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1

Nocturnal cortisol and melatonin secretion in primary insomnia.  

Science.gov (United States)

The present study investigated evening and nocturnal serum cortisol and melatonin concentrations in patients with primary insomnia to test if this clinical condition is accompanied by an increase of cortisol secretion and a simultaneous decrease of nocturnal melatonin production. Ten drug-free patients (4 males, 6 females) with primary insomnia (mean age+/-S.D.: 39.2+/-9.1 years) and 10 age- and gender-matched healthy controls participated in the study. All subjects spent three consecutive nights in the sleep laboratory with polysomnography. Measurement of cortisol and melatonin (from 19:00 h to 09:00 h) was performed prior to and during the last laboratory night. Contrary to expectation, cortisol secretion did not differ between healthy controls and insomniac patients. On the other hand, nocturnal melatonin production was significantly diminished in insomniac patients. Polysomnographically determined sleep patterns, in contrast to subjective ratings of sleep, demonstrated only minor alterations of sleep in the insomniac group. The lack of increased cortisol secretion in the patients with primary insomnia indicates that results from studies on the biological consequences of experimental sleep loss in healthy subjects cannot be applied to primary insomnia in general, especially if there are only minor objective sleep alterations. In spite of the negligible objective sleep disturbances in the present sample, nocturnal melatonin production was reduced, which tentatively suggests a role for this hormone in primary insomniacs. The pathophysiological significance of this finding is, however, still a matter of debate. PMID:12467942

Riemann, Dieter; Klein, Torsten; Rodenbeck, Andrea; Feige, Bernd; Horny, Andrea; Hummel, Ruth; Weske, Gesa; Al-Shajlawi, Anam; Voderholzer, Ulrich

2002-12-15

2

Local corticosterone infusion enhances nocturnal pineal melatonin production in vivo.  

Science.gov (United States)

Melatonin, an important marker of the endogenous rhythmicity in mammals, also plays a role in the body defence against pathogens and injuries. In vitro experiments have shown that either pro- or anti-inflammatory agents, acting directly in the organ, are able to change noradrenaline-induced pineal indoleamine production. Whereas corticosterone potentiates melatonin production, incubation of the gland with tumour necrosis factor-alpha decreases pineal hormonal production. In the present study, we show that nocturnal melatonin production measured by intra-pineal microdialysis is enhanced in pineals perfused with corticosterone at concentrations similar to those measured in inflamed animals. In vitro experiments suggest that this enhancement may be due to an increase in the activity of the two enzymes that convert serotonin to N-acetylserotonin (NAS) and NAS to melatonin. The present results support the hypothesis that the pineal gland is a sensor of inflammation mediators and that it plays a central role in the control of the inflammatory response. PMID:19076264

Fernandes, P A C M; Bothorel, B; Clesse, D; Monteiro, A W A; Calgari, C; Raison, S; Simonneaux, V; Markus, R P

2009-02-01

3

Interplay among nocturnal activity, melatonin, corticosterone and performance in the invasive cane toad (Rhinella marinus).  

Science.gov (United States)

Most animals conduct daily activities exclusively either during the day or at night. Here, hormones such as melatonin and corticosterone, greatly influence the synchronization or regulation of physiological and behavioral cycles needed for daily activity. How then do species that exhibit more flexible daily activity patterns, responses to ecological, environmental or life-history processes, regulate daily hormone profiles important to daily performance? This study examined the consequences of (1) nocturnal activity on diel profiles of melatonin and corticosterone and (2) the effects of experimentally increased acute melatonin levels on physiological and metabolic performance in the cane toad (Rhinella marinus). Unlike inactive captive toads that had a distinct nocturnal melatonin profile, nocturnally active toads sampled under field and captive conditions, exhibited decreased nocturnal melatonin profiles with no evidence for any phase shift. Nocturnal corticosterone levels were significantly higher in field active toads than captive toads. In toads with experimentally increased melatonin levels, plasma lactate and glucose responses following recovery post exercise were significantly different from control toads. However, exogenously increased melatonin did not affect resting metabolism in toads. These results suggest that toads could adjust daily hormone profiles to match nocturnal activity requirements, thereby avoiding performance costs induced by high nocturnal melatonin levels. The ability of toads to exhibit plasticity in daily hormone cycles, could have broad implications for how they and other animals utilize behavioral flexibility to optimize daily activities in response to natural and increasingly human mediated environmental variation. PMID:25063397

Jessop, Tim S; Dempster, Tim; Letnic, Mike; Webb, Jonathan K

2014-09-15

4

Effect of melatonin on nocturnal blood pressure: meta-analysis of randomized controlled trials  

Directory of Open Access Journals (Sweden)

Full Text Available Ehud Grossman1,4, Moshe Laudon2, Nava Zisapel2,31Department of Internal Medicine D and Hypertension Unit, The Chaim Sheba Medical Center, Tel-Hashomer, Israel; 2Neurim Pharmaceuticals Ltd, Tel Aviv, Israel and 3Department of Neurobiology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; 4Sackler School of Medicine, Tel Aviv University, Tel Aviv, IsraelBackground: Patients with nocturnal hypertension are at higher risk for cardiovascular complications such as myocardial infarction and cerebrovascular insult. Published studies inconsistently reported decreases in nocturnal blood pressure with melatonin.Methods: A meta-analysis of the efficacy and safety of exogenous melatonin in ameliorating nocturnal blood pressure was performed using a random effects model of all studies fitting the inclusion criteria, with subgroup analysis of fast-release versus controlled-release preparations.Results: Seven trials (three of controlled-release and four of fast-release melatonin with 221 participants were included. Meta-analysis of all seven studies did not reveal significant effects of melatonin versus placebo on nocturnal blood pressure. However, subgroup analysis revealed that controlled-release melatonin significantly reduced nocturnal blood pressure whereas fast-release melatonin had no effect. Systolic blood pressure decreased significantly with controlled-release melatonin (-6.1 mmHg; 95% confidence interval [CI] -10.7 to -1.5; P = 0.009 but not fast-release melatonin (-0.3 mmHg; 95% CI -5.9 to 5.30; P = 0.92. Diastolic blood pressure also decreased significantly with controlled-release melatonin (-3.5 mmHg; 95% CI -6.1 to -0.9; P = 0.009 but not fast-release melatonin (-0.2 mmHg; 95% CI -3.8 to 3.3; P = 0.89. No safety concerns were raised.Conclusion: Add-on controlled-release melatonin to antihypertensive therapy is effective and safe in ameliorating nocturnal hypertension, whereas fast-release melatonin is ineffective. It is necessary that larger trials of longer duration be conducted in order to determine the long-term beneficial effects of controlled-release melatonin in patients with nocturnal hypertension.Keywords: melatonin, nocturnal blood pressure, meta-analysis 

Grossman E

2011-09-01

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Nocturnal headache associated with melatonin deficiency due to a pineal gland cyst.  

Science.gov (United States)

The cyclic nature of some of headache disorders is closely related to melatonin, which is secreted by the pineal gland. We report a 29-year-old male patient with a 2.5-year history of headaches that woke him in the middle of the night. These headaches were pulsatile and continued until sunrise. During these attacks he also suffered from allodynia over the scalp, bilateral conjunctival hyperemia, and nervousness. His brain MRI showed a 5mm by 4mm neuroepithelial cyst in the pineal gland. The peak plasma melatonin level that was measured at 2 am was 28 pg/mL. The patient underwent oral melatonin treatment (6 mg/day). After 1 month he experienced a 70% reduction in his symptoms. When the melatonin dosage was increased to 10mg/day he became headache-free, and 5 months after the treatment began, had no complaints. His 5-month follow-up plasma melatonin level at 2 am was 61 pg/mL. To our knowledge this is the first report of a patient with nocturnal headache associated with a low level of melatonin due to a neuroepithelial cyst in the pineal gland. PMID:22136735

Karada?, Omer; Ipekdal, Ilker H; Ula?, Umit H; Odaba?i, Zeki

2012-02-01

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Transcranial bright light exposure via ear canals does not suppress nocturnal melatonin in healthy adults--a single-blind, sham-controlled, crossover trial.  

Science.gov (United States)

We investigated whether transcranial bright light (TBL) affects nocturnal melatonin and cortisol secretion in sham-controlled crossover trial. Young healthy adults were exposed in random order to 24 minutes of TBL or sham exposure via ear canals at 01:10?h. Saliva and urine samples were collected hourly between 21?h-03?h and 06?h-09?h. There were no significant differences in melatonin or cortisol concentrations between TBL and sham exposures at any sampling point indicating that TBL via ear canals does not suppress nocturnal melatonin secretion. Thus, non-visual effects of TBL are mediated via a pathway not involving melatonin suppression. PMID:24828616

Jurvelin, Heidi; Takala, Timo; Heberg, Lilli; Nissilä, Juuso; Rüger, Melanie; Leppäluoto, Juhani; Saarela, Seppo; Vakkuri, Olli

2014-08-01

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The flavonoid myricetin reduces nocturnal melatonin levels in the blood through the inhibition of serotonin N-acetyltransferase.  

Science.gov (United States)

Melatonin is secreted during the hours of darkness and is thought to influence the circadian and seasonal timing of a variety of physiological processes. AANAT, which is expressed in the pineal gland, retina, and various other tissues, catalyzes the conversion of serotonin to N-acetylserotonin and is the rate-limiting enzyme in the biosynthetic pathway of melatonin. The compounds that modulate the activity of AANAT can be used to treat patients with circadian rhythm disorders that are associated with specific circadian rhythm alterations, such as shift work disorder. In the present study, we screened modulators of AANAT activity from the water extracts of medicinal plants. Among the 267 tested medicinal plant extracts, Myricae Cortex (Myrica rubra), Perillae Herba (Perilla sikokiana), and Eriobotryae Folium (Eriobotrya japonica) showed potent inhibition of AANAT activity. Myricetin (5,7,3',4',5'-pentahydroxyflavonol), a main component of the Myricae Cortex, strongly inhibited the activity of AANAT and probably block the access to the substrate by docking to the catalytic residues that are important for AANAT activity. Myricetin significantly decreased the nocturnal serum melatonin levels in rats. In addition, the locomotor activity of rats treated with myricetin decreased during the nighttime and slightly increased throughout the day. These results suggest that myricetin could be used as a therapy to increase nighttime alertness by changing the circadian rhythm of serum melatonin and locomotor activity. PMID:24076393

Shin, Jae-Cheon; Jung, Hoe-Yune; Harikishore, Amaravadhi; Kwon, Oh-Deog; Yoon, Ho Sup; Kim, Kyong-Tai; Choi, Bo-Hwa

2013-10-18

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Alteraciones de la secreción nocturna de melatonina y neuropatías ópticas / Alterations in nocturnal melatonin levels in patients with optic neuropathies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Objetivo: Evaluar la supresión de la secreción nocturna de melatonina inducida por exposición a la luz en pacientes con neuropatías ópticas bilaterales. Métodos: Estudio clínico de casos controles, observacional y prospectivo. Tamaño muestral de 20 pacientes distribuidos en 3 grupos: Grupo A (n=5, S [...] ujetos Sanos Controles), Grupo B (n=10, Pacientes Experimentales) y Grupo C (n=5, Sujetos Controles Ciegos). Se analiza la mejor agudeza visual corregida LogMAR, la desviación media en perimetría estática automatizada, el espesor medio de la capa de fibras nerviosas retinianas mediante Tomografía de Coherencia Óptica y los registros de electrorretinografía multifocal (mfERG). Se realizan determinaciones de melatonina en saliva por radioinmunoensayo tras exposición a una luz de 600 lux durante 1 hora (Test de supresión nocturna de melatonina). Resultados: Se encontraron diferencias estadísticamente significativas entre los grupos. No se observaron cambios en los registros de mf ERG. El test de supresión nocturna de melatonina fue positivo en todos los casos del Grupo A, en el 50% de los casos del Grupo B y en todos los casos del Grupo C fue negativo. Conclusiones: El 50% de los pacientes con neuropatías ópticas y pérdida visual severa exhiben alteraciones significativas en la secreción nocturna de melatonina, probablemente debido a una disfunción de las células ganglionares de la retina intrínsecamente fotosensibles (ipCGR). Abstract in english Objective: To study nocturnal melatonin suppression induced by exposure to light in patients with bilateral optic neuropathies. Methods: Observational, prospective case control study. Twenty patients were included in this study and distributed in 3 groups: Group A (n=5, Healthy Control Subjects), Gr [...] oup B (n=10, Experimental Patients) and Group C (n=5, Blind Control Subjects). LogMAR best-corrected visual acuity, standard automated perimetry mean deviation, retinal nerve fiber layer thickness by Optical Coherence Tomography and multifocal electroretinograpy (mfERG) were used to evaluate the changes. Melatonin was analysed in the saliva by radioimmunoassay after exposure to light (600 lux for 1 hour) (nocturnal melatonin suppression test). Results: Statistically significant differences between the groups were found. No changes in the mfERG results were detected. The nocturnal melatonin suppression test was positive in all cases in Group A, 50 % in Group B and none in Group C. Conclusions: Half of the patients with optic neuropathies and severe visual loss were shown to suffer significant melatonin regulation anomalies, probably due to the dysfunction of the intrinsically photosensitive retinal ganglion cells (ipRGC).

C., Pérez-Rico; P., De la Villa; R., Blanco; F., Germain; J., Paz-Moreno; I., Arribas-Gómez.

9

Alteraciones de la secreción nocturna de melatonina y neuropatías ópticas / Alterations in nocturnal melatonin levels in patients with optic neuropathies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Spain | Language: Spanish Abstract in spanish Objetivo: Evaluar la supresión de la secreción nocturna de melatonina inducida por exposición a la luz en pacientes con neuropatías ópticas bilaterales. Métodos: Estudio clínico de casos controles, observacional y prospectivo. Tamaño muestral de 20 pacientes distribuidos en 3 grupos: Grupo A (n=5, S [...] ujetos Sanos Controles), Grupo B (n=10, Pacientes Experimentales) y Grupo C (n=5, Sujetos Controles Ciegos). Se analiza la mejor agudeza visual corregida LogMAR, la desviación media en perimetría estática automatizada, el espesor medio de la capa de fibras nerviosas retinianas mediante Tomografía de Coherencia Óptica y los registros de electrorretinografía multifocal (mfERG). Se realizan determinaciones de melatonina en saliva por radioinmunoensayo tras exposición a una luz de 600 lux durante 1 hora (Test de supresión nocturna de melatonina). Resultados: Se encontraron diferencias estadísticamente significativas entre los grupos. No se observaron cambios en los registros de mf ERG. El test de supresión nocturna de melatonina fue positivo en todos los casos del Grupo A, en el 50% de los casos del Grupo B y en todos los casos del Grupo C fue negativo. Conclusiones: El 50% de los pacientes con neuropatías ópticas y pérdida visual severa exhiben alteraciones significativas en la secreción nocturna de melatonina, probablemente debido a una disfunción de las células ganglionares de la retina intrínsecamente fotosensibles (ipCGR). Abstract in english Objective: To study nocturnal melatonin suppression induced by exposure to light in patients with bilateral optic neuropathies. Methods: Observational, prospective case control study. Twenty patients were included in this study and distributed in 3 groups: Group A (n=5, Healthy Control Subjects), Gr [...] oup B (n=10, Experimental Patients) and Group C (n=5, Blind Control Subjects). LogMAR best-corrected visual acuity, standard automated perimetry mean deviation, retinal nerve fiber layer thickness by Optical Coherence Tomography and multifocal electroretinograpy (mfERG) were used to evaluate the changes. Melatonin was analysed in the saliva by radioimmunoassay after exposure to light (600 lux for 1 hour) (nocturnal melatonin suppression test). Results: Statistically significant differences between the groups were found. No changes in the mfERG results were detected. The nocturnal melatonin suppression test was positive in all cases in Group A, 50 % in Group B and none in Group C. Conclusions: Half of the patients with optic neuropathies and severe visual loss were shown to suffer significant melatonin regulation anomalies, probably due to the dysfunction of the intrinsically photosensitive retinal ganglion cells (ipRGC).

C., Pérez-Rico; P., De la Villa; R., Blanco; F., Germain; J., Paz-Moreno; I., Arribas-Gómez.

2009-05-01

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Reduction of the nocturnal rise in pineal melatonin levels in rats exposed to 60-Hz electric fields in utero and for 23 days after birth  

International Nuclear Information System (INIS)

Rats exposed to 60-Hz electric fields of either 10, 65, or 130 kV/m from conception to 23 days of age exhibited reduced peak nighttime pineal melatonin contents compared to unexposed controls. As a group, the exposed rats also exhibited a phase delay, estimated at approximately 1.4 hours, in the occurrence of the nocturnal melatonin peak. No clear dose-response relationship was noticed over the range of electric field strengths used as treatments in these experiments. These are the first studies concerned with the effects of electric field exposure on the pineal melatonin rhythm in immature rats and the findings are generally consistent with those obtained using adult rats, where electric field exposure has been shown to abolish the nighttime rhythm in pineal melatonin concentrations. 15 refs., 1 fig., 1 tab

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Reduction of the nocturnal rise in pineal melatonin levels in rats exposed to 60-Hz electric fields in utero and for 23 days after birth  

Energy Technology Data Exchange (ETDEWEB)

Rats exposed to 60-Hz electric fields of either 10, 65, or 130 kV/m from conception to 23 days of age exhibited reduced peak nighttime pineal melatonin contents compared to unexposed controls. As a group, the exposed rats also exhibited a phase delay, estimated at approximately 1.4 hours, in the occurrence of the nocturnal melatonin peak. No clear dose-response relationship was noticed over the range of electric field strengths used as treatments in these experiments. These are the first studies concerned with the effects of electric field exposure on the pineal melatonin rhythm in immature rats. The findings are generally consistent with those obtained using adult rats, where electric field exposure has been shown to abolish the nighttime rhythm in pineal melatonin concentrations.

Reiter, R.J.; Anderson, L.E.; Buschbom, R.L.; Wilson, B.W.

1988-01-01

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Reduction of the nocturnal rise in pineal melatonin levels in rats exposed to 60-Hz electric fields in utero and for 23 days after birth  

Energy Technology Data Exchange (ETDEWEB)

Rats exposed to 60-Hz electric fields of either 10, 65, or 130 kV/m from conception to 23 days of age exhibited reduced peak nighttime pineal melatonin contents compared to unexposed controls. As a group, the exposed rats also exhibited a phase delay, estimated at approximately 1.4 hours, in the occurrence of the nocturnal melatonin peak. No clear dose-response relationship was noticed over the range of electric field strengths used as treatments in these experiments. These are the first studies concerned with the effects of electric field exposure on the pineal melatonin rhythm in immature rats and the findings are generally consistent with those obtained using adult rats, where electric field exposure has been shown to abolish the nighttime rhythm in pineal melatonin concentrations. 15 refs., 1 fig., 1 tab.

Reiter, R.J.; Anderson, L.E.; Buschbom, R.I.; Wilson, B.W.

1988-02-01

13

Rapid-onset/offset, variably scheduled 60 Hz electric and magnetic field exposure reduces nocturnal serum melatonin concentration in nonhuman primates  

Energy Technology Data Exchange (ETDEWEB)

Experiments with rodents indicate that power-frequency electric field (EF) or magnetic field (MF) exposure can suppress the normal nocturnal increase in melatonin concentration in pineal gland and blood. In a separate set of three experiments conducted with nonhuman primates, the authors did not observe melatonin suppression as a result of 6 weeks of day-time exposure to combined 60 Hz electric and magnetic fields (E/MF) with regularly schedule ``slow`` E/MF onsets/offsets. The study described here used a different exposure paradigm in which two baboons were exposed to E/MF with ``rapid`` E/MF onsets/offsets accompanied by EF transients not found with slowly ramped E/MF onset/offset; profound reductions in nocturnal serum melatonin concentration were observed in this experiment. If replicated in a more extensive experiment, the observation of melatonin suppression only in the presence of E/MF transients would suggest that very specific exposure parameters determine the effects of 60 Hz E/MF on melatonin.

Rogers, W.R.; Smith, H.D. [Southwest Research Inst., San Antonio, TX (United States). Dept. of Biosciences and Bioengineering; Reiter, R.J.; Barlow-Walden, L. [Univ. of Texas Health Science Center, San Antonio, TX (United States). Dept. of Cellular and Structural Biology

1995-12-31

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Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans.  

