil PC. Nutraceuticals: An emerging therapeutic approach against the pathogenesis of Alzheimer's disease. Pharmacol Res 2018; 129:100-114. [PMID: 29183770 DOI: 10.1016/j.phrs.2017.11.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD) is regarded as a progressive and devastating neurodegenerative disorder. In aged individuals, it is the most prevalent cause of dementia and is characterized by gradual loss of cognitive functions. In the last decade, numerous research works were undertaken to investigate the pathogenesis of AD. Although the etiology of AD is still not clear, several histopathological studies confirm prominent changes in the AD affected brains. The major changes include the formation of senile plaques and neurofibrillary tangles primarily owing to the deposition of amyloid β plaques (Aβ) and hyper-phosphorylation of tau protein. Disruption of the redox homeostasis in the brain is a major triggering factor for the development of such pathophysiological conditions. Chemical formulations usually act by inhibiting activities of the enzymes responsible for the development of AD. But with time, these pharmacotherapies develop many side effects including toxicity in different organs. Recent researches are henceforth focused on the identification of novel therapeutic molecules from the nature's basket. This review aims to emphasize the therapeutic effects and regulation of molecular targets of different natural products such as curcumin, resveratrol, genistein and others. These prophylactic multipotent natural compounds have the potency to interfere with the formation as well as deposition of the Aβ peptides. These natural compounds have also been found in modulating different intracellular signalling molecules and enzymes including β-secretase and γ-secretase. This review article is expected to be helpful in understanding the recent progress in natural product research as a therapeutic approach in amelioration and/or delaying the detrimental effects of AD.
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Affiliation(s)
- Pritam Sadhukhan
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata, 700054, India
| | - Sukanya Saha
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata, 700054, India
| | - Sayanta Dutta
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata, 700054, India
| | - Sushweta Mahalanobish
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata, 700054, India
| | - Parames C Sil
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata, 700054, India.
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38
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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: 120] [Impact Index Per Article: 17.1] [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.
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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.
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Eleftheriou A, Ulander M, Lundin F. Circadian rhythm in idiopathic normal pressure hydrocephalus. Clin Neurol Neurosurg 2017; 164:72-74. [PMID: 29202376 DOI: 10.1016/j.clineuro.2017.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/20/2017] [Accepted: 11/28/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The pathogenesis of idiopathic normal pressure hydrocephalus (iNPH) takes place in structures close to the cerebral ventricular system. Suprachiasmatic nucleus (SCN), situated close to the third ventricle, is involved in circadian rhythm. Diurnal disturbances are well-known in demented patients. The cognitive decline in iNPH is potentially reversible after a shunt operation. Diurnal rhythm has never been studied in iNPH. We hypothesize that there is a disturbance of circadian rhythm in iNPH-patients and the aim was to study any changes of the diurnal rhythm (mesor and circadian period) as well as any changes of the diurnal amplitude and acrophase of the activity in iNPH-patients before and after a shunt operation. PATIENTS AND METHODS Twenty consecutive iNPH-patients fulfilling the criteria of the American iNPH-guidelines, 9 males and 11 females, mean age 73 (49-81) years were included. The patients underwent a pre-operative clinical work-up including 10m walk time (w10mt) steps (w10ms), TUG-time (TUGt) and steps (TUGs) and for cognitive function an MMSE score was measured. In order to receive circadian rhythm data actigraphic recordings were performed using the SenseWear 2 (BodyMedia Inc Pittsburgh, PA, USA) actigraph. Cosinor analyses of accelerometry data were performed in "R" using non-linear regression with Levenburg- Marquardt estimation. Pre- and post-operative data regarding mesor, amplitude and circadian period were compared using Wilcoxon-Mann-Whitney test for paired data. RESULTS Twenty patients were evaluated before and three month post-operatively. Motor function (w10mt, w10ms, TUGt, TUGs) was significantly improved while MMSE was not significantly changed. Actigraphic measurements (mesor, amplitude and circadian period) showed no significant changes after shunt operation. CONCLUSION This is the first systematic study of circadian rhythm in iNPH-patients. We found no significant changes in circadian rhythm after shunt surgery. The conceptual idea of diurnal rhythm changes in hydrocephalus is still interesting from a theoretical standpoint and warrants further studies that could include a combination of better designed actigraphic studies in combination with neuroendocrine markers and imaging methods.
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Affiliation(s)
- Andreas Eleftheriou
- Department of Neurology, University Hospital, Linköping, Sweden; Department of Clinical and Experimental Medicine (IKE), Division of Neuroscience, Linköping University, Sweden.
| | - Martin Ulander
- Department of Clinical Neurophysiology, University Hospital, Linköping, Sweden; Department of Clinical and Experimental Medicine (IKE), Linköping University, Sweden
| | - Fredrik Lundin
- Department of Neurology, University Hospital, Linköping, Sweden; Department of Clinical and Experimental Medicine (IKE), Division of Neuroscience, Linköping University, Sweden
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Melatonin receptors: distribution in mammalian brain and their respective putative functions. Brain Struct Funct 2017; 222:2921-2939. [DOI: 10.1007/s00429-017-1439-6] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/28/2017] [Indexed: 12/15/2022]
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Pinato L, Ramos D, Hataka A, Rossignoli PS, Granado MD, Mazzetto MC, Campos LMG. Day/night expression of MT 1 and MT 2 receptors in hypothalamic nuclei of the primate Sapajus apella. J Chem Neuroanat 2017; 81:10-17. [PMID: 28159659 DOI: 10.1016/j.jchemneu.2017.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 01/29/2017] [Accepted: 01/30/2017] [Indexed: 12/19/2022]
Abstract
Melatonin is involved in the temporal organization of several physiological and behavioral events, controlled by hypothalamic nuclei, like sleep, feeding, reproduction and metabolic modulation and acts through two types of high-affinity G protein-coupled membrane receptors: MT1 and MT2. This study aimed to investigate the expression of MT1 and MT2 receptors proteins in four hypothalamic nuclei, i.e., SCN, supraoptic (SON), paraventricular (PVN) and anteroventral periventricular nuclei (AVPV), of the diurnal primate Sapajus apella using immunohistochemistry. Since these areas are involved in the expression of biological rhythms, they are candidates to have variations in their neurochemistry, so the MT1 and MT2 expression has been analyzed at a point in light and another in the dark phase. Both receptors were found to have day/night differences in the four hypothalamic nuclei with an apparent inverse expression in the SCN compared with the other areas. These differences could be related to the idea that the individual should be prepared to respond by different ways to melatonin signal within the several processes and can contribute to the efficacy of melatonin ligands or melatonin in therapies.
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Affiliation(s)
| | - Dayane Ramos
- University of Marilia (UNIMAR), Medical School, Marilia, SP, Brazil
| | | | | | | | | | - Leila M G Campos
- São Paulo State University (UNESP), Marilia, SP, Brazil; University of Marilia (UNIMAR), Medical School, Marilia, SP, Brazil.
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Pévet P. Melatonin receptors as therapeutic targets in the suprachiasmatic nucleus. Expert Opin Ther Targets 2016; 20:1209-18. [DOI: 10.1080/14728222.2016.1179284] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Paul Pévet
- Institut des neurosciences cellulaires et Integratives, INCI UPR 3212, CNRS and the University of Strasbourg, Strasbourg, France
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