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melatonin acrophase

Shuhui Ma, Zixu Wang, Jing Cao, Yulan Dong, Yaoxing Chen
The avian circadian system is a complex of mutually coupled pacemakers residing in pineal gland, retina and suprachiasmatic nucleus. In this study, the self-regulation mechanism of pineal circadian rhythm was investigated by culturing chick primary pinealocytes exposed to red light (RL), green light (GL), blue light (BL), white light (WL) and constant darkness (DD), respectively. All illuminations were set up with a photoperiod of 12 light: 12 dark. The 24-h expression profiles of seven core clock genes (cBmal1/2, cClock, cCry1/2, and cPer2/3), cAanat and melatonin showed significant circadian oscillation in all groups, except for the loss of cCry1 rhythm in BL...
June 13, 2018: Photochemistry and Photobiology
Jia Song, Shuaishuai Chu, Yin Cui, Yue Qian, Xiuxiu Li, Fangxia Xu, Xueming Shao, Zhengliang Ma, Tianjiao Xia, Xiaoping Gu
Postoperative cognitive dysfunction (POCD) is a common clinical phenomenon characterized by cognitive deficits in patients after anesthesia and surgery. Advanced age is a significant independent risk factor for POCD. We previously reported that in young mice, sleep-wake rhythm is involved in the isoflurane-induced memory impairment. In present study, we sought to determine whether advanced age increased the risk of POCD through aggravated and prolonged post-anesthetic circadian disruption in the elderly. We constructed POCD model by submitting the mice to 5-h 1...
August 2018: Experimental Neurology
Catarina C V Oliveira, Filipe Figueiredo, Florbela Soares, Wilson Pinto, Maria Teresa Dinis
The present study reveals the first characterization of the plasma melatonin rhythms of the meagre (Argyrosomus regius) under aquaculture conditions. Melatonin levels were monitored during a 24 h cycle under a photoperiod of 16 L:8D and under constant darkness (DD), respectively to characterize the daily rhythm of this indoleamine and to test its endogenous origin. Besides, to identify which light intensities are perceived as night or day by this species, the degree of inhibition of nocturnal melatonin production caused by increasing intensities of light was tested (3...
June 2018: Fish Physiology and Biochemistry
Romesh G Abeysuriya, Steven W Lockley, Peter A Robinson, Svetlana Postnova
A biophysical model of the key aspects of melatonin synthesis and excretion has been developed, which is able to predict experimental dynamics of melatonin in plasma and saliva, and of its urinary metabolite 6-sulfatoxymelatonin (aMT6s). This new model is coupled to an established model of arousal dynamics, which predicts sleep and circadian dynamics based on light exposure and times of wakefulness. The combined model thus predicts melatonin levels over the sleep-wake/dark-light cycle and enables prediction of melatonin-based circadian phase markers, such as dim light melatonin onset (DLMO) and aMT6s acrophase under conditions of normal sleep and circadian misalignment...
May 2018: Journal of Pineal Research
Melissa A St Hilaire, Shadab A Rahman, Joshua J Gooley, Paula A Witt-Enderby, Steven W Lockley
Although evidence exists for a daily rhythm in bone metabolism, the contribution of factors such as melatonin levels, the light-dark cycle, and the sleep-wake cycle is difficult to differentiate given their highly correlated time courses. To examine these influences on bone resorption, we collected 48-h sequential urine samples under both ambulatory (8-h sleep:16-h wake) and constant routine (CR) (constant wake, posture, nutrition and dim light) conditions from 20 healthy premenopausal women. Urinary 6-sulphatoxymelatonin (aMT6s; ng/h) and the bone resorption marker amino-terminal cross-linked collagen I telopeptide (NTx; bone collagen equivalents nM/h) were assayed and fit by cosinor models to determine significant 24-h rhythms and acrophase...
January 9, 2018: Journal of Bone and Mineral Metabolism
Tara S Rogers, Stephanie Harrison, Christine Swanson, Jane A Cauley, Elizabeth Barrett-Connor, Eric Orwoll, Katie L Stone, Nancy E Lane
Background: Disrupted rest-activity circadian rhythm (RAR) patterns have been associated with poor health outcomes (i.e. diminished cognitive function, increased risk of dementia and falls). Circadian time cues in bone influence the differentiation of osteoblasts and osteoclasts, and bone turnover markers exhibit circadian variation; relationships between bone outcomes and RAR are emerging areas of research. We evaluated associations between RAR and areal bone mineral density (aBMD) at the total hip and femoral neck in older men from the Osteoporotic Fractures in Men (MrOS) cohort...
December 2017: Bone Reports
Ana Checa-Ros, Antonio Muñoz-Gallego, María de Los Ángeles Muñoz-Gallego, Antonio Molina-Carballo, Susana Narbona-Galdó, Antonio Jeréz-Calero, María Del Carmen Augustín-Morales, Antonio Muñoz-Hoyos
BACKGROUND AND OBJECTIVES: Despite the numerous investigations carried out in relation to melatonin, there is a lack of knowledge about the specific melatonin secretion patterns in the diverse primary sleep disturbances. The objective of this study was to analyze the plasma melatonin concentrations in children with primary sleep disorders and the effects of melatonin therapy on their serum levels and their actigraphic sleep parameters. METHODS: Fourteen participants (nine girls; seven to 14 years old) diagnosed with diverse primary sleep disorders were recruited...