Science.gov (United States)

Melatonin and serotonin rhythms, which exhibit a close association with the endogenous circadian component of sleep, are attenuated with increasing age. This decrease seems to be linked to sleep alterations in the elderly. Chrononutrition is a field of chronobiology that establishes the principle of consuming foodstuffs at times of the day when they are more useful for health, improving, therefore, biorhythms and physical performance. Our aim was to analyze whether the consumption of cereals enriched with tryptophan, the precursor of both serotonin and melatonin, may help in the reconsolidation of the sleep/wake cycle and counteract depression and anxiety in 35 middle-aged/elderly (aged 55-75 year) volunteers in a simple blind assay. Data were collected for 3 weeks according to the following schedule: The control week participants consumed standard cereals (22.5 mg tryptophan in 30 g cereals per dose) at breakfast and dinner; for the treatment week, cereals enriched with a higher dose of tryptophan (60 mg tryptophan in 30 g cereals per dose) were eaten at both breakfast and dinner; the posttreatment week volunteers consumed their usual diet. Each participant wore a wrist actimeter that logged activity during the whole experiment. Urine was collected to analyze melatonin and serotonin urinary metabolites and to measure total antioxidant capacity. The consumption of cereals containing the higher dose in tryptophan increased sleep efficiency, actual sleep time, immobile time, and decreased total nocturnal activity, sleep fragmentation index, and sleep latency. Urinary 6-sulfatoxymelatonin, 5-hydroxyindoleacetic acid levels, and urinary total antioxidant capacity also increased respectively after tryptophan-enriched cereal ingestion as well as improving anxiety and depression symptoms. Cereals enriched with tryptophan may be useful as a chrononutrition tool for alterations in the sleep/wake cycle due to age. PMID:22622709

Bravo, R; Matito, S; Cubero, J; Paredes, S D; Franco, L; Rivero, M; Rodríguez, A B; Barriga, C

2013-08-01

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The impact of elevation data representation on nocturnal drainage wind simulations  

Energy Technology Data Exchange (ETDEWEB)

This document contains information about SABLE, an atmospheric model developed by Lawerence Livermore National Laboratory. The model is a hydrostatic mesoscale model that represents surface-atmosphere interatctions affected by complex terrain. SABLE is used to evaluate the impacts of elevation on drainage systems. The simulation also encompasses wind effects on nocturnal drainage.

Walker, H.; Leone, J.M. Jr.

1994-04-01

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Effects of pressure on the skin exerted by clothing on responses of urinary catecholamines and cortisol, heart rate and nocturnal urinary melatonin in humans  

Science.gov (United States)

The study investigated how the pressure exerted on the skin by clothing worn while working in the daytime affected the urinary excretion of adrenaline, noradrenaline and cortisol, heart rate, and also melatonin secretion at night. Nine young women (experiment I) and seven young women (experiment II) participated. Participants wore either a 100% cotton jacket (tight clothes, TC) or a 100% cotton T-shirt (loose clothes, LC). Loose-fitting, 100% cotton tank tops and panties were worn as underwear in both the TC and the LC groups. The main results can be summarized as follows: (1) urinary excretion of adrenaline, noradrenaline and cortisol was facilitated, and the amounts of urinary excretion were significantly higher when TC were worn. Heart rate was significantly higher in the TC group; (2) nocturnal urinary melatonin excretion was significantly greater in the TC group. These results are discussed in terms of an enhancement of diurnal sympathetic nervous system activity caused by pressure on the skin produced by tight clothing.

Mori, Yuki; Kioka, Etsuko; Tokura, Hiromi

2002-09-01

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Nocturnal plasma levels of melatonin in quails (Coturnix japonica) injected with l-5-hydroxy-tryptophan Níveis plasmáticos noturnos de melatonina em codornas (Coturnix japonica) injetadas com l-5-hidroxi-triptofano  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aimed to demonstrate the influence of the systemic administration of l-5-hydroxy-tryptophan (L-HTP) on the plasma levels of melatonin during the dark period in quails. Throughout daylight, the plasma levels of melatonin did not differ significantly, oscillating between 110.2 ± 15.8 pg.mL-1 and 157.4 ± 34.8 pg.mL-1, from 8 to 16 hours. L-HTP (25 mg.kg-1, through the intracelomic route) administered at 18 hours lessened significantly the nocturnal increase of the plasma...

Lc, Reis; Ac, Almeida; Mc, Ribeiro; Pa, Polo; El, Olivares; Ma, Medeiros; Ko, Nonaka; Lr, Castilhos

2007-01-01

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Nocturnal melatonin concentrations vary dramatically between the two jugular veins in most individual sheep maintained under mimicked or natural photoperiod.  

Science.gov (United States)

Two experiments were designed to determine if melatonin concentrations differ between jugular veins. In a first experiment, blood was collected continuously every 30 min from each jugular during 12-h from 6 ewes. In a second experiment, 100 ewes were sampled twice at night simultaneously from the two jugular veins. In both experiments, mean melatonin concentrations were similar between right and left jugulars. However, within individuals, large differences were observed between the two sides (ppineal gland requires sampling from both jugular veins. PMID:19699498

Zarazaga, L A; Todini, L; Chemineau, P; Marnet, P-G; Locatelli, A; Malpaux, B

2010-04-01

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Occurrence, diel patterns, and the influence of melatonin on the photosynthetic performance of cultured Symbiodinium.  

Science.gov (United States)

Dinoflagellata is the earliest phylum in which true circadian regulation of melatonin rhythms has been convincingly demonstrated. Here, diel profiling of melatonin in a cultured member of this phylum belonging to the genus Symbiodinium indicated that melatonin levels oscillate with significant nocturnal peaks. However, unlike in other previously studied dinoflagellate species, the diel rhythmicity of melatonin in Symbiodinium did not persist under constant dark conditions. Thus, the oscillating pattern of melatonin in Symbiodinium is presumed not to be driven by endogenous circadian control of melatonin production, but rather by changes in the daily photocycle, most likely through a mechanism involving the enhanced photo-consumption of melatonin by free radicals. Although direct interactions of melatonin with detrimental radicals have been previously studied in several basal species, including dinoflagellates, none of these investigations addressed the effects that this molecule may have on photosynthesis, a major source of radical species in unicellular algae. In the present work, real-time monitoring of oxygen evolution in Symbiodinium cultures indicated a significant decrease in photosynthesis rates upon treatment with various doses of melatonin. Analyses of chlorophyll a fluorescence and xanthophyll cycle activity confirmed this effect and further revealed that this slowdown may occur through an enhanced engagement of photoprotective mechanisms in melatonin-treated cells. These findings are of great importance as they demonstrate that in certain photoautotroph species, the interactions of elevated melatonin levels with photosynthesis may extend beyond the general purpose of antioxidant protection. PMID:23496383

Roopin, Modi; Yacobi, Yosef Z; Levy, Oren

2013-08-01

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Seasonal serum concentrations of melatonin in cycling and noncycling mares.  

Science.gov (United States)

To determine whether secretory patterns of melatonin change throughout the seasons in mares, blood samples were drawn byvenipuncture from nine mares at noon and midnight for five successive days at monthly intervals from August through July at the University of Missouri in Columbia, MO. In addition, during September, December, March, and June, blood samples were drawn from indwelling catheters at 2-h intervals for 48 or 72 h. Mares were predominantly Quarter Horses weighing approximately 450 kg and ranged from 3 to 12 yr of age. Mares were housed in outdoor paddocks with three-sided run-in sheds for shelter. During the noon and midnight bleeding period, mares were placed in a larger open-sided barn with outside runs. Mares remained outdoors with the barn being used as a shelter in the event of inclement weather. All lights in the shed were converted to red light. Often, moonlight provided enough illumination to collect blood samples. Mares were returned to their normal paddock after each sampling period. For analysis of data, a mare was considered to be cycling if serum concentrations of progesterone were greater than 1 ng/ mL. For a mare to be classified as exhibiting a nocturnal rise of melatonin, serum concentrations of melatonin had to be at least two times greater at midnight than at noon. By month, a relationship did not exist (chi2; P > 0.05) among mares that were exhibiting estrous cycles and exhibiting nocturnal rises of melatonin. Likewise, examination of serum profiles of melatonin taken at 2-h intervals for 48 h revealed considerable variation among mares throughout the seasons. A nocturnal rise in serum melatonin was observed only in June (P serum melatonin was greater in cycling mares than noncycling mares, but the elevation was not associated with light-dark periods (P serum concentrations of melatonin are used as a cue to regulate cyclic activity in the mare throughout the seasons. PMID:12462263

Diekman, M A; Braun, W; Peter, D; Cook, D

2002-11-01

 
 
 
 
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Morning and nocturnal serum melatonin rhythm levels in patients with major depressive disorder: an analytical cross-sectional study / Medir los niveles del ritmo de melatonina día-noche entre los pacientes con trastorno depresivo mayor: un estudio analítico transversal  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in spanish CONTEXTO Y OBJETIVO: La glándula pineal actúa precisamente regulando los ritmos biológicos de melatonina de hemostasia cerebral, como un órgano adaptativo. La modificación del ritmo de melatonina puede ser el motivo probable del trastorno depresivo. Este estudio se realizó con el objetivo de medir l [...] os niveles de melatonina entre los pacientes con trastorno depresivo mayor y los sanos. DISEÑO Y ESPACIO: Estudio analítico transversal-la unidad medicina laboral de empresa de Zob Ahan de Isfahán-Irán. MÉTODO: Los niveles de melatonina en suero día-noche se midó entre dos grupos (pacientes y sanos) utilizando el método de ELISA (Ensayo por inmunoabsorción ligado a enzimas). Todos los datos se hizo utilizando el análisis de la varianza. RESULTADOS: El nivel de melatonina en suero día-noche era distinto entre los deprimidos y los saludables (P Abstract in english CONTEXT AND OBJECTIVE: The pineal gland is an adaptive organ that precisely regulates the biological rhythms of melatonin brain hemostasis. Variation in the regulation of melatonin rhythms is a likely cause of depressive disorder. The purpose of this study was to measure serum melatonin levels in pa [...] tients with major depressive disorder (MDD) and normal control subjects. DESIGN AND SETTING: Analytical cross-sectional study at the industrial medical unit of the Iron Smelting Company of Isfahan, Iran. METHODS: The morning and nocturnal serum melatonin levels of patients and controls were measured using the enzyme-linked immunosorbent assay (ELISA) method. All data were assessed using variance analysis. RESULTS: The morning and nocturnal serum melatonin levels of depressed and healthy subjects differed (P

Shahnaz, Khaleghipour; Mohsen, Masjedi; Hassan, Ahade; Meersalahodin, Enayate; Gholamreza, Pasha; Farah, Nadery; Gholamhossein, Ahmadzade.

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Effects of intracoronary melatonin on ischemia-reperfusion injury in ST-elevation myocardial infarction  

DEFF Research Database (Denmark)

Acute coronary occlusion is effectively treated by primary percutaneous coronary intervention. However, myocardial ischemia-reperfusion injury is at the moment an unavoidable consequence of the procedure. Oxidative stress is central in the development of ischemia-reperfusion injury. Melatonin, an endogenous hormone, acts through antioxidant mechanisms and could potentially minimize the myocardial injury. The aim of the experimental study was to examine the cardioprotective effects of melatonin in a porcine closed-chest reperfused infarction model. A total of 20 landrace pigs were randomized to a dosage of 200 mg (0.4 mg/mL) melatonin or placebo (saline). The intervention was administered intracoronary and intravenous. Infarct size, area at risk and microvascular obstruction were determined ex vivo by cardiovascular magnetic resonance imaging. Myocardial salvage index was calculated. The plasma levels of high-sensitive troponin T were assessed repeatedly. The experimenters were blinded with regard to treatmentregimen. Melatonin did not significantly increase myocardial salvage index compared with placebo [melatonin 21.8 % (16.1; 24.8) vs. placebo 20.2 % (16.9; 27.0), p = 1.00]. The extent of microvascular obstruction was similar between the groups [melatonin 3.8 % (2.7; 7.1) vs. placebo 3.7 % (1.3; 7.7), p = 0.96]. The area under the curve for high-sensitive troponin T release was insignificantly reduced by 32 % in the melatonin group [AUC melatonin 12,343.9 (6,889.2; 20,147.4) ng h/L vs. AUC placebo 18,285.3 (5,180.4; 23,716.8) ng h/L, p = 0.82]. Combined intracoronary and intravenous treatment with melatonin did not reduce myocardial reperfusion injury. The lack of a positive effect could be due to an ineffective dose of melatonin, a type II error or the timing of administration.

EkelØf, Sarah V; Halladin, Natalie L

2014-01-01

23

Epinephrine preworkout elevation may offset early morning melatonin concentrations to maintain maximal muscular force and power in track athletes.  

Science.gov (United States)

The optimal time of day for training has become an important question for many strength and conditioning specialists, and this study was designed to add some insights into this complex question. The primary purpose of this investigation was to examine physical performance within the temporal context of the relationship between physical performance, epinephrine, and melatonin concentrations in the early morning (0530 hours) and late (1500 hours) afternoon in elite collegiate male track and field athletes (jumpers and sprinters). Subjects had a mean (±SD) age, height, and body mass of 20.4 (±1.6) years, 185.8 (±9.4) cm, and 77.9 (±8.5) kg, respectively. Blood was obtained before each AM and PM testing session. Mean plasma melatonin concentrations were 34.9 ± 22.7 pg·ml and 4.8 ± 3.3 pg·ml for the AM vs. PM trials, respectively, demonstrating a significant (p ? 0.05) difference between time points. Mean resting plasma epinephrine concentrations for AM (171.7 ± 33.7 pmol·L) and PM (127.6 ± 47.8 pmol·L) also differed significantly between trails at the different times. In addition, significant differences were observed with respect to foot quickness in the AM (5.14 ± 1.06 seconds) and PM (4.39 ± 0.76 seconds). Mean peak power output for vertical jump power was 5,407.1 ± 1,272.9 W, 5,384.6 ± 888.3 W for AM vs. PM trials, respectively, which were not significantly different. The results of this investigation indicate that time of day did not negatively impact whole body physical performance in trained track athletes but did impact the quality of quickness. Thus in the morning, whole body power performances may be enhanced through adrenergic arousal when melatonin is elevated. However, this was not the case for movements requiring quickness and accuracy of movement. To compensate for the "sleepiness" associated with high concentrations of melatonin, being secreted from the pineal gland representing a continued "sleepiness" effect on the body, early morning practices may require greater adrenergic arousal to potentially offset melatonin's effects. The results of this study raise important questions on the use of early morning practices for more complex tasks that require high reaction speeds, even under conditions of adrenergic arousal. PMID:24513613

Kraemer, William J; Boyd, Brittny M; Hooper, David R; Fragala, Maren S; Hatfield, Disa L; Dunn-Lewis, Courtenay; Comstock, Brett A; Szivak, Tunde K; Flanagan, Shawn D; Looney, David P; Newton, Robert U; Vingren, Jakob L; Häkkinen, Keijo; White, Mark T; Volek, Jeff S; Maresh, Carl M

2014-09-01

24

Average diurnal changes in melatonin levels are associated with hourly incidence of bereavement apparitions: support for the hypothesis of temporal (limbic) lobe microseizuring.  

Science.gov (United States)

Transient suppressions of nocturnal melatonin levels due to enhanced geomagnetic activity have been suggested as the precipitating source of experiences of postmortem (bereavement) apparitions when the brain has been sensitized (grief) by elevations of the epileptogenic neuropeptide, corticotrophin-releasing factor. Although the hourly incidence of subjective experiences of telepathy, precognition, and bereavement apparitions were all significantly correlated with published indices of hourly melatonin levels, only the significant association between melatonin levels and apparitions was not changed when the other two classes of psi experiences were held constant. PMID:8387181

Persinger, M A

1993-04-01

25

Nocturnal plasma levels of melatonin in quails (Coturnix japonica) injected with l-5-hydroxy-tryptophan / Níveis plasmáticos noturnos de melatonina em codornas (Coturnix japonica) injetadas com l-5-hidroxi-triptofano  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho objetivou demonstrar a influência da administração sistêmica de l-5-hidroxi-triptofano (L-HTP) sobre os níveis plasmáticos de melatonina durante o período noturno em codornas. Ao longo do período claro, os níveis plasmáticos de melatonina não diferiram significativamente, oscilando ent [...] re 110,2 ± 15,8 pg.mL-1 e 157,4 ± 34,8 pg.mL-1, de 8 às 16 horas. L-HTP (25 mg.kg-1, via intracelomática), administrado às 18 horas atenuou significativamente a elevação noturna dos níveis plasmáticos de melatonina (controles, 327,3 ± 20,1 e 315,8 ± 20,9 pg.mL-1 vs. 242,1 ± 24,8 e 217,5 ± 21 pg.mL-1, respectivamente, às 20 e 24 horas, P Abstract in english This study aimed to demonstrate the influence of the systemic administration of l-5-hydroxy-tryptophan (L-HTP) on the plasma levels of melatonin during the dark period in quails. Throughout daylight, the plasma levels of melatonin did not differ significantly, oscillating between 110.2 ± 15.8 pg.mL- [...] 1 and 157.4 ± 34.8 pg.mL-1, from 8 to 16 hours. L-HTP (25 mg.kg-1, through the intracelomic route) administered at 18 hours lessened significantly the nocturnal increase of the plasma levels of melatonin (controls, 327.3 ± 20.1 and 315.8 ± 20.9 pg.mL-1 vs. 242.1 ± 24.8 and 217.5 ± 21 pg.mL-1, respectively, at 20 and 24 hours, P

LC., Reis; AC., Almeida; MC., Ribeiro; PA., Polo; EL., Olivares; MA., Medeiros; KO., Nonaka; LR., Castilhos.

2007-05-01

26

Nocturnal plasma levels of melatonin in quails (Coturnix japonica) injected with l-5-hydroxy-tryptophan / Níveis plasmáticos noturnos de melatonina em codornas (Coturnix japonica) injetadas com l-5-hidroxi-triptofano  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho objetivou demonstrar a influência da administração sistêmica de l-5-hidroxi-triptofano (L-HTP) sobre os níveis plasmáticos de melatonina durante o período noturno em codornas. Ao longo do período claro, os níveis plasmáticos de melatonina não diferiram significativamente, oscilando ent [...] re 110,2 ± 15,8 pg.mL-1 e 157,4 ± 34,8 pg.mL-1, de 8 às 16 horas. L-HTP (25 mg.kg-1, via intracelomática), administrado às 18 horas atenuou significativamente a elevação noturna dos níveis plasmáticos de melatonina (controles, 327,3 ± 20,1 e 315,8 ± 20,9 pg.mL-1 vs. 242,1 ± 24,8 e 217,5 ± 21 pg.mL-1, respectivamente, às 20 e 24 horas, P Abstract in english This study aimed to demonstrate the influence of the systemic administration of l-5-hydroxy-tryptophan (L-HTP) on the plasma levels of melatonin during the dark period in quails. Throughout daylight, the plasma levels of melatonin did not differ significantly, oscillating between 110.2 ± 15.8 pg.mL- [...] 1 and 157.4 ± 34.8 pg.mL-1, from 8 to 16 hours. L-HTP (25 mg.kg-1, through the intracelomic route) administered at 18 hours lessened significantly the nocturnal increase of the plasma levels of melatonin (controls, 327.3 ± 20.1 and 315.8 ± 20.9 pg.mL-1 vs. 242.1 ± 24.8 and 217.5 ± 21 pg.mL-1, respectively, at 20 and 24 hours, P

LC., Reis; AC., Almeida; MC., Ribeiro; PA., Polo; EL., Olivares; MA., Medeiros; KO., Nonaka; LR., Castilhos.

27

Melatonin receptors in pancreatic islets: good morning to a novel type 2 diabetes gene.  

Science.gov (United States)

Melatonin is a circulating hormone that is primarily released from the pineal gland. It is best known as a regulator of seasonal and circadian rhythms; its levels are high during the night and low during the day. Interestingly, insulin levels also exhibit a nocturnal drop, which has previously been suggested to be controlled, at least in part, by melatonin. This regulation can be explained by the proposed inhibitory action of melatonin on insulin release. Indeed, both melatonin receptor 1A (MTNR1A) and MTNR1B are expressed in pancreatic islets. The role of melatonin in the regulation of glucose homeostasis has been highlighted by three independent publications based on genome-wide association studies of traits connected with type 2 diabetes, such as elevated fasting glucose, and, subsequently, of the disease itself. The studies demonstrate a link between variations in the MTNR1B gene, hyperglycaemia, impaired early phase insulin secretion and beta cell function. The risk genotype predicts the future development of type 2 diabetes. Carriers of the risk genotype exhibit increased expression of MTNR1B in islets. This suggests that these individuals may be more sensitive to the actions of melatonin, leading to impaired insulin secretion. Blocking the inhibition of insulin secretion by melatonin may be a novel therapeutic avenue for type 2 diabetes. PMID:19377888

Mulder, H; Nagorny, C L F; Lyssenko, V; Groop, L

2009-07-01

28

Melatonin and metabolic regulation: a review.  

Science.gov (United States)

Human life expectancy has increased over the past 50 years due to scientific and medical advances and higher food availability. However, overweight and obesity affect more than 50% of adults and 15% of infants and adolescents. There has also been a marked increase in the prevalence of metabolic syndrome in recent decades, which has been associated with a reduction in nocturnal pineal production of melatonin with aging and an increased risk of coronary diseases, type 2 diabetes mellitus (T2DM) and death. Melatonin is currently under intensive investigation in experimental animal models of diabetes, obesity and MS at pharmacological doses (between 5 and 20 mg kg(-1) body weight), demonstrating its capacity to ameliorate the total metabolic profile and its potential as an alternative to conventional drug therapies for the disorders associated with the MS, i.e. elevated systolic blood pressure, and impairment of glucose homeostasis, plasma lipid profile, inflammation, oxidative stress, and increased body weight. An especially significant finding is the induction by melatonin of white adipose tissue browning, which may be related to its effects against oxidative stress, uncoupling the mitochondrial bioenergetic process by enhancing the expression of uncoupled-protein-1 (UCP-1), which has been related to body weight reduction in experimental animals. Further research is required to improve knowledge of this mechanism. Clinical studies are needed with the administration of pharmacological melatonin doses, because the dose has ranged between 0.050 and 0.16 mg kg(-1) bw in most studies to date. Melatonin is a natural phytochemical, and it is also important to test its beneficial metabolic effects when consumed in functional foods. PMID:25207999

Navarro-Alarcón, Miguel; Ruiz-Ojeda, Francisco J; Blanca-Herrera, Rosa M; A-Serrano, María Mohammad; Acuña-Castroviejo, Dario; Fernández-Vázquez, Gumersindo; Agil, Ahmad

2014-10-22

29

Delivery of pineal melatonin to the brain and SCN: role of canaliculi, cerebrospinal fluid, tanycytes and Virchow-Robin perivascular spaces.  

Science.gov (United States)

Historically, the direct release of pineal melatonin into the capillary bed within the gland has been accepted as the primary route of secretion. Herein, we propose that the major route of melatonin delivery to the brain is after its direct release into the cerebrospinal fluid (CSF) of the third ventricle (3V). Melatonin concentrations in the CSF are not only much higher than in the blood, also, there is a rapid nocturnal rise at darkness onset and precipitous decline of melatonin levels at the time of lights on. Because melatonin is a potent free radical scavenger and antioxidant, we surmise that the elevated CSF levels are necessary to combat the massive free radical damage that the brain would normally endure because of its high utilization of oxygen, the parent molecule of many toxic oxygen metabolites, i.e., free radicals. Additionally, the precise rhythm of CSF melatonin provides the master circadian clock, the suprachiasmatic nucleus, with highly accurate chronobiotic information regarding the duration of the dark period. We predict that the discharge of melatonin directly into the 3V is aided by a number of epithalamic structures that have heretofore been overlooked; these include interpinealocyte canaliculi and evaginations of the posterodorsal 3V that directly abut the pineal. Moreover, the presence of tanycytes in the pineal recess and/or a discontinuous ependymal lining in the pineal recess allows melatonin ready access to the CSF. From the ventricles melatonin enters the brain by diffusion and by transport through tanycytes. Melatonin-rich CSF also circulates through the aqueduct and eventually into the subarachnoid space. From the subarachnoid space surrounding the brain, melatonin penetrates into the deepest portions of the neural tissue via the Virchow-Robin perivascular spaces from where it diffuses into the neural parenchyma. Because of the high level of pineal-derived melatonin in the CSF, all portions of the brain are better shielded from oxidative stress resulting from toxic oxygen derivatives. PMID:24553808

Reiter, Russel J; Tan, Dun Xian; Kim, Seok Joong; Cruz, Maria Helena C

2014-11-01

30

Nocturnal plasma levels of melatonin in quails (Coturnix japonica injected with l-5-hydroxy-tryptophan Níveis plasmáticos noturnos de melatonina em codornas (Coturnix japonica injetadas com l-5-hidroxi-triptofano  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to demonstrate the influence of the systemic administration of l-5-hydroxy-tryptophan (L-HTP on the plasma levels of melatonin during the dark period in quails. Throughout daylight, the plasma levels of melatonin did not differ significantly, oscillating between 110.2 ± 15.8 pg.mL-1 and 157.4 ± 34.8 pg.mL-1, from 8 to 16 hours. L-HTP (25 mg.kg-1, through the intracelomic route administered at 18 hours lessened significantly the nocturnal increase of the plasma levels of melatonin (controls, 327.3 ± 20.1 and 315.8 ± 20.9 pg.mL-1 vs. 242.1 ± 24.8 and 217.5 ± 21 pg.mL-1, respectively, at 20 and 24 hours, P Este trabalho objetivou demonstrar a influência da administração sistêmica de l-5-hidroxi-triptofano (L-HTP sobre os níveis plasmáticos de melatonina durante o período noturno em codornas. Ao longo do período claro, os níveis plasmáticos de melatonina não diferiram significativamente, oscilando entre 110,2 ± 15,8 pg.mL-1 e 157,4 ± 34,8 pg.mL-1, de 8 às 16 horas. L-HTP (25 mg.kg-1, via intracelomática, administrado às 18 horas atenuou significativamente a elevação noturna dos níveis plasmáticos de melatonina (controles, 327,3 ± 20,1 e 315,8 ± 20,9 pg.mL-1 vs. 242,1 ± 24,8 e 217,5 ± 21 pg.mL-1, respectivamente, às 20 e 24 horas, P < 0,05. Os resultados obtidos mostraram que a administração de L-HTP reduziu a liberação noturna de melatonina, possivelmente por suscitar um aumento da síntese e liberação sináptica de serotonina na pineal. Portanto, a transmissão serotoninérgica da rafe para a pineal constituiria um mecanismo de modulação da síntese e/ou liberação de melatonina em codornas.

LC. Reis

2007-05-01

31

Experimental models of melatonin-deficient hypertension.  

Science.gov (United States)

Melatonin secreted by the pineal gland plays an important role in the regulation of blood pressure (BP) and its administration reduces hypertension both in animals and humans. There are two experimental models of melatonin-deficient hypertension: one induced by pinealectomy and another by continuous 24 hour exposure to light. Both models cause melatonin deficiency and prevent darkness-mediated nocturnal melatonin secretion and are associated with increased BP and myocardial, vascular and renal dysfunction. These models also lead to neurohumoral activation of the renin-angiotensin system, sympathetic nervous system, adrenocorticotrophin-glucocorticoid axis and cause insulin resistance. Together, these alterations contribute to rise in blood pressure by vasoconstrictive or circulatory fluid volume overload. The light induced hypertension model mimics the melatonin deficiency in patients with insufficient nocturnal BP decline, in those who have night shift or who are exposed to environmental light pollution. For this reason, this model is useful in development of anti-hypertensive drugs. PMID:23276947

Simko, Fedor; Reiter, Russel J; Pechanova, Olga; Paulis, Ludovit

2013-01-01

32

Melatonin as a proconvulsive hormone in humans.  

Science.gov (United States)

The pineal gland and melatonin exert a major influence in the control of brain electrical activity and have been shown to be involved in seizure and sleep mechanisms. Since pinealectomy has been reported to result in seizures in experimental animals, it is assumed that melatonin has anticonvulsant properties. Indeed, limited studies in humans with temporal lobe epilepsy indicate that melatonin attenuates seizure activity. In the present communication we present evidence, based on magnetoencephalographic (MEG) brain measurements, that melatonin may exert proconvulsive activity in humans as well. The proconvulsive properties of melatonin may explain several phenomena associated with epilepsy such as the increased occurrence of seizures at night when melatonin plasma levels are 5 to 8-fold higher than during the day and the observed exacerbation of seizures premenstrually and during pregnancy as well as the attenuation of seizures in the menopause. Furthermore, our findings suggest that anticonvulsants which decrease melatonin secretion, such as the benzodiazepines, may exert their antiepileptic activity by attenuating nocturnal melatonin secretion. Finally, we propose that patients with nocturnal epilepsy or those experiencing exacerbation of seizures premenstrually may benefit from the administration of agents which block the secretion or action of melatonin. PMID:1342024

Sandyk, R; Tsagas, N; Anninos, P A

1992-03-01

33

Nocturnal Asthma  

Science.gov (United States)

... Medical Director, Health Initiatives View full profile Nocturnal Asthma Worsening of asthma at night, or nocturnal asthma, ... Calendar Read the News View Daily Pollen Count Asthma Treatment Program At National Jewish Health, we offer ...

34

Melatonin concentrations in the two jugular veins, and relationship with the seasonal reproductive activity in goats  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The authors investigated whether melatonin concentrations vary between the two jugular veins and whether absolute (nocturnal) or relative (nocturnal/diurnal ratio) plasma melatonin concentrations are associated with seasonal reproductive activity measured by oestrus or ovulatory activity in Payoya goats. Thirty-two adult Payoya goats were penned under natural photoperiod. Oestrus activity was tested daily using aproned males-twice a week plasma was sampled for progesterone. Melatonin plasma c...

Zarazaga Garce?s, Luis A?ngel; Celi Maria?tegui, Irma Del Rosario; Guzma?n Guerrero, Jose? Luis; Malpaux, B.

2010-01-01

35

Non-vertebrate melatonin.  

Science.gov (United States)

Melatonin has been detected in bacteria, eukaryotic unicells, macroalgae, plants, fungi and various taxa of invertebrates. Although precise determinations are missing in many of these organisms and the roles of melatonin are still unknown, investigations in some species allow more detailed conclusions. Non-vertebrate melatonin is not necessarily circadian, and if so, not always peaking at night, although nocturnal maxima are frequently found. In the cases under study, the major biosynthetic pathway is identical with that of vertebrates. Mimicking of photoperiodic responses and concentration changes upon temperature decreases have been studied in more detail only in dinoflagellates. In plants, an involvement in photoperiodism seems conceivable but requires further support. No stimulation of flowering has been demonstrated to date. A participation in antioxidative protection might be possible in many aerobic non-vertebrates, although evidence for a contribution at physiological levels is mostly missing. Protection from stress by oxidotoxins or/and extensions of lifespan have been shown in very different organisms, such as the dinoflagellate Lingulodinium, the ciliate Paramecium, the rotifer Philodina and Drosophila. Melatonin can be taken up from the food, findings with possible implications in ecophysiology as well as for human nutrition and, with regard to high levels in medicinal plants, also in pharmacology. PMID:12662344

Hardeland, Rüdiger; Poeggeler, Burkhard

2003-05-01

36

Dietary factors and fluctuating levels of melatonin  

Directory of Open Access Journals (Sweden)

Full Text Available Melatonin is secreted principally by the pineal gland and mainly at nighttime. The primary physiological function is to convey information of the daily cycle of light and darkness to the body. In addition, it may have other health-related functions. Melatonin is synthesized from tryptophan, an essential dietary amino acid. It has been demonstrated that some nutritional factors, such as intake of vegetables, caffeine, and some vitamins and minerals, could modify melatonin production but with less intensity than light, the most dominant synchronizer of melatonin production. This review will focus on the nutritional factors apart from the intake of tryptophan that affect melatonin levels in humans. Overall, foods containing melatonin or promoting the synthesis of it by impacting the availability of tryptophan, as well those containing vitamins and minerals which are needed as co-factors and activators in the synthesis of melatonin, may modulate the levels of melatonin. Even so, the influence of daytime diet on the synthesis of nocturnal melatonin is limited, however, the influence of the diet seems to be more obvious on the daytime levels.

Katri Peuhkuri

2012-07-01

37

Dietary factors and fluctuating levels of melatonin.  

Science.gov (United States)

Melatonin is secreted principally by the pineal gland and mainly at nighttime. The primary physiological function is to convey information of the daily cycle of light and darkness to the body. In addition, it may have other health-related functions. Melatonin is synthesized from tryptophan, an essential dietary amino acid. It has been demonstrated that some nutritional factors, such as intake of vegetables, caffeine, and some vitamins and minerals, could modify melatonin production but with less intensity than light, the most dominant synchronizer of melatonin production. This review will focus on the nutritional factors apart from the intake of tryptophan that affect melatonin levels in humans. Overall, foods containing melatonin or promoting the synthesis of it by impacting the availability of tryptophan, as well those containing vitamins and minerals which are needed as co-factors and activators in the synthesis of melatonin, may modulate the levels of melatonin. Even so, the influence of daytime diet on the synthesis of nocturnal melatonin is limited, however, the influence of the diet seems to be more obvious on the daytime levels. PMID:22826693

Peuhkuri, Katri; Sihvola, Nora; Korpela, Riitta

2012-01-01

38

Seasonal Patterns of Melatonin, Cortisol, and Progesterone Secretion in Female Lambs Raised Beneath a 500-kV Transmission Line.  

Energy Technology Data Exchange (ETDEWEB)

Although several kinds of biological effects of electric and magnetic fields have been reported from laboratory studies, few have been independently replicated. When this study was being planned, the suppression of nighttime melatonin in rodents was thought to represent one of the strongest known effects of these fields. The effect had been replicated by a single laboratory for 60-Hz electric fields, and by multiple laboratories for d-c magnetic fields. The primary objective of this study was to determine whether the effect of electric and magnetic fields on melatonin would also occur in sheep exposed to a high voltage transmission line. The specific hypothesis tested by this experiment was as follows: The electrical environment produced by a 60-Hz, 500-kV transmission line causes a depression in nocturnal melatonin in chronically exposed female lambs. This may mimic effects of pinealectomy or constant long-day photoperiods, thus delaying the onset of reproductive cycles. Results of the study do not provide evidence to support the hypothesis. Melatonin concentrations in the sheep exposed to the transmission line showed the normal pattern of low daytime and high nighttime serum levels. As compared to the control group, there were no statistically significant group differences in the mean amplitude, phase, or duration of the nighttime melatonin elevation.

Lee, Jack M.

1992-06-01

39

Melatonin and LH secretion patterns in pubertal boys  

International Nuclear Information System (INIS)

Plasma melatonin and LH were measured at 20 minute intervals for 24 hours in four normal pubertal boys. All four subjects showed a significant augmentation of LH and melatonin during nocturnal sleep. There was also a significant correlation between the LH and melatonin levels (p<0.001). There were periods of episodic secretion of melanin during the diurnal waking period which seemed related to 'stress'. These data indicate that the peripheral concentrations of melatonin which occur during sleep are insufficient to prevent spontaneous LH secretion during puberty

40

Melatonin production in the sea star Echinaster brasiliensis (Echinodermata).  

Science.gov (United States)

The primary hormone of the vertebrate pineal gland, melatonin, has been identified broadly throughout the tree of life, in animals, plants, and fungi, supporting a deep evolutionary origin for this signaling molecule. However, some key groups have not been studied. Echinoderms, deuterostome animals, are one of these groups. Herein we study the presence of melatonin and enzymes of its pathway in the sea star Echinaster brasiliensis. We demonstrate that E. brasiliensis produces endogenous melatonin, in the gonads, under a circadian pattern with a nocturnal peak of production. We also show that the enzymes arylalkylamine N-acetyltransferase (AANAT) and tryptophan hydroxylase (TPH) are present and are probably regulating the melatonin production. PMID:24797096

Peres, Rafael; Amaral, Fernanda Gaspardo; Marques, Antonio Carlos; Neto, José Cipolla

2014-04-01

 
 
 
 
41

MELATONIN: POTENTIAL UTILITY FOR IMPROVING PUBLIC HEALTH  

Directory of Open Access Journals (Sweden)

Full Text Available This review summarizes the beneficial actions of melatonin in various experimental conditions/diseases and identifies where the use of melatonin may be helpful in improving public health. The nightly use of melatonin supplements by humans often improves their sleep and helps correct the circadian dyssynchronization associated with “jet lag”. Additionally, melatonin has been found effective in curtailing the growth of a variety of experimental cancers. Mechanistically, this is achieved by melatonin’s ability to limit fatty acid uptake, especially linoleic acid, by tumor cells. Fatty acids are growth factors for many tumors. Additionally, melatonin inhibits the elevated telomerase activity of tumor cells thus making them more fragile and vulnerable to chemotherapies. Melatonin also may inhibit angiogenesis in tumors by suppressing endothelin-1 production and the indole interferes with the stimulatory action of steroids on hormone-responsive tumors. As an ubiquitously-acting antioxidant, melatonin reduces cardiac damage during ischemia/reperfusion (I/R injury (heart attack and during I/R to the brain (stroke. Melatonin also limits the toxicity of amyloid ? peptide and of neurofibrillary tangles, two of the cardinal signs of Alzheimer’s disease. Collectively, these data suggest supplementation with melatonin, whose endogenous levels decrease with age, may improve the quality of life in the aged and, as a consequence, be beneficial for public health generally. [TAF Prev Med Bull 2006; 5(2.000: 131-158

Russel J REITER; Fatih GULTEKIN; Luis J FLORES; Ma Pilar TERRON; Dun-Xian TAN

2006-04-01

42

Melatonin signaling controls circadian swimming behavior in marine zooplankton.  

Science.gov (United States)

Melatonin, the "hormone of darkness," is a key regulator of vertebrate circadian physiology and behavior. Despite its ubiquitous presence in Metazoa, the function of melatonin signaling outside vertebrates is poorly understood. Here, we investigate the effect of melatonin signaling on circadian swimming behavior in a zooplankton model, the marine annelid Platynereis dumerilii. We find that melatonin is produced in brain photoreceptors with a vertebrate-type opsin-based phototransduction cascade and a light-entrained clock. Melatonin released at night induces rhythmic burst firing of cholinergic neurons that innervate locomotor-ciliated cells. This establishes a nocturnal behavioral state by modulating the length and the frequency of ciliary arrests. Based on our findings, we propose that melatonin signaling plays a role in the circadian control of ciliary swimming to adjust the vertical position of zooplankton in response to ambient light. PMID:25259919

Tosches, Maria Antonietta; Bucher, Daniel; Vopalensky, Pavel; Arendt, Detlev

2014-09-25

43

Nocturnal Animals  

Science.gov (United States)

Over time, human beings have blazed their way into the night with fire and artificial light, but we are not true creatures of the night. This Topic in Depth explores the world of nocturnal animals. From Island Discovery & Training, the first site allows visitors to listen to the sounds of several nocturnal animals. After guessing who made the sound, visitors can link to information pages for all but one of the mystery animals (1). Next is an information sheet (2) from BioMedia that answers the question: How Do Animals See In the Dark? The third site, from Enchanted Learning, provides coloring sheets and brief profiles for many nocturnal animals including the Amur Tiger, Badger, Crocodile, and Kinkajou-just to name a few (3). From the Fairbanks Museum & Planetarium in Vermont, the fourth website contains a six-page lesson plan (for students in grades one to eight) emphasizing different senses; and the roles and adaptations of nocturnal species (4). The fifth site, from Science News Online, contains an article addressing research on the ecological impact of artificial nighttime light on nocturnal animals (5). From Wild Asia, the next site contains an article by travel writer and environmental educator David Bowden, that describes his experience watching a marine turtle lay her eggs on Malaysia's Turtle Island (6). The seventh site, from PBS-Nova Online, briefly describes the work of zoologists who study nocturnal and burrowing animals of the Kalahari (7). From this site visitors can also link to a section that discusses how several different animals see at night. The final site, from the University of Utah-John Moran Eye Center, contains information about the role of photoreceptors in vision (8). This Photoreceptors section is part of a comprehensive electronic tutorial regarding neural organization of the mammalian retina.

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Circadian stage-dependent inhibition of human breast cancer metabolism and growth by the nocturnal melatonin signal: consequences of its disruption by light at night in rats and women.  