January 2018: Pediatric Neurology
Aljohara S Almeneessier, Ahmed S Bahammam, Munir M Sharif, Salman A Bahammam, Samar Z Nashwan, Seithikurippu R Pandi Perumal, Daniel P Cardinali, Mohammad Alzoghaibi
AIMS: We hypothesized that if we control for food composition, caloric intake, light exposure, sleep schedule, and exercise, intermittent fasting would not influence the circadian pattern of melatonin. Therefore, we designed this study to assess the effect of intermittent fasting on the circadian pattern of melatonin. METHODS: Eight healthy volunteers with a mean age of 26.6 ± 4.9 years and body mass index of 23.7 ± 3.5 kg/m2 reported to the Sleep Disorders Center (the laboratory) on four occasions: (1) adaptation, (2) 4 weeks before Ramadan while performing Islamic intermittent fasting for 1 week (fasting outside Ramadan [FOR]), (3) 1 week before Ramadan (nonfasting baseline [BL]), and (4) during the 2nd week of Ramadan while fasting ( Ramadan )...
July 2017: Annals of Thoracic Medicine
Lydiane Aubè, Meriem Fatnassi, Davide Monaco, Touhami Khorchani, Giovanni Michele Lacalandra, Mohamed Hammadi, Barbara Padalino
BACKGROUND: Daily rhythmicity has been observed for a number of hormonal and behavioral variables in mammals. It can be entrained by several external factors, such as light-dark cycle and scheduled feeding. In dromedary camels, daily rhythmicity has been documented only for melatonin secretion and body temperature. In this study, the daily rhythmicity of behavioral repertoire, cortisol and testosterone levels was investigated in captive male camels. METHODS: Six clinically healthy male dromedary camels ( Camelus dromedarius ) were used...
2017: PeerJ
Nan Jiang, Zixu Wang, Jing Cao, Yulan Dong, Yaoxing Chen
The avian pineal gland is a master clock that can receive external photic cues and translate them into output rhythms. To clarify whether a shift in light wavelength can influence the circadian expression in chick pineal gland, a total of 240 Arbor Acre male broilers were exposed to white light (WL), red light (RL), green light (GL) or blue light (BL). After 2weeks light illumination, circadian expressions of seven core clock genes in pineal gland and the level of melatonin in plasma were examined. The results showed after illumination with monochromatic light, 24h profiles of all clock gene mRNAs retained circadian oscillation, except that RL tended to disrupt the rhythm of cCry2...
November 2016: Journal of Photochemistry and Photobiology. B, Biology
Caroline Luísa Quiles, Melissa Alves Braga de Oliveira, André Comiran Tonon, Maria Paz Loayza Hidalgo
3A substantial amount of experimental models designed to understand rhythms entrainment and the effects of different regimens of light exposure on health have been proposed. However, many of them do not relate to what occurs in real life. Our objective was to evaluate the influence of "seasonal-like" variation in light/dark cycles on biological rhythms. Twenty adult male Wistar rats were assigned to three groups: control (CT), kept in 12:12 light/dark (LD) cycle; long photoperiod/short photoperiod (LP/SP), kept in 16...
2016: Chronobiology International
Zeeshan Ahmad Khan, Thangal Yumnamcha, Chongtham Rajiv, Haobijam Sanjita Devi, Gopinath Mondal, Sh Dharmajyoti Devi, Rupjyoti Bharali, Asamanja Chattoraj
The present study on zebrafish (Danio rerio) is the first attempt to demonstrate the circadian mRNA expression of melatonin biosynthesizing enzyme genes (Tph1a, Aanat1, Aanat2 and Hiomt) and clock associated genes (Bmal1a, Clock1a, Per1b, Per2 and Cry2a) in the ovary with a comparison to whole brain in normal (LD=12h L:12h D) and altered photic conditions (continuous dark, DD; continuous light, LL). Moreover, the present study also confirmed the ability of zebrafish ovary to biosynthesize melatonin both in vivo and in vitro with a significant difference at day and night...
July 1, 2016: General and Comparative Endocrinology
Sourav Mukherjee, Saumen Kumar Maitra
Influences of starvation, re-feeding and time of food supply on daily rhythm features of melatonin (5-methoxy-N-acetyltryptamine) and its key regulator AANAT (arylalkylamine N-acetyltransferase) protein in the gut tissues were separately evaluated in carp Catla catla. The first experiment was aimed at demonstration of duration dependent effects of starvation and re-feeding after starvation on the daily profiles and rhythm features of gut melatonin and AANAT. Accordingly, juvenile carp were randomly distributed in three groups, which were (a) provided with balanced diet daily at a fixed time, that is, 10:00 clock hour or zeitgeber time (ZT) 4 (control), or (b) starved (for 2-, 4-, 6- or 8 days), or (c) initially starved for 8 days and then re-fed (for 2-, 4-, 6-, 8-, 12- or 16 days) daily with the same food and at the time (ZT4) used for control fish...