Science.gov (United States)

The circadian production of melatonin by the pineal gland during the night provides an inhibitory signal to tissue-isolated steroid receptor SR+ and - MCF-7 human breast cancer xenografts in female nude rats. A pivotal mechanism for melatonin's anticancer effects in vivo involves a melatonin receptor-mediated inhibition of linoleic acid (LA) uptake and its metabolism to mitogenically active 13-hydroxyoctadecadienoic acid (13-HODE). Exposure of (SR-) xenograft-bearing rats to increasing intensities of polychromatic white light at night suppresses melatonin while increasing tumor growth rates, DNA content, [3H]thymidine incorporation into DNA, LA uptake, 13-HODE formation, cAMP levels and ERK1/2 activation a dose-dependent manner. Similar effects occur in SR- human breast cancer xenografts perfused in situ with melatonin-depleted blood from healthy female subjects after their exposure to a single bright intensity (2800 lux) of polychromatic light at night. Additionally, SR- human breast cancer xenografts exhibit robust circadian rhythms of LA uptake, 13-HODE formation and proliferative activity. Exposure of xenograft-bearing rats to dim light at night results in the complete elimination of these rhythms which culminates in unfettered, high rates of tumor metabolism and growth. The organization of tumor metabolism and growth within circadian time structure by the oncostatic melatonin signal helps create a balance between the cancer and its host that is disrupted by host exposure to light at night. This biological mechanism may partially explain the higher risk of breast and other cancers in women working rotating night shifts and possibly others who also experience prolonged exposure to light at night. PMID:20042410

Blask, David E; Dauchy, Robert T; Brainard, George C; Hanifin, John P

2009-12-01

45

Intake of melatonin increases tryptophan hydroxylase type 1 activity in aged rats: Preliminary study.  

Science.gov (United States)

Pineal melatonin is important not only for synchronization of biological rhythms, but also in the ageing process as a potential drug to relieve oxidative damage. During ageing, the nocturnal melatonin production decreases resulting in an increased incidence of disorders. Present in vivo experiments were performed to study the effects of exogenous melatonin chronically administered to old rats on the pineal biosynthesis of melatonin and the precursor serotonin (5-HT) mediated by tryptophan hydroxylase type 1 (TPH-1). Accumulation of 5-hydroxytryptophan (5-HTP) after decarboxylase inhibition was used as a measure of the TPH-1 activity. 5-HT and its metabolite 5-HIAA were also quantified by HPLC-ED. As expected, ageing resulted in worsening of different neurochemical parameters. However, chronic intake of melatonin (1mg/kg/day, diluted in drinking water, 4 weeks) increased TPH-1 activity and significantly improved the age-induced deficits in nocturnal melatonin content in the pineal gland. Results suggest that melatonin intake (or melatonin rich foods) may contribute to recover the pineal function preventing the nocturnal descent of 5-HT and melatonin biosynthesis that normally occur in pineal gland as a consequence of ageing. PMID:24189046

Moranta, D; Barceló, P; Aparicio, S; Garau, C; Sarubbo, F; Ramis, M; Nicolau, C; Esteban, S

2014-01-01

46

Photic and circadian regulation of retinal melatonin in mammals  

Science.gov (United States)

Several studies have established that melatonin synthesis occurs in the retina of vertebrates, including mammals. In mammals, a subpopulation of photoreceptors (probably the cones) synthesize melatonin. Melatonin synthesis in the retina is elevated at night and reduced during the day in a fashion similar to events in the pineal gland. Both the MT1 and MT2 melatonin receptors are present in the retina and retinal melatonin does not contribute to circulating levels, suggesting that retinal melatonin acts locally as a neurohormone and/or neuromodulator. Melatonin synthesis in the retina of mammals is under the control of a circadian oscillator, and circadian rhythms in melatonin synthesis and/or release have been described for several species of mammals. These rhythms are present in vivo, persist in vitro, are entrained by light and are temperature compensated. The cloning of the gene responsible for the synthesis of the enzyme arylalkylamine N-acetyltransferase (the key enzyme in the melatonin biosynthetic pathway) has allowed studies of the molecular mechanisms responsible for the generation of retinal melatonin rhythmicity. The present review focuses on the cellular and molecular mechanisms that regulate melatonin synthesis. In particular, we discuss how the photic environment and the circadian clock interact in determining melatonin levels, in addition to the role that melatonin plays in retinal physiology.

Tosini, G.; Fukuhara, C.

2003-01-01

47

Melatonin: an internal signal for daily and seasonal timing.  

Science.gov (United States)

Melatonin is secreted only during night, irrespective of the habitat of an organism and the site of its synthesis and secretion, and hence known as "darkness hormone". Elevated melatonin levels reflect the nighttime. In vertebrates, the main site of melatonin production is the pineal gland. Species in which melatonin is also secreted from sources other than the pineal, as in some birds, relative contributions of different melatonin producing tissues to the blood melatonin level can vary from species to species. Melatonin acts through its receptors, which are members of the G protein-coupled (GPCR) superfamily. Three melatonin receptors subtypes MT1 (mella), MT2 (mellb), and MT3 (mellc) have been identified in different brain areas and other body organs of vertebrates. Melatonin synthesis and secretion are circadianly rhythmic. Changes and differences in specific features of melatonin signal can vary among species, and under a variety of natural environmental conditions. Two major physiological roles of melatonin are established in vertebrates. First, melatonin is involved in the circadian system regulated behavioural and physiological functions. Second, it is critical for the photoperiodic system. Besides, melatonin has been implicated in various ways both directly and indirectly to human health, including jet lag, sleep, immune system and cancer. PMID:24851405

Trivedi, Amit Kumar; Kumar, Vinod

2014-05-01

48

Nocturnal enuresis  

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Full Text Available Nocturnal enuresis is one of the most common urinary problems in children and is observed in about 15-20 percent of children 5 years of age. Nocturnal enuresis resolves at a rate of 15% per year, so 99% of children are dry by the age of fifteen years. Enuresis can be defined as repetative bed wetting while sleeping. Enuresis in children without any other lower urinary tract (LUT symptoms -excluding nocturia- and without a history of bladder dysfunction is defined as monosymptomatic enuresis. Most of the enuretic children belong to this group. A bladder dysfunction must be kept in mind in an enuretic child having day time symptoms. Behavioral treatment approaches, alarm treatment and pharmacological treatment are the most frequently used approaches for treatment. In all treatment modalities and especially in alarm treatment, the motivation and active involvement of the family and the child are very important. (Turk Arch Ped 2012; 47: 78-83

R. Yavuz Akman

2012-06-01

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Advances in the research of melatonin in autism spectrum disorders: literature review and new perspectives.  

Science.gov (United States)

Abnormalities in melatonin physiology may be involved or closely linked to the pathophysiology and behavioral expression of autistic disorder, given its role in neurodevelopment and reports of sleep-wake rhythm disturbances, decreased nocturnal melatonin production, and beneficial therapeutic effects of melatonin in individuals with autism. In addition, melatonin, as a pineal gland hormone produced from serotonin, is of special interest in autistic disorder given reported alterations in central and peripheral serotonin neurobiology. More specifically, the role of melatonin in the ontogenetic establishment of circadian rhythms and the synchronization of peripheral oscillators opens interesting perspectives to ascertain better the mechanisms underlying the significant relationship found between lower nocturnal melatonin excretion and increased severity of autistic social communication impairments, especially for verbal communication and social imitative play. In this article, first we review the studies on melatonin levels and the treatment studies of melatonin in autistic disorder. Then, we discuss the relationships between melatonin and autistic behavioral impairments with regard to social communication (verbal and non-verbal communication, social interaction), and repetitive behaviors or interests with difficulties adapting to change. In conclusion, we emphasize that randomized clinical trials in autism spectrum disorders are warranted to establish potential therapeutic efficacy of melatonin for social communication impairments and stereotyped behaviors or interests. PMID:24129182

Tordjman, Sylvie; Najjar, Imen; Bellissant, Eric; Anderson, George M; Barburoth, Marianne; Cohen, David; Jaafari, Nemat; Schischmanoff, Olivier; Fagard, Rémi; Lagdas, Enas; Kermarrec, Solenn; Ribardiere, Sophie; Botbol, Michel; Fougerou, Claire; Bronsard, Guillaume; Vernay-Leconte, Julie

2013-01-01

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Increased delta aminolevulinic acid and decreased pineal melatonin production. A common event in acute porphyria studies in the rat.  

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Tryptophan (TRP) is the precursor of melatonin, the primary secretory product of the pineal gland. Hepatic heme deficiency decreases the activity of liver tryptophan pyrrolase, leading to increased plasma TRP and serotonin. As a paradox, patients with attacks of acute intermittent porphyria (AIP), exhibit low nocturnal plasma melatonin levels. This study using a rat experimental model was designed to produce a pattern of TRP and melatonin production similar to that in AIP patients. Pineal mel...

Puy, H.; Deybach, J. C.; Bogdan, A.; Callebert, J.; Baumgartner, M.; Voisin, P.; Nordmann, Y.; Touitou, Y.

1996-01-01

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Ethanol consumption and pineal melatonin daily profile in rats.  

Science.gov (United States)

It is well known that melatonin participates in the regulation of many important physiological functions such as sleep-wakefulness cycle, motor coordination and neural plasticity, and cognition. However, as there are contradictory results regarding the melatonin production diurnal profile under alcohol consumption, the aim of this paper was to study the phenomenology and mechanisms of the putative modifications on the daily profile of melatonin production in rats submitted to chronic alcohol intake. The present results show that rats receiving 10% ethanol in drinking water for 35 days display an altered daily profile of melatonin production, with a phase delay and a reduction in the nocturnal peak. This can be partially explained by a loss of the daily rhythm and the 25% reduction in tryptophan hydroxylase activity and, mainly, by a phase delay in arylalkylamine N-acetyltransferase gene expression and a 70% reduction in its peak activity. Upstream in the melatonin synthesis pathway, the results showed that noradrenergic signaling is impaired as well, with a decrease in ?1 and ?1 adrenergic receptors' mRNA contents and in vitro sustained loss of noradrenergic-stimulated melatonin production by glands from alcohol-treated rats. Together, these results confirm the alterations in the daily melatonin profile of alcoholic rats and suggest the possible mechanisms for the observed melatonin synthesis modification. PMID:21635669

Peres, Rafael; do Amaral, Fernanda Gaspar; Madrigrano, Thiago Cardoso; Scialfa, Julieta Helena; Bordin, Silvana; Afeche, Solange Castro; Cipolla-Neto, José

2011-10-01

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Diets enriched with a Jerte Valley cherry-based nutraceutical product reinforce nocturnal behaviour in young and old animals of nocturnal (Rattus norvegicus) and diurnal (Streptopelia risoria) chronotypes.  

Science.gov (United States)

The decline in melatonin secretion with age seems to be one of the major reasons for increased sleep disruption in older animals. Previously, we showed that the administration with melatonin or its precursor, tryptophan, improved activity/rest rhythms in aged individuals. Here, it was evaluated the effect of a 10-day consumption of a Jerte Valley cherry-based nutraceutical product (patent no. ES2342141B1), which contains high levels of tryptophan, serotonin and melatonin, on the activity/rest rhythms of young and old rats (Rattus norvegicus) and ringdoves (Streptopelia risoria) as representatives of animals with nocturnal and diurnal habits, respectively, and its possible relationship with the serum levels of melatonin and glucose. Total diurnal and nocturnal activity pulses were logged at control, during, and up to 3?days after the treatment. Melatonin and glucose were measured with ELISA and testing kits respectively. In both young and old rats, the intake of the cherry nutraceutical decreased diurnal activity, whereas nocturnal activity increased. The opposite effect was observed for ringdoves. The treatment increased the circulating levels of melatonin in both species and restored the amplitude of the activity rhythm in the old animals to that of the non-treated young groups. The consumption of a Jerte Valley cherry-based nutraceutical product may help to counteract the impaired activity/rest rhythm found in aged animals. PMID:22074327

Delgado, J; Terrón, M P; Garrido, M; Pariente, J A; Barriga, C; Rodríguez, A B; Paredes, S D

2013-02-01

53

The melatonin rhythm-generating enzyme: molecular regulation of serotonin N-acetyltransferase in the pineal gland.  

Science.gov (United States)

A remarkably constant feature of vertebrate physiology is a daily rhythm of melatonin in the circulation, which serves as the hormonal signal of the daily light/dark cycle: melatonin levels are always elevated at night. The biochemical basis of this hormonal rhythm is one of the enzymes involved in melatonin synthesis in the pineal gland-the melatonin rhythm-generating enzyme-serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, AA-NAT, E.C. 2.3.1.87). In all vertebrates, enzyme activity is high at night. This reflects the influences of internal circadian clocks and of light. The dynamics of this enzyme are remarkable. The magnitude of the nocturnal increase in enzyme activity ranges from 7- to 150-fold on a species-to-species basis among vertebrates. In all cases the nocturnal levels of AA-NAT activity decrease very rapidly following exposure to light. A major advance in the study of the molecular basis of these changes was the cloning of cDNA encoding the enzyme. This has resulted in rapid progress in our understanding of the biology and structure of AA-NAT and how it is regulated. Several constant features of this enzyme have become apparent, including structural features, tissue distribution, and a close association of enzyme activity and protein. However, some remarkable differences among species in the molecular mechanisms involved in regulating the enzyme have been discovered. In sheep, AA-NAT mRNA levels show relatively little change over a 24-hour period and changes in AA-NAT activity are primarily regulated at the protein level. In the rat, AA-NAT is also regulated at a protein level; however, in addition, AA-NAT mRNA levels exhibit a 150-fold rhythm, which reflects cyclic AMP-dependent regulation of expression of the AA-NAT gene. In the chicken, cyclic AMP acts primarily at the protein level and a rhythm in AA-NAT mRNA is driven by a noncyclic AMP-dependent mechanism linked to the clock within the pineal gland. Finally, in the trout, AA-NAT mRNA levels show little change and activity is regulated by light acting directly on the pineal gland. The variety of mechanisms that have evolved among vertebrates to achieve the same goal-a rhythm in melatonin-underlines the important role melatonin plays as the hormonal signal of environmental lighting in vertebrates. PMID:9238858

Klein, D C; Coon, S L; Roseboom, P H; Weller, J L; Bernard, M; Gastel, J A; Zatz, M; Iuvone, P M; Rodriguez, I R; Bégay, V; Falcón, J; Cahill, G M; Cassone, V M; Baler, R

1997-01-01

54

Seasonal Patterns of Melatonin, Cortisol, and Progesterone Secretion in Female Lambs Raised Beneath a 500-KV Transmission Line  

Science.gov (United States)

There is ongoing controversy about the possibility of adverse biological effects from environmental exposures to electric and magnetic fields. These fields are produced by all electrical equipment and appliances including electrical transmission lines. The objective of this environmental science study was to investigate the possible effects of a high voltage transmission line on domestic sheep (Ovis aries L.), a species that can often be found near such lines. The study was primarily designed to determine whether a specific effect of electric and magnetic fields found in laboratory animals also occurs in livestock under natural environmental conditions. The effect is the ability of fields, at levels found in the environment, to significantly depress the normally high nocturnal concentrations of the pineal hormone-melatonin. Ten female Suffolk lambs were penned for 10 months directly beneath a 500-kV transmission line near Estacada, Oregon. Ten other lambs of the same type were penned in a control area away from the transmission line where electric and magnetic fields were at ambient levels. Serum melatonin was analyzed by radioimmunoassay (RIA) from 6618 blood samples collected at 0.5 to 3-hour intervals over eight 48-hour periods. Serum progesterone was analyzed by RIA from blood samples collected twice weekly. Serum cortisol was also assayed by RIA from the blood samples collected during the 48-hour samples. Results showed that lambs in both the control and line groups had the typical pattern of melatonin secretion consisting of low daytime and high nighttime serum concentrations. There were no statistically significant differences between groups in melatonin levels, or in the phase or duration of the nighttime melatonin elevation. Age at puberty and number of reproductive cycles also did not differ between groups. Serum cortisol showed a circadian rhythm with highest concentrations during the day. There were, however, no differences in cortisol concentrations between groups. Statistical analyses on other biological parameters revealed no differences between groups for body weight gain, wool growth, or behavior.

Lee, Jack Monroe, Jr.

55

Clinical aspects of melatonin.  

Directory of Open Access Journals (Sweden)

Melatonin is produced in the human pineal gland, particularly at night, with the circadian rhythm of blood melatonin levels closely paralleling its production within the pineal gland. Light exposure at night, or rapid transmeridian travel severely compromises the circadian production of melatonin. The disturbed melatonin rhythm contributes to jet lag and sleep inefficiency, both of which are improved by melatonin administration. Melatonin is also a highly effective direct free radical scavenger and antioxidant. In this capacity, melatonin reduces experimental cataractogenesis, traumatic injury to the spinal cord and brain, and protects against oxidative damage to neurons and glia in models of stroke, Parkinsonism, and Alzheimer's disease. Additionally, melatonin and its metabolites are highly effective in protecting against ionizing radiation. Finally, melatonin may be a treatment for hypertension. Melatonin's high efficacy, its high safety profile, and its virtual lack of toxicity make it of interest in clinical medicine.

Russel J. Reiter

2008-11-01

56

Effect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease  

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Disturbed sleep is common in chronic obstructive pulmonary disease (COPD). Conventional hypnotics worsen nocturnal hypoxemia and, in severe cases, can lead to respiratory failure. Exogenous melatonin has somnogenic properties in normal subjects and can improve sleep in several clinical conditions. This randomized, double-blind, placebo-controlled study was carried out to determine the effects of melatonin on sleep in COPD. Thirty consecutive patients with moderate to very severe COPD were ini...

Nunes, D. M.; Mota, R. M. S.; Machado, M. O.; Pereira, E. D. B.; Bruin, V. M. S.; Bruin, P. F. C.

2008-01-01

57

Melatonin and the skeleton  

DEFF Research Database (Denmark)

Melatonin may affect bone metabolism through bone anabolic as well as antiresorptive effects. An age-related decrease in peak melatonin levels at nighttime is well documented, which may increase bone resorption and bone loss in the elderly. In vitro, melatonin reduces oxidative stress on bone cells by acting as an antioxidant. Furthermore, melatonin improves bone formation by promoting differentiation of human mesenchymal stem cell (hMSC) into the osteoblastic cell linage. Bone resorption is reduced by increased synthesis of osteoprogeterin (OPG), a decoy receptor that prevents receptor activator of NK-?B ligand (RANKL) in binding to its receptor. Moreover, melatonin is believed to reduce the synthesis of RANKL preventing further bone resorption. In ovariectomized as well as nonovariectomized rodents, melatonin has shown beneficial effects on bone as assessed by biochemical bone turnover markers, DXA, and ?CT scans. Furthermore, in pinealectomized animals, bone mineral density (BMD) is significantly decreasedcompared to controls, supporting the importance of sufficient melatonin levels. In humans, dysfunction of the melatonin signaling pathway may be involved in idiopathic scoliosis, and the increased fracture risk in nighttime workers may be related to changes in the circadian rhythm of melatonin. In the so-far only randomized study on melatonin treatment, no effects were, however, found on bone turnover markers. In conclusion, melatonin may have beneficial effects on the skeleton, but more studies on humans are warranted in order to find out whether supplementation with melatonin at bedtime may preserve bone mass and improve bone biomechanical competence.

Amstrup, A K; Sikjaer, T

2013-01-01

58

Tryptophan affects both gastrointestinal melatonin production and interrenal activity in stressed and nonstressed rainbow trout.  

Science.gov (United States)

The present experiments were designed to test the hypothesis that elevated dietary levels of l-tryptophan (Trp) result in elevated plasma levels of melatonin and that this increase in plasma melatonin concentration is caused by elevated melatonin production and secretion by the gastro-intestinal-tract (GIT). Feeding juvenile rainbow trout (Oncorhynchus mykiss) Trp-supplemented feed for 7 days resulted in elevated daytime plasma levels of melatonin and reduced poststress plasma cortisol concentrations. Nighttime plasma melatonin concentrations were, however, not affected by elevated dietary Trp. Moreover, stress caused a reduction in daytime plasma levels of melatonin in fish fed Trp-supplemented feed, an effect that was counteracted by treatment with an alpha-receptor antagonist. These results clearly suggest that elevated dietary intake of Trp results in an increase in the GIT production of melatonin in rainbow trout. A suggestion that was further supported by the results from an in vitro experiment demonstrating that addition of Trp to the incubation medium stimulates melatonin production and release by incubated rainbow trout GIT. The results from this study led us to suggest a possible mechanism for melatonin in mediating the effects of elevated dietary Trp on poststress plasma cortisol concentrations and aggressive behavior in rainbow trout. PMID:15813903

Lepage, Olivier; Larson, Earl T; Mayer, Ian; Winberg, Svante

2005-05-01

59

Season-dependent postembryonic maturation of the diurnal rhythm of melatonin biosynthesis in the chicken pineal gland.  

Science.gov (United States)

Previously, we have demonstrated that the timing of the nocturnal peak of activity of the pineal arylalkylamine-N-acetyltransferase - a key enzyme in the melatonin biosynthesis pathway - in 3-wk-old chickens kept from the day of hatch under controlled laboratory conditions (L:D 12:12) varies depending on the season of hatch (summer vs. winter). The present study was undertaken to answer the following questions: (1) are season-related differences seen in the level of transcription of genes encoding enzymes of the melatonin biosynthesis pathway? (2) Does the pineal content of the main precursor (serotonin) and the final product (melatonin) exhibit age- and season-related changes? (3) At which step in postembryonic development are these season-related variations in pineal gland function most pronounced? Male Hy-line chickens hatched in the summer or winter, from eggs laid by hens held on L:D 16:8, were kept from the day of hatch under L:D 12:12 conditions. At the age of 2, 9, or 16 d, chickens were sacrificed every 2 h over a 24-h period and their pineal glands, isolated under dim red light, were processed for the measurement of (i) the level of Aanat and Asmt (acetylserotonin O-methyltransferase) mRNAs encoding the two last enzymes involved in melatonin biosynthesis, (ii) the activity of these enzymes, and (iii) the pineal content of serotonin and melatonin. Circadian rhythmicity of all the measured parameters was evaluated by the cosinor method. The levels of Aanat mRNA, AANAT enzymatic activity, and the pineal melatonin content changed during postembryonic development in a manner that was dependent on the season of hatch. Furthermore, the diurnal profile of Asmt mRNA was elevated during the light phase. In "winter" birds, the pattern and amplitude of the diurnal rhythm of accumulation of this transcript did not change with age, while in "summer" birds it increased in an age-related way. In contrast, the enzymatic activity of hydroxyindole-O-methyltransferase (HIOMT; encoded by the Asmt gene) did not change rhythmically, although it increased with age in a season-related way. In "winter" chickens, the pineal serotonin content was low, regardless of age, and did not change rhythmically, whereas in "summer" individuals the serotonin rhythm was already well established by day 2, with the amplitude increasing with age. These results confirm the existence of a "seasonal memory" operating within the chicken pineal gland, although the mechanism(s) underlying this phenomenon have yet to be characterized. PMID:23003334

Piesiewicz, A; Kedzierska, U; Podobas, E; Adamska, I; Zuzewicz, K; Majewski, P M

2012-11-01

60

New developments in the treatment of primary insomnia in elderly patients: focus on prolonged-release melatonin  

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Full Text Available Daniel P Cardinali, María F Vidal, Daniel E VigoDepartment of Teaching and Research, Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, Buenos Aires, ArgentinaAbstract: A temporal relationship between the nocturnal rise in melatonin secretion and the increase in sleep propensity at the beginning of the night, coupled with the sleep-promoting effects of exogenous melatonin, indicate that melatonin is involved in the regulation of sleep. This action is attributed to the MT1 and MT2 melatonin receptors present in the hypothalamic suprachiasmatic nucleus and other brain areas. The sleep-promoting actions of melatonin, which are demonstrable in healthy humans, have been found to be useful in subjects suffering from circadian rhythm sleep disorders and in elderly patients, who had low nocturnal melatonin production and secretion. The effectiveness of melatonin in treating sleep disturbances in these patients is relevant because the sleep-promoting compounds that are usually prescribed, such as benzodiazepines and related drugs, have many adverse effects, such as next-day hangover, dependence, and impairment of memory. Melatonin has been used for improving sleep in patients with insomnia mainly because it does not cause any hangover or show any addictive potential. However, there is a lack of consistency concerning its therapeutic value (partly because of its short half-life and the small quantities of melatonin used. Thus, attention has been focused either on the development of more potent melatonin analogs with prolonged effects or on the design of slow-release melatonin preparations. A prolonged-release preparation of melatonin 2 mg (Circadin® has been approved for the treatment of primary insomnia in patients aged ?55 years in the European Union. This prolonged-release preparation of melatonin had no effect on psychomotor functions, memory recall, or driving skills during the night or the next morning relative to placebo, and was associated with significantly less impairment on many of these tasks relative to zolpidem alone or in combination with prolonged-release melatonin. In 3-week and 6-month randomized, double-blind, clinical trials in patients with primary insomnia aged ?55 years, prolonged-release melatonin was associated with improvements relative to placebo in many sleep and daytime parameters, including sleep quality and latency, morning alertness, and quality of life. Prolonged-release melatonin was very well tolerated in clinical trials in older patients, with a tolerability profile similar to that of placebo. Short-term or longer-term treatment with prolonged-release melatonin was not associated with dependence, tolerance, rebound insomnia, or withdrawal symptoms.Keywords: insomnia, melatonin, Circadin®, clinical trials

Vigo DE

2012-10-01

 
 
 
 
61

Melatonin: functions and ligands.  

Science.gov (United States)

Melatonin is a chronobiotic substance that acts as synchronizer by stabilizing bodily rhythms. Its synthesis occurs in various locations throughout the body, including the pineal gland, skin, lymphocytes and gastrointestinal tract (GIT). Its synthesis and secretion is controlled by light and dark conditions, whereby light decreases and darkness increases its production. Thus, melatonin is also known as the 'hormone of darkness'. Melatonin and analogs that bind to the melatonin receptors are important because of their role in the management of depression, insomnia, epilepsy, Alzheimer's disease (AD), diabetes, obesity, alopecia, migraine, cancer, and immune and cardiac disorders. In this review, we discuss the mechanism of action of melatonin in these disorders, which could aid in the design of novel melatonin receptor ligands. PMID:24792719

Singh, Mahaveer; Jadhav, Hemant R

2014-09-01

62

Radioimmunoassay for Melatonin  

International Nuclear Information System (INIS)

A radioimmunoassay for melatonin has been developed and used to measure the level of melatonin of male and post-menopausal female patients coming to operation for benign and malignant conditions. The amount of melatonin in the serum of the females was considerably lower than that in males. No difference could be found between patients suffering from benign and malignant conditions. A patient with a non-parenchymatous pineal tumour had considerably lower levels in the serum at three months after surgery and radiotherapy. A further month later melatonin could not be found in samples of serum taken over a 24-hour period. (author)

63

Melatonin: both master clock output and internal time-giver in the circadian clocks network.  

Science.gov (United States)

Daily rhythms in physiological and behavioral processes are controlled by a network of circadian clocks, reset by inputs and delivering circadian signals to the brain and peripheral organs. In mammals, at the top of the network is a master clock located in the suprachiasmatic nuclei (SCN) of the hypothalamus, mainly reset by ambient light. The nocturnal synthesis and release of melatonin by the pineal gland are tightly controlled by the SCN clock and inhibited by light exposure. Several roles of melatonin in the circadian system have been identified. As a major hormonal output, melatonin distributes temporal cues generated by the SCN to the multitude of tissue targets expressing melatonin receptors. In some target structures, like the Pars tuberalis of the adenohypophysis, these melatonin signals can drive daily rhythmicity that would otherwise be lacking. In other target structures, melatonin signals are used for the synchronization (i.e., adjustment of the timing of existing oscillations) of peripheral oscillators, such as the fetal adrenal gland. Due to the expression of melatonin receptors in the SCN, endogenous melatonin is also able to feedback onto the master clock, although its physiological significance needs further characterization. Of note, pharmacological treatment with exogenous melatonin can synchronize the SCN clock. From a clinical point of view, provided that the subject is not exposed to light at night, the daily profile of circulating melatonin provides a reliable estimate of the timing of the human SCN. During the past decade, a number of melatonin agonists have been developed for treating circadian, psychiatric and sleep disorders. These drugs may target the SCN for improving circadian timing or act indirectly at some downstream level of the circadian network to restore proper internal synchronization. PMID:21914478

Pevet, Paul; Challet, Etienne

2011-12-01

64

Melatonin influences pancreatic cancerogenesis.  

Science.gov (United States)

Pancreatic cancer has fatal prognosis because of the absence of early symptoms, late diagnosis and the resistance to radio- and chemotherapy. Melatonin, an indoleamine discovered in the pineal gland, has also been detected in the gastrointestinal system and its specific receptors have been identified in the pancreas. Some evidence indicates that melatonin could modulate the process of pancreatic oncogenesis: 1) Melatonin, as direct scavenger of radical oxygen and nitrogen species (ROS and RNS) and activator of antioxidant enzymes effectively protects the pancreatic tissue against oxidative stress and inflammatory damage. 2) In pancreatic carcinoma cell line (PANC-1) melatonin used at high doses affects the Bax/Bcl protein balance, and stimulates the expressions of caspase-9 and caspase-3, thus activating the mitochondrial pathway of apoptosis. On the contrary, low concentrations of melatonin turn on the production of anti-apoptotic heat shock proteins: HSP27, HSP70, and HSP90, which prevents the activation of caspase-3. 3) Melatonin reduces angiogenesis and decreases proliferation of endothelial cells through inhibition of vascular endothelial factor (VEGF). 4) Melatonin strengthens the immune defense of the organism via activation of peripheral effector T cells and suppression of T regulatory cells. 5) In animal studies melatonin has been found to increase the efficacy of oncostatic drugs, to reduce the side effects of chemotherapy and to decrease morbidity. These observations suggest that melatonin at high doses could be potentially taken into consideration as the supportive treatment in the therapy of pancreatic cancer, although the effect of melatonin on apoptosis requires further study. PMID:24258787

Jaworek, Jolanta; Leja-Szpak, Anna

2014-04-01

65

Serum Melatonin in Juvenile Rheumatoid Arthritis: Correlation with Disease Activity  

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Full Text Available The study was conducted to investigate the abnormalities in early morning serum melatonin among patients with Juvenile Rheumatoid Arthritis (JRA and to outline its relation to disease activity and severity. Twenty one patients with JRA and twenty healthy age and sex matched controls were enrolled in the study. Fifteen patients had polyarticular JRA, 3 had oligoarticular and 3 had systemic onset JRA. Evaluation was carried out clinically, functionally and radiologically by using disease activity score, Juvenile Arthritis Functional Assessment Report for Children (JAFAR-C score and modified Larsen score, respectively. Laboratory investigations included Complete Blood Picture (CBC, The Erythrocyte Sedimentation Rate ( ESR, C-Reactive Protein (CRP, classic IgM Rheumatoid Factor (RF, Anti-nuclear Antibodies (ANA and melatonin estimation in serum. The serum levels of melatonin were significantly increased in JRA patients (mean±SD = 13.9±8 pg mL-1 as compared to healthy controls (mean±SD = 8.1±2.7 pg mL-1, p<0.01. A significant positive correlation could link serum melatonin levels to disease activity scores and ESR (r = 0.91, p<0.001 and r = 0.55, p<0.01, respectively. No significant correlation was found between melatonin and either Larsen or JAFAR scores (r = 0.19, r = 0.15, respectively. According to melatonin levels, there were 2 groups of patients: Group I with elevated melatonin level (more than 11 pg mL-1 (n = 15 and group II with normal melatonin level (less than 11 pg mL-1 (n = 6. Patients with elevated melatonin levels had higher ESR (p<0.05, higher disease activity scores (p<0.01 and Larsen scores (p<0.05, than the group of patients with normal serum melatonin. The results of GAFAR scores were comparable between the two groups (p>0.05. Hence the study conclude that the elevated melatonin levels among JRA patients with active synovitis and its close relation to disease activity rather than disease severity suggests that melatonin might play a promoting role in rheumatoid arthritis. Hence, inhibition of its synthesis and/or action by specific antagonists may be of therapeutic value.

Hanaa Mahmoud El-Awady

2007-01-01

66

[Pineal gland melatonin-producing function in elderly patients with hypertensive disease: age peculiarities].  

Science.gov (United States)

This work was aimed at study changes of the epiphyseal melatonin-producing function in elderly patients with hypertensive disease, as well as the relationships of those changes with the degree of arterial hypertension and 24-hour arterial pressure profile disorders. Examination of 18 young (20-34 years) and 20 elderly (60-74 years) healthy people has documented the decrease of melatonin-producing function in aging. In the group of 100 hypertensive disease patients, the nocturnal 6-hydro-oxymelatonin-sulafate (6-HMS) excretion was significantly lower (by 26.5%) than in their healthy age-matched individuals, thus evidencing for more pronounced disturbance of the melatonin-producing function in the former. It is noteworthy that lower melatonin-producing function of the epiphysis was revealed in the patients with the higher level of average 24-hour arterial pressure value and in the patients with a disturbed 24-hour arterial pressure profile "non-dippers". PMID:21510075

Shatilo, V B; Bondarenko, E V; Antoniuk-Shcheglova, I A

2010-01-01

67

Melatonin pretreatment attenuates diazinon-induced testicular damage in mice  

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Full Text Available Background: Diazinon is one of widely used organophosphrous pesticides, can affect both animals and man even after a single exposure. It has a dual toxicity due to acetylcholinestrase inhibition and formation of free oxygen radicals .So, the current work aimed to evaluate the effects of diazinon on the mice testes and the possible protective effect of melatonin. Material and Methods: Male CD-1 adult mice were divided into 6 groups, (1 control group,(2 melatonin group 10mg/kg,(3 diazinon group (30mg/kg, (4 diazinon group (60mg/kg,(5 diazinon 30mg + melatonin and (6 diazinon 60mg/kg + melatonin. Diazinon was orally administrated 1 and 28 days of treatment, whereas, melatonin was administrated intraperitoneally at a single dose. Testicular damage was examined by using hematoxyline and eosin staining. Results: Diazinon treated groups diminished the plasma acetylcholinestrase activity on day 1 of treatment. Morphometrical analysis showed a decrease in seminiferous thickness (day 1 and 28, with increased testicular superoxide dismutase (SOD activity (day28. Melatonin pre-treatment prevented alterations induced by diazinon, except diminution of acetylcholinestrase activity. Conclusion: These results suggest that testicular damage observed post-treatment might be due to elevated concentration of free oxygen radicals (ROS with diazinon while, pretreatment with a single dose of melatonin is a potentially beneficial agent to reduce testicular damage in adult mice probably by decreasing oxidative stress.

El-Mazoudy R. H*. and Abdou H. M

2009-09-01

68

Melatonin promotes superovulation in sika deer (Cervus nippon).  

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In this study, the effects of melatonin (MT) on superovulation and reproductive hormones (melatonin, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and PRL) were investigated in female sika deer. Different doses (40 or 80 mg/animal) of melatonin were subcutaneously implanted into deer before the breeding season. Exogenous melatonin administration significantly elevated the serum FSH levels at the time of insemination compared with levels in control animals. During superovulation, the serum LH levels in donor sika deer reached their highest values (7.1±2.04 ng/mL) at the point of insemination, compared with the baseline levels (4.98±0.07 ng/mL) in control animals. This high level of LH was sustained until the day of embryo recovery. In contrast, the serum levels of PRL in the 80 mg of melatonin-treated group were significantly lower than those of control deer. The average number of corpora lutea in melatonin-treated deer was significantly higher than that of the control (p0.05), which may be related to the relatively small sample size. In addition, embryonic development in melatonin-treated groups was delayed. PMID:25007067

Wang, Liang; Zhuo, Zhi-Yong; Shi, Wen-Qing; Tan, Dun-Xian; Gao, Chao; Tian, Xiu-Zhi; Zhang, Lu; Zhou, Guang-Bin; Zhu, Shi-En; Yun, Peng; Liu, Guo-Shi

2014-01-01

69

Melatonin: exceeding expectations.  

Science.gov (United States)

Melatonin is a small, highly conserved indole with numerous receptor-mediated and receptor-independent actions. Receptor-dependent functions include circadian rhythm regulation, sleep, and cancer inhibition. The receptor-independent actions relate to melatonin's ability to function in the detoxification of free radicals, thereby protecting critical molecules from the destructive effects of oxidative stress under conditions of ischemia/reperfusion injury (stroke, heart attack), ionizing radiation, and drug toxicity, among others. Melatonin has numerous applications in physiology and medicine. PMID:25180262

Reiter, Russel J; Tan, Dun Xian; Galano, Annia

2014-09-01

70

Genetic variability of the pattern of night melatonin blood levels in relation to coat changes development in rabbits  

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Full Text Available Abstract To assess the genetic variability in both the nocturnal increase pattern of melatonin concentration and photoresponsiveness in coat changes, an experiment on 422 Rex rabbits (from 23 males raised under a constant light programme from birth was performed. The animals were sampled at 12 weeks of age, according to 4 periods over a year. Blood samples were taken 7 times during the dark phase and up to 1 h after the lighting began. Maturity of the fur was assessed at pelting. Heritability estimates of blood melatonin concentration (0.42, 0.17 and 0.11 at mid-night, 13 and 15 h after lights-out respectively and strong genetic correlations between fur maturity and melatonin levels at the end of the dark phase (-0.64 indicates that (i the variability of the nocturnal pattern of melatonin levels is under genetic control and (ii the duration of the nocturnal melatonin increase is a genetic component of photoresponsiveness in coat changes.

Chemineau Philippe

2004-03-01

71

Summer and winter cycles in plasma melatonin levels in the elephant seal (Mirounga leonina).  

Science.gov (United States)

Plasma melatonin concentration of immature male elephant seals was determined by radioimmunoassay. Comparison of concentrations during two 24-h periods, one in midsummer and one in midwinter, showed that there was a marked circadian cycle in winter which was greatly modified during the long day length of summer. It is suggested that in summer there was sufficient ambient lighting during the night hours to depress the nocturnal rise in plasma melatonin. The complexity of pineal cycles in the natural environment is stressed, and in this regard the polar regions are of particular interest due to the extreme seasonal changes in day length there. PMID:549553

Griffiths, D; Seamark, R F; Bryden, M M

1979-12-01

72

A 15-minute light pulse during darkness prevents the antigonadotrophic action of afternoon melatonin injections in male hamsters  

Science.gov (United States)

When adult male Syrian hamsters were maintained under 14 h light and 10 h darkness daily (lights on from 0600-2000 h), peak pineal melatonin levels (705 pg/gland) were attained at 0500 h. When the dark phase of the light:dark cycle was interrupted with a 15 min pulse of light from 2300 2315 h (3 h after lights out), the highest melatonin levels achieved was roughly 400 pg/gland. Finally, if the 15 min pulse of light was given at 0200 0215 h (6 h after lights out) the nocturnal rise in pineal melatonin was completely abolished. Having made these observations, a second experiment was designed to determine the ability of afternoon melatonin injections to inhibit reproduction in hamsters kept under an uninterrupted 14?10 cycle or under the same lighting regimen where the dark phase was interrupted with a 15 min pulse of light (0200 0215 h). In the uninterrupted light:dark schedule the daily afternoon injection of 25 ?g melatonin caused the testes and the accessory sex organs to atrophy within 11 weeks. Conversely, if the dark phase was interrupted with light between 0200 0215 h, afternoon melatonin injections were incapable of inhibiting the growth of the reproductive organs. The findings suggest that exogenously administered melatonin normally synergizes with endogenously produced melatonin to cause gonadal involution in hamsters.

Reiter, R. J.; Hurlbut, E. C.; King, T. S.; Richardson, B. A.; Vaughan, M. K.; Kosub, K. Y.

1982-12-01

73

Nocturn and Aubade  

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Full Text Available Nocturne After such a meandering historyOf ramblingAlong water and up the stepsAnd steps and down the treesAnd trees and across the waterAnd round and round the waterfall and fountainAnd kaleidoscopic...

Morteza Dehghani

2012-08-01

74

Nocturn and Aubade  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nocturne After such a meandering historyOf ramblingAlong water and up the stepsAnd steps and down the treesAnd trees and across the waterAnd round and round the waterfall and fountainAnd kaleidoscopic...

Morteza Dehghani

2012-01-01

75

Melatonin and human chronobiology.  