2015: Chronobiology International
Roberto C Leonardo-Mendonça, Antonio Martinez-Nicolas, Carlos de Teresa Galván, Javier Ocaña-Wilhelmi, Iryna Rusanova, Eduardo Guerra-Hernández, Germaine Escames, Darío Acuña-Castroviejo
Exercise can induce circadian phase shifts depending on the duration, intensity and frequency. These modifications are of special meaning in athletes during training and competition. Melatonin, which is produced by the pineal gland in a circadian manner, behaves as an endogenous rhythms synchronizer, and it is used as a supplement to promote resynchronization of altered circadian rhythms. In this study, we tested the effect of melatonin administration on the circadian system in athletes. Two groups of athletes were treated with 100 mg day(-1) of melatonin or placebo 30 min before bed for four weeks...
2015: Chronobiology International
Gorica Micic, Nicole Lovato, Michael Gradisar, Helen J Burgess, Sally A Ferguson, David J Kennaway, Leon Lack
A significant delay in the timing of endogenous circadian rhythms has been associated with delayed sleep phase disorder (DSPD). More recently, other mechanisms have also been proposed to account for this disorder. To further explore the etiology of DSPD, the present study compared nocturnal melatonin profiles of 26 DSPD patients (18 males, 8 females; age, 21.73 ± 4.98 years) and 17 normally timed good sleepers (10 males, 7 females; age, 23.82 ± 5.23 years) in a time-free, dim-light (<10 lux) laboratory environment...
October 2015: Journal of Biological Rhythms
Angela M Ramos-Lobo, Daniella C Buonfiglio, José Cipolla-Neto
BACKGROUND: In mammals, the temperature rhythm is regulated by the circadian pacemaker located in the suprachiasmatic nuclei, and is considered a "marker rhythm". Melatonin, the pineal gland hormone, is a major regulator of the endogenous rhythms including body temperature. Its production is influenced by many factors, such as type 1 diabetes mellitus. In rats, diabetes leads to hypothermia and reduced melatonin synthesis; insulin treatment reestablishes both. AIM: To study the body temperature daily rhythm of diabetic animals and the effects of insulin and/or melatonin treatment on its structure...
2015: Diabetology & Metabolic Syndrome
M A Bonmati-Carrion, B Middleton, V L Revell, D J Skene, M A Rol, J A Madrid
Since there is less movement during sleep than during wake, the recording of body movements by actigraphy has been used to indirectly evaluate the sleep-wake cycle. In general, most actigraphic devices are placed on the wrist and their measures are based on acceleration detection. Here, we propose an alternative way of measuring actigraphy at the level of the arm for joint evaluation of activity and body position. This method analyzes the tilt of three axes, scoring activity as the cumulative change of degrees per minute with respect to the previous sampling, and measuring arm tilt for the body position inference...
June 2015: Chronobiology International
Francine Harb, Maria Paz Hidalgo, Betina Martau
The diurnal light cycle has a crucial influence on all life on earth. Unfortunately, modern society has modified this life-governing cycle by stressing maximum production and by giving insufficient attention to the ecological balance and homeostasis of the human metabolism. The aim of this study is to evaluate the effects of exposure or lack of exposure to natural light in a rest/activity rhythm on cortisol and melatonin levels, as well as on psychological variables in humans under natural conditions. This is a cross-sectional study...
April 2015: Chronobiology International
Inés Gómez-Acebo, Trinidad Dierssen-Sotos, Kyriaki Papantoniou, María Teresa García-Unzueta, María Francisca Santos-Benito, Javier Llorca
The present study aims to compare 6-sulfatoxymelatonin (aMT6s) secretion patterns and levels of cortisol and sex hormones (estradiol, progesterone, DHEA, DHEAS, and testosterone) among rotating night-shift workers and day-shift workers. We performed a cross-sectional study in Cantabria (northern Spain) including 136 women (73 day-shift workers and 63 rotating night-shift workers). Blood and urine samples were obtained after two consecutive working days. Differences in means were estimated using ANCOVA, stratified by menopausal status, ovulation phase, and adjusted for season, age, body mass index, consumption of cigarettes in the last 24 h...
February 2015: Chronobiology International
Eirini Kalliolia, Edina Silajdžić, Rajasree Nambron, Nathan R Hill, Anisha Doshi, Chris Frost, Hilary Watt, Peter Hindmarsh, Maria Björkqvist, Thomas T Warner
This study was undertaken to determine whether the production of melatonin, a hormone regulating sleep in relation to the light/dark cycle, is altered in Huntington's disease. We analyzed the circadian rhythm of melatonin in a 24-hour study of cohorts of control, premanifest, and stage II/III Huntington's disease subjects. The mean and acrophase melatonin concentrations were significantly reduced in stage II/III Huntington's disease subjects compared with controls. We also observed a nonsignificant trend toward reduced mean and acrophase melatonin in premanifest Huntington's disease subjects...
October 2014: Movement Disorders: Official Journal of the Movement Disorder Society
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