Science.gov (United States)

With the development of accurate and sensitive assays for measuring melatonin in plasma and saliva, it has been possible to advance our understanding of human chronobiology. In particular, the dim light melatonin onset (DLMO) is expected to have an increasingly important role in the diagnosis of circadian phase disorders and their treatment with appropriately timed bright light exposure and/or low-dose melatonin administration. The phase angle difference (PAD) between DLMO and mid-sleep can be used as a marker for internal circadian alignment and may also be used to differentiate individuals who are phase advanced from those who are phase delayed (a long interval indicates the former and a short interval indicates the latter). To provide a corrective phase delay, light exposure should be scheduled in the evening and melatonin should be administered in the morning. To provide a corrective phase advance, light exposure should be scheduled in the morning and melatonin should be administered in the afternoon/evening. The study of patients with seasonal affective disorder (SAD), as well as individuals who are totally blind, has resulted in several findings of interest to basic scientists, as well as psychiatrists and sleep specialists. PMID:18419322

Lewy, A J

2007-01-01

76

Melatonin labeled with hydrogen isotopes  

International Nuclear Information System (INIS)

A study has been made of isotope exchange between melatonin and deuterium (D2O) or tritium (HTO) oxide under different conditions. The ease of isotope exchange for the indole ring hydrogens of melatonin in an acidic medium decreases over the series H4 > H2 H6 >> H7, enabling the authors to process a route for production of melatonin labeled with hydrogen isotopes at positions 4,6, and 2 of the indole ring. A method has been suggested for producing melatonin labeled with hydrogen isotopes at position 2 by desulfurization of 2-(2,4-dinitro-phenylsulfenyl)melatonin at Ni(Re) (D)

77

Melatonin und das kardiovaskuläre System  

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Full Text Available Melatonin, das physiologisch bedeutendste Hormon der Epiphyse, zog nicht zuletzt aufgrund zahlreicher populärer Bücher über seine "wundersamen Effekte" die Aufmerksamkeit auf sich. Synthese und Sekretion von Melatonin werden wesentlich durch den Hell/Dunkel-Zyklus beeinflußt: Trifft Licht auf die Retina, so wird die Melatoninsekretion supprimiert. Melatonin beeinflußt endogene zirkadiane Rhythmen sowie Köpertemperatur und Stimmungslage. In der vorliegenden Arbeit wird das derzeitige Wissen um Interaktionen von Melatonin und dem kardiovaskulären System kritisch beleuchtet. Zusammenfassend muß die Rolle von Melatonin im menschlichen Organismus äußerst kontroversiell betrachtet werden.

Sakotnik A

1999-01-01

78

Melatonin labelled by hydrogen isotopes  

International Nuclear Information System (INIS)

Isotope exchange of melatonin with deuterium (D2O) and tritium (HTO) oxides under different conditions is studied. Simplicity of isotope exchange of hydrogens of the indole ring of melatonin in the acidic medium decreases in series H4>H2>H6>>H7, that permits to suggest the way of melatonin preparation labelled by hydrogen isotopes in positions 4,6 and 2 of the indole ring. The way of melatonin preparation labelled by hydrogen isotopes in position 2 according to the reaction of desulfation 2-(2,4-dinitrophenylsulphenyl) melatonin at catalyst Ni(Re)(D) is suggested

79

Role of Melatonin in Schizophrenia  

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Full Text Available Schizophrenia is a chronic mental disease that disturbs several cognitive functions, such as memory, thought, perception and volition. Schizophrenia’s biological etiology is multifactorial and is still under investigation. Melatonin has been involved in schizophrenia since the first decades of the twentieth century. Research into melatonin regarding schizophrenia has followed two different approaches. The first approach is related to the use of melatonin as a biological marker. The second approach deals with the clinical applications of melatonin as a drug treatment. In this paper, both aspects of melatonin application are reviewed. Its clinical use in schizophrenia is emphasized.

Armando L. Morera-Fumero

2013-04-01

80

Melatonin protection from chronic, low-level ionizing radiation.  

Science.gov (United States)

In the current survey, we summarize the published literature which supports the use of melatonin, an endogenously produced molecule, as a protective agent against chronic, low-level ionizing radiation. Under in vitro conditions, melatonin uniformly was found to protect cellular DNA and plasmid super coiled DNA from ionizing radiation damage due to Cs(137) or X-radiation exposure. Likewise, in an in vivo/in vitro study in which humans were given melatonin orally and then their blood lymphocytes were collected and exposed to Cs(137) ionizing radiation, nuclear DNA from the cells of those individuals who consumed melatonin (and had elevated blood levels) was less damaged than that from control individuals. In in vivo studies as well, melatonin given to animals prevented DNA and lipid damage (including limiting membrane rigidity) and reduced the percentage of animals that died when they had been exposed to Cs(137) or Co(60) radiation. Melatonin's ability to protect macromolecules from the damage inflicted by ionizing radiation likely stems from its high efficacy as a direct free radical scavenger and possibly also due to its ability to stimulate antioxidative enzymes. Melatonin is readily absorbed when taken orally or via any other route. Melatonin's ease of self administration and its virtual absence of toxicity or side effects, even when consumed over very long periods of time, are essential when large populations are exposed to lingering radioactive contamination such as occurs as a result of an inadvertent nuclear accident, an intentional nuclear explosion or the detonation of a radiological dispersion device, i.e., a "dirty" bomb. PMID:22185900

Reiter, Russel J; Korkmaz, Ahmet; Ma, Shuran; Rosales-Corral, Sergio; Tan, Dun-Xian

2011-12-15

 
 
 
 
81

The effect of acute exogenous melatonin on P50 suppression in healthy male volunteers stratified for low and high gating levels  

DEFF Research Database (Denmark)

Sensory gating is frequently found to be disturbed in patients with schizophrenia. In addition, a disruption of the circadian rhythm together with a low nocturnal melatonin output is regularly found in these patients. Since there is some evidence that a brief period of sleep normalizes sensory gating in schizophrenia patients, it is conceivable that their disrupted melatonin level may contribute to the deficits in P50 suppression. In this initial study, the effects of acutely administered melatonin on sensory gating in healthy subjects were investigated. In a double-blind placebo-controlled crossover design, 21 healthy male volunteers were administered melatonin (4 mg) or placebo, after which they were tested in a P50 suppression paradigm. In the group as a whole, melatonin did not affect P50 suppression. However, melatonin increased the P50 ratio in the individuals with high baseline suppression. In contrast to what was expected, melatonin reduced P50 suppression, albeit only in those individuals with high baseline suppression. The current study does not support a beneficial effect of acute exposure to exogenous melatonin on sensory gating. Future research should focus on melatonin's ability to restore basic sleep rhythms and its subsequent effects on sensory gating, in both healthy volunteers and patients with schizophrenia.

Ucar, Ebru; Lehtinen, Emilia K

2012-01-01

82

Nocturnal paroxysmal dystonia.  

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Sleep-related seizures characterised by choreoathetoid, dystonic and ballic movements occurred in 12 patients, repeatedly each night and over a period of years. The nocturnal attacks were short-lasting, responded well to carbamazepine and were sometimes associated with clearly or possibly epileptic seizures during night- or daytime. They resembled the paroxysmal kinesigenic dystonias of wakefulness. Similar dystonic-dyskinetic attacks, but of long duration and unresponsive to medication, were...

Lugaresi, E.; Cirignotta, F.; Montagna, P.

1986-01-01

83

Solid lipid nanoparticles incorporating melatonin as new model for sustained oral and transdermal delivery systems  

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melatonin (MT) is a hormone produced by the pineal gland at night, involved in the regulation of circadian rhythms. For clinical purposes, exogenous MT administration should mimic the typical nocturnal endogenous MT levels, but its pharmacokinetics is not favourable due to short half-life of elimination. Aim of this study is to examine pharmacokinetics of MT incorporated in solid lipid nanoparticles (SLN), administered by oral and transdermal route. SLN peculiarity consists in the possibility...

Mauro, Alessandro; Priano, Lorenzo

2007-01-01

84

Melatonin increases dendritogenesis in the hilus of hippocampal organotypic cultures.  

Science.gov (United States)

Neuropsychiatric disorders are characterized by hippocampus decreased volume and loss of dendrite arborizations in the subiculum and prefrontal cortex. These structural changes are associated with diminished memory performance. Hilar neurons of the hippocampus integrate spatial memory and are lost in dementia. They receive information from dentate gyrus neurons through dendrites, while they send axonal tracts to the CA3 region. Dendrites are complex structures of neurons that receive chemical information from presynaptic and postsynaptic terminals. Melatonin, the main product of the pineal gland, has neuroprotective actions through its free radical-scavenging properties and decreases neuronal apoptosis. Recently, we found that melatonin increases dendrite maturation and complexity in new neurons formed in the dentate gyrus of mice. In addition, in N1E-115 cultured cells, the indole stimulates early stages of neurite formation, a process that is known to antecede dendrite formation and maturation. Thus, in this study, we explored whether melatonin stimulates dendrite formation and complexity in the adult rat hippocampus in organotypic slice cultures, which is a model that preserves the hippocampal circuitry and their tridimensional organizations of connectivity. The effects of melatonin were studied in nonpathological conditions and in the absence of harmful agents. The results showed that the indole at nocturnal concentrations reached in the cerebrospinal fluid stimulates dendritogenesis at formation, growth, and maturation stages. Also, data showed that dendrites formed became competent to form presynaptic specializations. Evidence strongly suggests that melatonin may be useful in the treatment of neuropsychiatric diseases to repair the loss of dendrites and re-establish lost synaptic connections. PMID:22257024

Domínguez-Alonso, Aline; Ramírez-Rodríguez, Gerardo; Benítez-King, Gloria

2012-05-01

85

Stress inhibition of melatonin synthesis in the pineal organ of rainbow trout (Oncorhynchus mykiss) is mediated by cortisol.  

Science.gov (United States)

Cortisol has been suggested to mediate the effect of stress on pineal melatonin synthesis in fish. Therefore, we aimed to determine how pineal melatonin synthesis is affected by exposing rainbow trout to different stressors, such as hypoxia, chasing and high stocking density. In addition, to test the hypothesis that cortisol is a mediator of such stress-induced effects, a set of animals were intraperitoneally implanted with coconut oil alone or containing cortisol (50 mg kg(-1) body mass) and sampled 5 or 48 h post-injection at midday and midnight. The specificity of such effect was also assessed in cultured pineal organs exposed to cortisol alone or with the general glucocorticoid receptor antagonist, mifepristone (RU486). Stress (in particular chasing and high stocking density) affected the patterns of plasma and pineal organ melatonin content during both day and night, with the greatest reduction occurring at night. The decrease in nocturnal melatonin levels in the pineal organ of stressed fish was accompanied by increased serotonin content and decreased AANAT2 enzymatic activity and mRNA abundance. Similar effects on pineal melatonin synthesis to those elicited by stress were observed in trout implanted with cortisol for either 5 or 48 h. These data indicate that stress negatively influences the synthesis of melatonin in the pineal organ, thus attenuating the day-night variations of circulating melatonin. The effect might be mediated by increased cortisol, which binds to trout pineal organ-specific glucocorticoid receptors to modulate melatonin rhythms. Our results in cultured pineal organs support this. Considering the role of melatonin in the synchronization of daily and annual rhythms, the results suggest that stress-induced alterations in melatonin synthesis could affect the availability of fish to integrate rhythmic environmental information. PMID:24436377

López-Patiño, Marcos A; Gesto, Manuel; Conde-Sieira, Marta; Soengas, José L; Míguez, Jesús M

2014-04-15

86

Effect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Disturbed sleep is common in chronic obstructive pulmonary disease (COPD). Conventional hypnotics worsen nocturnal hypoxemia and, in severe cases, can lead to respiratory failure. Exogenous melatonin has somnogenic properties in normal subjects and can improve sleep in several clinical conditions. T [...] his randomized, double-blind, placebo-controlled study was carried out to determine the effects of melatonin on sleep in COPD. Thirty consecutive patients with moderate to very severe COPD were initially recruited for the study. None of the participants had a history of disease exacerbation 4 weeks prior to the study, obstructive sleep apnea, mental disorders, current use of oral steroids, methylxanthines or hypnotic-sedative medication, nocturnal oxygen therapy, and shift work. Patients received 3 mg melatonin (N = 12) or placebo (N = 13), orally in a single dose, 1 h before bedtime for 21 consecutive days. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness was measured by the Epworth Sleepiness Scale. Pulmonary function and functional exercise level were assessed by spirometry and the 6-min walk test, respectively. Twenty-five patients completed the study protocol and were included in the final analysis. Melatonin treatment significantly improved global PSQI scores (P = 0.012), particularly sleep latency (P = 0.008) and sleep duration (P = 0.046). No differences in daytime sleepiness, lung function and functional exercise level were observed. We conclude that melatonin can improve sleep in COPD. Further long-term studies involving larger number of patients are needed before melatonin can be safely recommended for the management of sleep disturbances in these patients.

D.M., Nunes; R.M.S., Mota; M.O., Machado; E.D.B., Pereira; V.M.S., de Bruin; P.F.C., de Bruin.

2008-10-01

87

Effect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease  

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Full Text Available Disturbed sleep is common in chronic obstructive pulmonary disease (COPD. Conventional hypnotics worsen nocturnal hypoxemia and, in severe cases, can lead to respiratory failure. Exogenous melatonin has somnogenic properties in normal subjects and can improve sleep in several clinical conditions. This randomized, double-blind, placebo-controlled study was carried out to determine the effects of melatonin on sleep in COPD. Thirty consecutive patients with moderate to very severe COPD were initially recruited for the study. None of the participants had a history of disease exacerbation 4 weeks prior to the study, obstructive sleep apnea, mental disorders, current use of oral steroids, methylxanthines or hypnotic-sedative medication, nocturnal oxygen therapy, and shift work. Patients received 3 mg melatonin (N = 12 or placebo (N = 13, orally in a single dose, 1 h before bedtime for 21 consecutive days. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI and daytime sleepiness was measured by the Epworth Sleepiness Scale. Pulmonary function and functional exercise level were assessed by spirometry and the 6-min walk test, respectively. Twenty-five patients completed the study protocol and were included in the final analysis. Melatonin treatment significantly improved global PSQI scores (P = 0.012, particularly sleep latency (P = 0.008 and sleep duration (P = 0.046. No differences in daytime sleepiness, lung function and functional exercise level were observed. We conclude that melatonin can improve sleep in COPD. Further long-term studies involving larger number of patients are needed before melatonin can be safely recommended for the management of sleep disturbances in these patients.

D.M. Nunes

2008-10-01

88

Melatonin Inhibits Endoplasmic Reticulum Stress and Epithelial-Mesenchymal Transition during Bleomycin-Induced Pulmonary Fibrosis in Mice  

Science.gov (United States)

Several reports indicate that melatonin alleviates bleomycin (BLM)-induced pulmonary fibrosis in rodent animals. Nevertheless, the exact mechanism remains obscure. The present study investigated the effects of melatonin on endoplasmic reticulum (ER) stress and epithelial-mesenchymal transition (EMT) during BLM-induced lung fibrosis. For the induction of pulmonary fibrosis, mice were intratracheally injected with a single dose of BLM (5.0 mg/kg). Some mice were intraperitoneally injected with melatonin (5 mg/kg) daily for a period of 3 wk. Twenty-one days after BLM injection, lung fibrosis was evaluated. As expected, melatonin significantly alleviated BLM-induced pulmonary fibrosis, as evidenced by Sirius red staining. Moreover, melatonin significantly attenuated BLM-induced EMT to myofibroblasts, as determined by its repression of ?-SMA expression. Further analysis showed that melatonin markedly attenuated BLM-induced GRP78 up-regulation and elevation of the cleaved ATF6 in the lungs. Moreover, melatonin obviously attenuated BLM-induced activation of pulmonary eIF2?, a downstream target of the PERK pathway. Finally, melatonin repressed BLM-induced pulmonary IRE1? phosphorylation. Correspondingly, melatonin inhibited BLM-induced activation of XBP-1 and JNK, two downstream targets of the IRE1 pathway. Taken together, these results suggest that melatonin alleviates ER stress and ER stress-mediated EMT in the process of BLM-induced pulmonary fibrosis. PMID:24818755

Zhao, Hui; Wu, Qing-Qing; Cao, Lin-Feng; Qing, Hou-Ying; Zhang, Cheng; Chen, Yuan-Hua; Wang, Hua; Liu, Rong-Ru; Xu, De-Xiang

2014-01-01

89

Melatonin: Buffering the Immune System  

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Full Text Available Melatonin modulates a wide range of physiological functions with pleiotropic effects on the immune system. Despite the large number of reports implicating melatonin as an immunomodulatory compound, it still remains unclear how melatonin regulates immunity. While some authors argue that melatonin is an immunostimulant, many studies have also described anti-inflammatory properties. The data reviewed in this paper support the idea of melatonin as an immune buffer, acting as a stimulant under basal or immunosuppressive conditions or as an anti-inflammatory compound in the presence of exacerbated immune responses, such as acute inflammation. The clinical relevance of the multiple functions of melatonin under different immune conditions, such as infection, autoimmunity, vaccination and immunosenescence, is also reviewed.

Juan M. Guerrero

2013-04-01

90

Endogenous melatonin and oxidatively damaged guanine in DNA  

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Full Text Available Abstract Background A significant body of literature indicates that melatonin, a hormone primarily produced nocturnally by the pineal gland, is an important scavenger of hydroxyl radicals and other reactive oxygen species. Melatonin may also lower the rate of DNA base damage resulting from hydroxyl radical attack and increase the rate of repair of that damage. This paper reports the results of a study relating the level of overnight melatonin production to the overnight excretion of the two primary urinary metabolites of the repair of oxidatively damaged guanine in DNA. Methods Mother-father-daughter(s families (n = 55 were recruited and provided complete overnight urine samples. Total overnight creatinine-adjusted 6-sulphatoxymelatonin (aMT6s/Cr has been shown to be highly correlated with total overnight melatonin production. Urinary 8-oxo-7,8-dihydro-guanine (8-oxoGua results from the repair of DNA or RNA guanine via the nucleobase excision repair pathway, while urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG may possibly result from the repair of DNA guanine via the nucleotide excision repair pathway. Total overnight urinary levels of 8-oxodG and 8-oxoGua are therefore a measure of total overnight guanine DNA damage. 8-oxodG and 8-oxoGua were measured using a high-performance liquid chromatography-electrospray ionization tandem mass spectrometry assay. The mother, father, and oldest sampled daughter were used for these analyses. Comparisons between the mothers, fathers, and daughters were calculated for aMT6s/Cr, 8-oxodG, and 8-oxoGua. Regression analyses of 8-oxodG and 8-oxoGua on aMT6s/Cr were conducted for mothers, fathers, and daughters separately, adjusting for age and BMI (or weight. Results Among the mothers, age range 42-80, lower melatonin production (as measured by aMT6s/CR was associated with significantly higher levels of 8-oxodG (p Conclusion Low levels of endogenous melatonin production among older individuals may lead to higher levels of oxidatively damaged guanine in DNA, thereby possibly increasing the risk of developing cancer. The possible different effects of melatonin in the rates of utilization of pathways for repair of oxidatively damaged guanine in DNA identified between older women and older men are intriguing.

Poulsen Henrik E

2009-10-01

91

Melatonin Poisoning: A Case Report  

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Full Text Available Melatonin, also known chemically as N-acetyl-5-methoxytryptamine, is produced in the pineal gland from the precursor tryptophan and secreted into the blood. Its exogenous forms are used for the treatment of sleep disorders and jet lag. Melatonin is sold as a sleep drug at pharmacies in Turkey and throughout the world. In this study, we present a case of attempted suicide by the ingestion of melatonin.

Mehmet Gül

2012-10-01

92

Role of Melatonin in Schizophrenia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Schizophrenia is a chronic mental disease that disturbs several cognitive functions, such as memory, thought, perception and volition. Schizophrenia’s biological etiology is multifactorial and is still under investigation. Melatonin has been involved in schizophrenia since the first decades of the twentieth century. Research into melatonin regarding schizophrenia has followed two different approaches. The first approach is related to the use of melatonin as a biological marker. The second a...

Morera-fumero, Armando L.; Pedro Abreu-Gonzalez

2013-01-01

93

Paroxysmal nocturnal hemoglobinuria  

International Nuclear Information System (INIS)

A case of paroxysmal nocturnal hemoglobinuria (PNH) is presented in which MR imaging and CT findings were characteristic. The signal intensity of renal cortex was lower than that of medulla on both T1- and T2-weighted imaging. On CT without contrast enhancement the attenuation of renal cortex was higher than that of renal medulla. These findings at MR imaging and CT were the results of a deposition of hemosiderin in the cells of proximal convoluted tubules, and were helpful for diagnosis of PNH. (orig.)

94

Melatonin Receptor Genes in Vertebrates  

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Full Text Available Melatonin receptors are members of the G protein-coupled receptor (GPCR family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A and MT2 (or Mel1b or MTNR1B receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C, has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.

Hua Dong Yin

2013-05-01

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Chronic fluoxetine treatment increases daytime melatonin synthesis in the rodent  

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Full Text Available Gillian W Reierson, Claudio A Mastronardi, Julio Licinio, Ma-Li WongCenter on Pharmacogenomics, Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USAAbstract: Circadian rhythm disturbances can occur as part of the clinical symptoms of major depressive disorder and have been found to resolve with antidepressant therapy. The pineal gland is relevant to circadian rhythms as it secretes the hormone melatonin following activation of the cyclic adenosine monophosphate (cAMP signaling cascade and of arylalkylamine N-acetyltransferase (AA-NAT, the rate-limiting enzyme for its synthesis. Cyclic AMP is synthesized by adenylate cyclases (AC and degraded by phosphodiesterases (PDEs. Little is known about the contribution of the PDE system to antidepressant-induced alterations in pineal cAMP signaling and melatonin synthesis. In the present study we used enzyme immunoassay to measure plasma melatonin levels and pineal cAMP levels and as well as quantitative real-time polymerase chain reaction to measure pineal expression of PDE, AC, and AA-NAT genes in rats chronically treated with the prototypic antidepressant fluoxetine. We found elevated melatonin synthesis with increased pineal AA-NAT gene expression and daytime plasma melatonin levels and downregulated cAMP signaling with increased PDE and unchanged AC pineal gene expression, and decreased content of pineal cAMP. We conclude that chronic fluoxetine treatment increases daytime plasma melatonin and pineal AA-NAT gene expression despite downregulated pineal cAMP signaling in the rodent.Keywords: antidepressant, melatonin, pineal, nucleotides, cyclic, phosphodiesterase, rat

Gillian W Reierson

2009-09-01

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Melatonin attenuates oxidative stress, liver damage and hepatocyte apoptosis after bile-duct ligation in rats.  

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The goal of this study was to evaluate the possible protective effects of melatonin against cholestatic oxidative stress, liver damage and hepatocyte apoptosis in the common rats with bile duct ligation (BDL). A total of 24 male Wistar albino rats were divided into three groups: control, BDL and BDL + received melatonin; each group contains eight animals. Melatonin-treated BDL rats received daily melatonin 100 mg/kg/day via intraperitoneal injection. The application of BDL clearly increased the malondialdehyde (MDA) levels and decreased the superoxide dismutase (SOD) and glutathione (GSH) activities. Melatonin treatment significantly decreased the elevated tissue MDA levels and increased the reduced SOD and GSH enzyme levels in the tissues. The changes demonstrate that the bile duct proliferation and fibrosis in expanded portal tracts include the extension of proliferated bile ducts into lobules, mononuclear cells and neutrophil infiltration into the widened portal areas as observed in the BDL group. The data indicate that melatonin attenuates BDL-induced cholestatic liver injury, bile duct proliferation and fibrosis. The ?-smooth muscle actin (?-SMA) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in the BDL were observed to be reduced with the melatonin treatment. These results suggest that administration of melatonin is a potentially beneficial agent to reduce liver damage in BDL by decreasing oxidative stress. PMID:23095487

Aktas, Cevat; Kanter, Mehmet; Erboga, Mustafa; Mete, Rafet; Oran, Mustafa

2014-10-01

97

Emergence of naturally occurring melatonin isomers and their proposed nomenclature.  

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Melatonin was considered to be the sole member of this natural family. The emergence of naturally occurring melatonin isomers (MIs) has opened an exciting new research area. Currently, several MIs have been identified in wine, and these molecules are believed to be synthesized by either yeasts or bacteria. A tentative nomenclature for the MIs is proposed in this article. It will be important to explore whether all organisms have the capacity to synthesize MIs, especially under the conditions of environmental stress. These isomers probably share many of the biological functions of melatonin, but their activities seem to exceed those of melatonin. On basis of the limited available information, it seems that MIs differ in their biosynthetic pathways from melatonin. Especially in those compounds in which the aliphatic side chain is not attached to ring atom 3, the starting material may not be tryptophan. Also, the metabolic pathways of MIs remain unknown. This, therefore, is another promising area of research to explore. It is our hypothesis that MIs would increase the performance of yeasts and probiotic bacteria during the processes of fermentation. Therefore, yeasts producing elevated levels of these isomers might have a superior alcohol tolerance and be able to produce higher levels of alcohol. This can be tested by comparing existing yeast strains differing in alcohol tolerance. Selection for MIs may become a strategy for isolating more resistant yeast and Lactobacillus strains, which can be of interest for industrial alcohol production and quality improvements in bacterially fermented foods such as kimchi. PMID:22332602

Tan, Dun-Xian; Hardeland, Ruediger; Manchester, Lucien C; Rosales-Corral, Sergio; Coto-Montes, Ana; Boga, Jose A; Reiter, Russel J

2012-09-01

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Hepatoprotective actions of melatonin: Possible mediation by melatonin receptors  

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Full Text Available Melatonin, the hormone of darkness and messenger of the photoperiod, is also well known to exhibit strong direct and indirect antioxidant properties. Melatonin has previously been demonstrated to be a powerful organ protective substance in numerous models of injury; these beneficial effects have been attributed to the hormone’s intense radical scavenging capacity. The present report reviews the hepatoprotective potential of the pineal hormone in various models of oxidative stress in vivo, and summarizes the extensive literature showing that melatonin may be a suitable experimental substance to reduce liver damage after sepsis, hemorrhagic shock, ischemia/reperfusion, and in numerous models of toxic liver injury. Melatonin’s influence on hepatic antioxidant enzymes and other potentially relevant pathways, such as nitric oxide signaling, hepatic cytokine and heat shock protein expression, are evaluated. Based on recent literature demonstrating the functional relevance of melatonin receptor activation for hepatic organ protection, this article finally suggests that melatonin receptors could mediate the hepatoprotective actions of melatonin therapy.

Alexander M Mathes

2010-12-01

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Medical management of nocturnal enuresis.  

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Nocturnal enuresis, or bedwetting, is the most common cause of urinary incontinence in children. It is known to have a significant psychosocial impact on the child as well as the family. Nocturnal enuresis typically presents as failure to become dry at night after successful daytime toilet training. It can be primary or secondary (developing after being successfully dry at night for at least 6 months). Children with nocturnal enuresis may have excessive nocturnal urine production, poor sleep arousal and/or reduced bladder capacity. Alarm therapy is the recommended first-line therapy, with treatment choices being influenced by the presence or absence of the abnormalities mentioned above. Children with nocturnal enuresis may also have daytime urinary urgency, frequency or incontinence of urine. This group (non-monosymptomatic nocturnal enuresis) requires a different clinical approach, with a focus on treating daytime bladder symptoms, which commonly involves pharmacotherapy with anticholinergic medications and urotherapy (including addressing bowel problems). This review discusses the current management of nocturnal enuresis using the terminologies recommended by the International Children's Continence Society. PMID:22168597

Deshpande, Aniruddh V; Caldwell, Patrina H Y

2012-04-01

100

The function of nocturnal transpiration  

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Nocturnal transpiration is an important source of water loss, accounting for up to 25% of daytime transpiration in some species. Nocturnal water losses cannot be explained under the prevailing 'paradigm' of optimizing carbon gain while minimizing water loss because carbon fixation does not occur at night. Alternative explanations regarding the function and potential evolutionary advantage of nocturnal transpiration have been proposed, such as enhanced nutrient uptake and transport or delivery of O2 to parenchyma cells for respiration. However, recent evidence suggests that the role of nocturnal transpiration in supplementing the overall plant nutrient budget is relatively small, and the O2 hypothesis is difficult to test experimentally. Here, we propose that the main function of nocturnal transpiration (and water transport) is to prevent catastrophic xylem failure by restoring depleted stem 'capacitors' and enhancing early morning CO2 uptake, as stomata 'prepare' for daytime conditions. Nocturnal sap flux was highest in Eucalyptus grandis trees in the field following a heat wave (reaching 47C with VPDs > 8kPa in the daytime) generating maximal daytime water losses compared with cooler and lower VPD periods, indicating the importance of nocturnal stomatal conductance for stem refilling. Moreover, we observed that the time for stomata to respond to light early in the morning (dawn) across 25 different genotypes of E. camaldulensis in a glasshouse was shortest in those genotypes with highest nocturnal stomatal conductance, which was also correlated with higher daytime photosynthesis. This observation is consistent with previous observations that nocturnal stomatal conductance is partially controlled by the clock, which is utilised to anticipate daytime conditions. Data from the literature suggests that eucalypts respond similarly to other C3 species, suggesting that mechanisms regulating night-time transpiration may be universal.

Pfautsch, Sebastian; Resco de Dios, Víctor; Loik, Michael; Tissue, David

2014-05-01

 
 
 
 
101

Nocturnal frontal lobe epilepsy.  

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Nocturnal frontal lobe epilepsy (NFLE) is a syndrome of heterogeneous etiology, characterized by the occurrence of sleep-related seizures with different complexity and duration. Genetic, lesional, and cryptogenetic NFLE forms have been described. NFLE is generally considered a benign clinical entity, although severe, drug-resistant forms do exist. A significant proportion of sleep-related complex motor seizures, hardly distinguishable from NFLE, originate outside the frontal lobe. Moreover, the distinction of NFLE from the non-rapid eye movement arousal parasomnias may be challenging. A correct diagnosis of NFLE should be based on a diagnostic approach that includes the anamnestic, video-polysomnographic, morphological, and genetic aspects. Studies on the relationships between genes, arousal regulatory mechanisms, and epileptogenesis, using both clinical and experimental models of NFLE might provide key insights in the interrelationship between sleep and epilepsy. PMID:24395520

Nobili, Lino; Proserpio, Paola; Combi, Romina; Provini, Federica; Plazzi, Giuseppe; Bisulli, Francesca; Tassi, Laura; Tinuper, Paolo

2014-02-01

102

Melatonin in traditional Mediterranean diets.  

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Compared with other industrialized countries, the lower incidence of chronic-degenerative disorders in Mediterranean populations has been emphasized in recent decades. The health-promoting effects arising from Mediterranean dietary habits have been attributed to the large intake of plant foodstuffs rich in bioactive phytochemicals, such as melatonin. Recently, it has been suggested that melatonin present in edible plants may improve human health, by virtue of its biological activities and its good bioavailability. Plant melatonin, besides contributing to optimize the physiological functions regulated, in humans, by endogenous melatonin, may be involved in nutritional therapy to reduce the risk of cancer, cardiovascular and neurodegenerative diseases in western populations. In this view, the presence of melatonin in some Mediterranean foods and beverages adds a new element to the hypothesis of health benefits associated to Mediterranean dietary patterns, although the available data are still preliminary and incomplete. PMID:20536683

Iriti, Marcello; Varoni, Elena M; Vitalini, Sara

2010-09-01

103

MELATONIN: A PLEIOTROPIC MOLECULE REGULATING INFLAMMATION  

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Abstract Melatonin is a neurohormone produced by the pineal gland that regulates sleep and circadian functions. Melatonin also regulates inflammatory and immune processes acting as both an activator and inhibitor of these responses. Melatonin demonstrates endocrine, but also paracrine and autocrine effects in the leukocyte compartment: on one side, leukocytes respond to melatonin in a circadian fashion; on the other side, leukocytes are able to synthesize melatonin by themselves. W...

2010-01-01

104

Melatonin reduces cardiac remodeling and improves survival in rats with isoproterenol-induced heart failure.  

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Melatonin was previously shown to reduce blood pressure and left ventricular (LV) remodeling in several models of experimental heart damage. This study investigated whether melatonin prevents LV remodeling and improves survival in isoproterenol-induced heart failure. In the first experiment, four groups of 3-month-old male Wistar rats (12 per group) were treated for 2 wk as follows: controls, rats treated with melatonin (10 mg/kg/day) (M), rats treated with isoproterenol (5 mg/kg/day intraperitoneally the second week) (Iso), and rats treated with melatonin (2 wk) and isoproterenol (the second week) in corresponding doses (IsoM). In the second experiment, 30 rats were treated with isoproterenol and 30 rats with isoproterenol plus melatonin for a period of 28 days and their mortality was investigated. Isoproterenol-induced heart failure with hypertrophy of the left and right ventricles (LV, RV), lowered systolic blood pressure (SBP) and elevated pulmonary congestion. Fibrotic rebuilding was accompanied by alterations of tubulin level in the LV and oxidative stress development. Melatonin failed to reduce the weight of the LV or RV; however, it curtailed the weight of the lungs and attenuated the decline in SBP. Moreover, melatonin decreased the level of oxidative stress and of insoluble and total collagen and partly prevented the beta-tubulin alteration in the LV. Most importantly, melatonin reduced mortality and prolonged the average survival time. In conclusion, melatonin exerts cardioprotective effects and improves outcome in a model of isoproterenol-induced heart damage. The antiremodeling effect of melatonin may be of potential benefit in patients with heart failure. PMID:24942291

Simko, Fedor; Bednarova, Kristina Repova; Krajcirovicova, Kristina; Hrenak, Jaroslav; Celec, Peter; Kamodyova, Natalia; Gajdosechova, Lucia; Zorad, Stefan; Adamcova, Michaela

2014-09-01

105

Relevance of the chronobiological and non-chronobiological actions of melatonin for enhancing therapeutic efficacy in neurodegenerative disorders.  

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Melatonin is an indolamine with a large spectrum of functions that can be divided into chronobiotic and nonchronobiotic. Chronobiotic effects are mediated by the daily rhythm of melatonin in the plasma due to nocturnal pineal synthesis, whereas the melatonin produced by other cells, such as gastrointestinal and immune competent cells, is independent of the light/dark cycle and exert non-chronobiotic effects. The concentrations achieved by the two sources are significantly different, varying in the pM-nM range in the plasma, and may achieve concentrations in the mM range when released locally by activated immune-competent cells. Consequently, the effects of the melatonin produced in these two situations are distinct. Much has been reported about the beneficial response to exogenous melatonin administration in several pathological conditions. However, the relationship between the establishment of a disease and the state of the physiological activity of the pineal gland is still poorly understood. Here, we review the state of art in the modulation of pineal melatonin synthesis, relevant patents, and discuss its relationship with neurodegenerative disorders that involve a central inflammatory response, such as Alzheimer's disease, to suggest the putative relevance of new therapeutic protocols that replace this pineal hormone. PMID:22074584

Cecon, Erika; Markus, Regina P

2011-05-01

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Distinct Expression Profiles of Three Melatonin Receptors during Early Development and Metamorphosis in the Flatfish Solea senegalensis  

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Full Text Available Melatonin actions are mediated through G protein-coupled transmembrane receptors. Recently, mt1, mt2, and mel1c melatonin receptors were cloned in the Senegalese sole. Here, their day-night and developmental expressions were analyzed by quantitative PCR. These results revealed distinct expression patterns of each receptor through development. mel1c transcripts were more abundant in unfertilized ovulated oocytes and declined during embryonic development. mt1 and mt2 expression was higher at the earliest stages (2–6 days post-fertilization, decreasing before (mt2 or during (mt1 metamorphosis. Only mt1 and mel1c expression exhibited day-night variations, with higher nocturnal mRNA levels. These results suggest different roles and transcriptional regulation of these melatonin receptors during flatfish development and metamorphosis.

Olivier Lan-Chow-Wing

2014-11-01

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Distinct Expression Profiles of Three Melatonin Receptors during Early Development and Metamorphosis in the Flatfish Solea senegalensis.  

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Melatonin actions are mediated through G protein-coupled transmembrane receptors. Recently, mt1, mt2, and mel1c melatonin receptors were cloned in the Senegalese sole. Here, their day-night and developmental expressions were analyzed by quantitative PCR. These results revealed distinct expression patterns of each receptor through development. mel1c transcripts were more abundant in unfertilized ovulated oocytes and declined during embryonic development. mt1 and mt2 expression was higher at the earliest stages (2-6 days post-fertilization), decreasing before (mt2) or during (mt1) metamorphosis. Only mt1 and mel1c expression exhibited day-night variations, with higher nocturnal mRNA levels. These results suggest different roles and transcriptional regulation of these melatonin receptors during flatfish development and metamorphosis. PMID:25402642

Lan-Chow-Wing, Olivier; Confente, Francesca; Herrera-Pérez, Patricia; Isorna, Esther; Chereguini, Olvido; Rendón, Maria Del Carmen; Falcón, Jack; Muñoz-Cueto, José A

2014-01-01

108

Effects of orexigenic peptides and leptin on melatonin secretion during different photoperiods in seasonal breeding ewes: an in vitro study.  

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The pineal gland (PG) acts as a neuroendocrine transducer of daily and seasonal time through the nocturnal release of melatonin. Here, we examined the interaction of season, orexin, ghrelin, and leptin on melatonin secretion by pineal explants in short-term culture. Glands were collected after sunset from 12 ewes during long days (LD; April and May) and from an additional 12 ewes during short days (SD; October and November). Glands were transected sagittally into strips, with each equilibrated in 2.5 mL of Dulbecco's modified Eagle's medium for 60 min, followed by a 2-h incubation in control medium or medium containing orexin B (10 and 100 ng/mL), ghrelin (10 and 100 ng/mL), or 50 ng/mL of leptin. After a 3-h incubation, some PG explants treated previously with lower doses of orexin or ghrelin were challenged with 50 ng/mL of leptin and those treated with both doses of orexin were challenged with 300 nM of the ?-agonist isoproterenol. One milliliter of medium was harvested and replaced from each well every 30 min. Treatment with the low dose of orexin during LD increased melatonin secretion about 110% (P<0.01); treatment with a high dose increased melatonin secretion about 47% (P<0.001). During the SD period, leptin stimulated (P < 0.05) melatonin secretion slightly compared with mean melatonin concentration in controls. However, together, orexin and leptin depressed (P<0.01) melatonin secretion. Both doses of ghrelin reduced (P < 0.01) melatonin concentration during the SD season compared with control culture. Addition of ghrelin and leptin to culture medium increased (P<0.01) melatonin concentration compared with ghrelin-treated culture and decreased melatonin concentration (P<0.01) compared with leptin-treated culture during SD. Isoproterenol stimulated (P<0.01) melatonin secretion compared with values observed during the pretreatment period. We conclude that orexigenic peptides (orexin B and ghrelin) and an anorectic peptide (leptin) affect PG directly. The responses of PG to those hormones depend on day length. Moreover, secretion of melatonin from the ovine PG is under an adrenergic regulation. PMID:21185681

Zieba, D A; Kirsz, K; Molik, E; Romanowicz, K; Wojtowicz, A K

2011-04-01

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Analyzing nocturnal noise stratification.  

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Pollution associated to traffic can be considered as one of the most relevant pollution sources in our cities; noise is one of the major components of traffic pollution; thus, efforts are necessary to search adequate noise assessment methods and low pollution city designs. Different methods have been proposed for the evaluation of noise in cities, including the categorization method, which is based on the functionality concept. Until now, this method has only been studied (with encouraging results) for short-term, diurnal measurements, but nocturnal noise presents a behavior clearly different on respect to the diurnal one. In this work 45 continuous measurements of approximately one week each in duration are statistically analyzed to identify differences between the proposed categories. The results show that the five proposed categories highlight the noise stratification of the studied city in each period of the day (day, evening, and night). A comparison of the continuous measurements with previous short-term measurements indicates that the latter can be a good approximation of the former in diurnal period, reducing the resource expenditure for noise evaluation. Annoyance estimated from the measured noise levels was compared with the response of population obtained from a questionnaire with good agreement. The categorization method can yield good information about the distribution of a pollutant associated to traffic in our cities in each period of the day and, therefore, is a powerful tool for town planning and the design of pollution prevention policies. PMID:24548881

Rey Gozalo, Guillermo; Barrigón Morillas, Juan Miguel; Gómez Escobar, Valentín

2014-05-01

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Monosymptomatic nocturnal enuresis  

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Full Text Available Enuresis Nocturna is the most common urologic problemin childhood. There is not a consensus about terminology.Terminology identified by The International Children’sContinence Society (ICCS is recommended. Bed-wettingat night during sleep (incontinence in children above 5years of age who don’t have congenital or acquired centralnervous system defect is defined as enuresis nocturna.There are two groups monosymptomatic (simpleand non-monosymptomatic (complicated. Monosymptomaticenuresis nocturna (MNE has no symptoms otherthan bed-wetting at night during sleep. Various theoriesconcerning etiology of MNE has been suggested; one ormore of genetic, hormonal, bladder associated and sleepdisorders are stated to play a role. Self-improvement canbe achieved each year by 15% increasing maturity. Underpinning treatment and in addition to this unique treatmentmust be done by considering the factors in the pathophysiology.The success of the treatment and roadmapto be followed must be arrange with child and family. Thepurpose of this eclectic is; evaluation of correct diagnosis,differential diagnosis, patient follow-up and treatment optionsof the cases applicant with nocturnal enuresis basedon the current knowledge of ICCS and Turkey EnuresisTreatment Guide.

Bertan Karabo?a

2012-03-01

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Review of disrupted sleep patterns in Smith-Magenis syndrome and normal melatonin secretion in a patient with an atypical interstitial 17p11.2 deletion.  

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Smith-Magenis syndrome (SMS) is a disorder characterized by multiple congenital anomalies and behavior problems, including abnormal sleep patterns. It is most commonly due to a 3.5 Mb interstitial deletion of chromosome 17 band p11.2. Secretion of melatonin, a hormone produced by the pineal gland, is the body's signal for nighttime darkness. Published reports of 24-hr melatonin secretion patterns in two independent SMS cohorts (US and France) document an inverted endogenous melatonin pattern in virtually all cases (96%), suggesting that this finding is pathognomic for the syndrome. We report on a woman with SMS due to an atypical large proximal deletion ( approximately 6Mb; cenTNFRSFproteinB) of chromosome band (17)(p11.2p11.2) who presents with typical sleep disturbances but a normal pattern of melatonin secretion. We further describe a melatonin light suppression test in this patient. This is the second reported patient with a normal endogenous melatonin rhythm in SMS associated with an atypical large deletion. These two patients are significant because they suggest that the sleep disturbances in SMS cannot be solely attributed to the abnormal diurnal melatonin secretion versus the normal nocturnal pattern. PMID:19530184

Boudreau, Eilis A; Johnson, Kyle P; Jackman, Angela R; Blancato, Jan; Huizing, Marjan; Bendavid, Claude; Jones, Marypat; Chandrasekharappa, Settara C; Lewy, Alfred J; Smith, Ann C M; Magenis, R Ellen

2009-07-01

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Methylphenidate Ameliorates Depressive Comorbidity in ADHD Children without any Modification on Differences in Serum Melatonin Concentration between ADHD Subtypes  

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Full Text Available The vast majority of Attention-deficit/hyperactivity disorder (ADHD patients have other associated pathologies, with depressive symptoms as one of the most prevalent. Among the mediators that may participate in ADHD, melatonin is thought to regulate circadian rhythms, neurological function and stress response. To determine (1 the serum baseline daily variations and nocturnal excretion of melatonin in ADHD subtypes and (2 the effect of chronic administration of methylphenidate, as well as the effects on symptomatology, 136 children with ADHD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision: DSM-IV-TR criteria were divided into subgroups using the “Children’s Depression Inventory” (CDI. Blood samples were drawn at 20:00 and 09:00 h, and urine was collected between 21:00 and 09:00 h, at inclusion and after 4.61 ± 2.29 months of treatment. Melatonin and its urine metabolite were measured by radioimmunoassay RIA. Factorial analysis was performed using STATA 12.0. Melatonin was higher predominantly in hyperactive-impulsive/conduct disordered children (PHI/CD of the ADHD subtype, without the influence of comorbid depressive symptoms. Methylphenidate ameliorated this comorbidity without induction of any changes in the serum melatonin profile, but treatment with it was associated with a decrease in 6-s-melatonin excretion in both ADHD subtypes. Conclusions: In untreated children, partial homeostatic restoration of disrupted neuroendocrine equilibrium most likely led to an increased serum melatonin in PHI/CD children. A differential cerebral melatonin metabolization after methylphenidate may underlie some of the clinical benefit.

Isabel Cubero-Millán

2014-09-01

113

Methylphenidate Ameliorates Depressive Comorbidity in ADHD Children without any Modification on Differences in Serum Melatonin Concentration between ADHD Subtypes  

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The vast majority of Attention-deficit/hyperactivity disorder (ADHD) patients have other associated pathologies, with depressive symptoms as one of the most prevalent. Among the mediators that may participate in ADHD, melatonin is thought to regulate circadian rhythms, neurological function and stress response. To determine (1) the serum baseline daily variations and nocturnal excretion of melatonin in ADHD subtypes and (2) the effect of chronic administration of methylphenidate, as well as the effects on symptomatology, 136 children with ADHD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision: DSM-IV-TR criteria) were divided into subgroups using the “Children’s Depression Inventory” (CDI). Blood samples were drawn at 20:00 and 09:00 h, and urine was collected between 21:00 and 09:00 h, at inclusion and after 4.61 ± 2.29 months of treatment. Melatonin and its urine metabolite were measured by radioimmunoassay RIA. Factorial analysis was performed using STATA 12.0. Melatonin was higher predominantly in hyperactive-impulsive/conduct disordered children (PHI/CD) of the ADHD subtype, without the influence of comorbid depressive symptoms. Methylphenidate ameliorated this comorbidity without induction of any changes in the serum melatonin profile, but treatment with it was associated with a decrease in 6-s-melatonin excretion in both ADHD subtypes. Conclusions: In untreated children, partial homeostatic restoration of disrupted neuroendocrine equilibrium most likely led to an increased serum melatonin in PHI/CD children. A differential cerebral melatonin metabolization after methylphenidate may underlie some of the clinical benefit. PMID:25257531

Cubero-Millan, Isabel; Molina-Carballo, Antonio; Machado-Casas, Irene; Fernandez-Lopez, Luisa; Martinez-Serrano, Sylvia; Tortosa-Pinto, Pilar; Ruiz-Lopez, Aida; Luna-del-Castillo, Juan-de-Dios; Uberos, Jose; Munoz-Hoyos, Antonio

2014-01-01

114

Pinealectomy, melatonin, and courtship behavior in male red-sided garter snakes (Thamnophis sirtalis parietalis).  

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Activation of courtship behavior in male red-sided garter snakes is independent of androgens. Only exposure to extended periods of low temperature with subsequent warming stimulates courtship in males. The pineal gland is thought to transduce temperature as well as photoperiodic information in reptiles. Therefore, we explored the relationship of the pineal and melatonin to sexual behavior in this species. Pinealectomy of male garter snakes disrupted sexual behavior upon emergence from a 17-week period of low temperature in approximately 60% of treated individuals in each of the 3 years of study. However, 40% of the males were unaffected by the pinealectomy, engaging in vigorous courtship. Administration of exogenous, chronic melatonin did not significantly modulate the effect of pinealectomy. Upon pinealectomy in the autumn (before hibernation), plasma levels of melatonin fell. However, upon emergence from hibernation, melatonin levels in pinealectomized (PINX) and sham-treated (SHAM) animals were equivalent, indicating extrapineal source(s) of melatonin. However, PINX males did not exhibit a diel cycle in melatonin levels upon emergence. Instead, melatonin remained elevated through the subsequent 24-hr period. SHAMs did exhibit a diel cycle. Ten days after emergence, PINX animals either had a disrupted/abnormal melatonin cycle and were non-courters or had a cycle similar to SHAM males and courted. Therefore, a normal diel cycle of melatonin appeared necessary for the proper expression of courtship behavior. These results suggest that the pineal in snakes 1) is part of a complex, multi-oscillator system as it is in birds and lizards and 2) may play a role in maintaining polymorphism in timing of reproductive behavior. PMID:8583209

Mendonça, M T; Tousignant, A J; Crews, D

1996-01-01

115

Regularly scheduled, day-time, slow-onset 60 Hz electric and magnetic field exposure does not depress serum melatonin concentration in nonhuman primates  

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Experiments conducted with laboratory rodents indicate that exposure to 60 Hz electric fields or magnetic fields can suppress nocturnal melatonin concentrations in pineal gland and blood. In three experiments employing three field-exposed and three sham-exposed nonhuman primates, each implanted with an indwelling venous cannula to allow repeated blood sampling, the authors studied the effects of either 6 kV/m and 50 {micro}T (0.5 G) or 30 kV/m and 100 {micro}T (1.0 G) on serum melatonin patterns. The fields were ramped on and off slowly, so that no transients occurred. Extensive quality control for the melatonin assay, computerized control and monitoring of field intensities, and consistent exposure protocols were used. No changes in nocturnal serum melatonin concentration resulted from 6 weeks of day-time exposure with slow field onset/offset and a highly regular exposure protocol. These results indicate that, under the conditions tested, day-time exposure to 60 Hz electric and magnetic fields in combination does not result in melatonin suppression in primates.

Rogers, W.R.; Smith, H.D.; Orr, J.L. [Southwest Research Inst., San Antonio, TX (United States); Reiter, R.J.; Barlow-Walden, L. [Univ. of Texas Health Science Center, San Antonio, TX (United States)

1995-12-31

116

Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats.  

Science.gov (United States)

The increased breast cancer risk in female night shift workers has been postulated to result from the suppression of pineal melatonin production by exposure to light at night. Exposure of rats bearing rat hepatomas or human breast cancer xenografts to increasing intensities of white fluorescent light during each 12-hour dark phase (0-345 microW/cm2) resulted in a dose-dependent suppression of nocturnal melatonin blood levels and a stimulation of tumor growth and linoleic acid uptake/metabolism to the mitogenic molecule 13-hydroxyoctadecadienoic acid. Venous blood samples were collected from healthy, premenopausal female volunteers during either the daytime, nighttime, or nighttime following 90 minutes of ocular bright, white fluorescent light exposure at 580 microW/cm2 (i.e., 2,800 lx). Compared with tumors perfused with daytime-collected melatonin-deficient blood, human breast cancer xenografts and rat hepatomas perfused in situ, with nocturnal, physiologically melatonin-rich blood collected during the night, exhibited markedly suppressed proliferative activity and linoleic acid uptake/metabolism. Tumors perfused with melatonin-deficient blood collected following ocular exposure to light at night exhibited the daytime pattern of high tumor proliferative activity. These results are the first to show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night. These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers. PMID:16322268

Blask, David E; Brainard, George C; Dauchy, Robert T; Hanifin, John P; Davidson, Leslie K; Krause, Jean A; Sauer, Leonard A; Rivera-Bermudez, Moises A; Dubocovich, Margarita L; Jasser, Samar A; Lynch, Darin T; Rollag, Mark D; Zalatan, Frederick

2005-12-01

117

Tritiation of melatonin by several methods  

International Nuclear Information System (INIS)

The hormone melatonin acts at several G protein-linked receptors to cause a myriad of significant physiological effects. The tritiation of melatonin at high specific activity and characterization of it with tritium NMR for biological testing is reported. (author)

118

[Melatonin regulates ovarian function: an update].  

Science.gov (United States)

Melatonin (N-acetyl-5-methoxytryptamine, MT) is a hormone synthesized and secreted by the pineal gland. Recent studies show that melatonin plays an essential role in the pathogenesis of many reproductive processes. High-concentration melatonin exists in human preovulatory follicular fluid and melatonin receptors are present in ovarian granulosa cells, which indicates the direct effects of melatonin on ovarian function. Reactive oxygen species are involved in a number of reproductive events, including folliculogenesis, follicular atresia, ovulation, oocyte maturation, and corpus luteum formation. Melatonin and its metabolites, as powerful antioxidants and free radical scavengers, can potentially inhibit premature ovarian failure. Literature published in recent years shows the essential roles of melatonin in improving human ovarian function and oocyte quality as well as in the management of infertility. Researches on the action mechanisms of melatonin may provide a theoretical basis for the prevention and treatment of some clinical diseases. PMID:25029864

Zhang, Liang; Liang, Yuan-Jiao

2014-06-01

119

Thermal sensitivity of reptilian melatonin rhythms: "cold" tuatara vs. "warm" skink.  

Science.gov (United States)

Daily rhythms in plasma melatonin levels were compared in two ecologically diverse reptilian species under natural environmental conditions in autumn. The nocturnal, cold temperature-adapted tuatara (Sphenodon punctatus) had a melatonin rhythm of much lower amplitude than did the diurnal desert-adapted sleepy lizard (Tiliqua rugosa). Experiments in controlled laboratory environments showed that, although both species are capable of attaining a comparable melatonin peak (approximately 750 pmol/l), the threshold temperature at which a significant daily rhythm occurs is approximately 15 degrees C in S. punctatus compared with approximately 25 degrees C in T. rugosa. This difference probably reflects the disparate thermoregulatory adaptations of the two species, S. punctatus favoring mean activity temperatures of 11.5 degrees C and T. rugosa, 32.5 degrees C. In ectotherms such as reptiles, therefore, species-typical thermoregulatory behavior may provide thermal cues that interact with photoperiod to provide the appropriate melatonin signal for the regulation of annual physiological cycles. PMID:2719158

Firth, B T; Thompson, M B; Kennaway, D J; Belan, I

1989-05-01

120

Nocturnal 6-hydroxymelatonin sulfate excretion in female workers exposed to magnetic fields  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study was to determine whether daytime occupational exposure to extremely low frequency magnetic fields (MFs) suppresses nocturnal melatonin production. Sixty female volunteers were recruited. Thirty-nine worked in a garment factory, and 21 office workers served as a reference group. Exposure assessment was based on the type of sewing machine used and MF measurements around each type of machine. Eye-level MF flux density was used to classify the operators to higher (> 1 microT) and lower (0.3-1 microT) exposure categories. A third group of factory workers had diverse MF exposures from other sources. The reference group had average exposure of about 0.15 microT. Urine samples were collected on Friday and Monday for three consecutive weeks. Melatonin production was assessed as urinary 6-hydroxymelatonin sulfate (6-OHMS) excretion. The ratio of Friday morning/Monday morning 6-OHMS was used to test the hypothesis that melatonin production is suppressed after 4 days of occupational MF exposure with significant recovery during the weekend. Possible chronic suppression of melatonin production was evaluated by studying exposure-related differences in the Friday values by multivariate regression analysis. The Monday/Friday ratios were close to 1.0, suggesting that there is no increase in melatonin production over the weekend. The average 6-OHMS excretion on Friday was lower among the factory workers than in the reference group, but no monotonous dose-response was observed. Multivariate regression analysis identified MF exposure, smoking, and age as significant explanatory variables associated with decreased 6-OHMS excretion.

Juutilainen, J (Kuopio, University of); Stevens, Richard G.(BATTELLE (PACIFIC NW LAB)); Anderson, Larry E.(BATTELLE (PACIFIC NW LAB)); Hansen, Norman H.(WAVEID); Kilpelainen, M (Kuopio, University of); Kumlin, T (Kuopio, University of); Laitinen, J T.(Kuopio, University of); Sobell, Eugene (Southern California, Univ Of); Wilson, Bary W.(BATTELLE (PACIFIC NW LAB))

2000-03-15

 
 
 
 
121

Electric power, melatonin, and breast cancer  

International Nuclear Information System (INIS)

In this paper, the epidemiology of breast cancer will be discussed, followed by a brief description of the effect of electric fields on melatonin and the relation of melatonin to mammary cancer in rats. Finally, there will be a consideration of factors such as alcohol that affect melatonin and their relation to breast cancer risk. 55 refs

122

The effect of night illumination, red and infrared light, on locomotor activity, behaviour and melatonin of Senegalese sole (Solea senegalensis) broodstock.  

Science.gov (United States)

The present study aimed to determine a non-invasive nocturnal lighting system for the behavioural observation of a highly light sensitive species, Senegalese sole (Solea senegalensis). Locomotor activity, four types of behaviour and plasma melatonin were analysed in groups of 12 adult Senegalese sole (Solea senegalensis) reared in captivity and held under four night illumination treatments: total darkness (control), high 50lux intensity red light (group RH), low 5lux intensity red light (group RL) and infrared light (group IR). All groups experienced the same conditions during the day (lights on from 07:00 to 19:00) with white lighting of 125lux. Clarity of video images taken at night for the observation of fish behaviour were ranked as follows: group RH>RL>IR>control. All treatments presented a daily rhythm in locomotor activity with high activity from 14:00 to 18:00 and low activity from 21:00 to 12:00. The sole exposed to the high intensity red light at night appeared to be disturbed as during the low nocturnal locomotor activity period group RH presented higher activity and significantly higher nocturnal behaviour related to escape or fear than was observed in the other groups. The groups control, RL and IR exhibited similar levels of nocturnal locomotor activity and nocturnal behaviour related to escape or fear. Plasma melatonin, at mid-dark was not significantly different between the control and groups RL and IR, while melatonin was significantly lower in group RH compared to the control. The authors recommended low intensity red night illumination for the non-invasive study of nocturnal behaviour of Senegalese sole adults. PMID:23711567

Carazo, I; Norambuena, F; Oliveira, C; Sánchez-Vázquez, F J; Duncan, N J

2013-06-13

123

Different neural melatonin-target tissues are critical for encoding and retrieving day length information in Siberian hamsters.  

Science.gov (United States)

Siberian hamsters exhibit several seasonal rhythms in physiology and behaviour, including reproduction, energy balance, body mass, and pelage colouration. Unambiguous long- and short day lengths stimulate and inhibit reproduction, respectively. Whether gonadal growth or regression occurs in an intermediate day length (e.g. 14 h L : 10 h D; 14L), depends on whether the antecedent day lengths were shorter (10L) or longer (16L). Variations in day length are encoded by the duration of nocturnal pineal melatonin secretion, which is decoded at several neural melatonin target tissues to control testicular structure and function. We assessed participation of three such structures in the acquisition and retrieval of day length information. Elimination of melatonin signalling to the nucleus reuniens (NRe), but not to the suprachiasmatic nucleus (SCN) or paraventricular thalamus (PVt), interfered with the acquisition of a long day reproductive response, whereas the obscuring of melatonin signals to the SCN and the NRe, but not to the PVt, interfered with the photoperiod history response. The SCN and NRe contribute in different ways to the melatonin-based system that mediates seasonal rhythms in male reproduction. PMID:17214872

Teubner, B J W; Freeman, D A

2007-02-01

124

Dopamine D2 receptor as a cellular component controlling nocturnal hyperactivities in Drosophila melanogaster.  

Science.gov (United States)

Dysfunctional regulation of brain dopamine (DA) functions has been found in patients with drug addiction and various neurological disorders that frequently accompany disturbance in sleep behavior. In this study, the roles of the dopaminergic nervous system on the regulation of daily locomotor activity rhythm were investigated in Drosophila melanogaster. Reduced synaptic DA release by expressing tetanus toxin gradually attenuated peak activity levels by altering activity patterns, particularly under constant darkness. Besides, flies with a mutant dopamine transporter fumin (fmn), in which the synaptic DA levels were elevated, displayed increased activities in both daytime and nighttime, but did more so at nighttime, suggesting that DA function is involved in regulation of fruit fly's nocturnal locomotor activities. Furthermore, flies treated with bromocriptine, an agonist of Drosophila dopamine D2 receptor (dD2R), exhibited nocturnal locomotor hyperactivity in a dose-dependent manner and this effect was inhibited in dD2R knockdown flies. When mutant flies null for period (per), timeless (tim), dClock (dClk), or cycle (cyc) were treated with bromocriptine, only cycle-null flies (cyc(01)) did not show induced nocturnal hyperactivities, suggesting that cyc might play a role in bromocriptine-induced nocturnal hyperactivities. Elevation of experimental temperature also increased nocturnal activities at the expense of daytime activities. The heat-induced increase in nocturnal activities gradually returned to basal levels at continuously elevated temperature. Inhibition of DA synthesis did not suppress heat-induced early development of nocturnal hyperactivity but prevented gradual decrement of initially elevated nocturnal activities, suggesting that DA impinges on certain adaptive roles in response to changes in environmental temperature. These results overall suggest that controlling dopaminergic transmission is important for daily locomotor behavior and bromocriptine-induced nocturnal hyperactivity which is mediated through dD2R receptor and CYC functions. In parallel to these results, excessive activation of dopaminergic neurotransmission, the primary cause of schizophrenia, is associated with abnormally elevated nocturnal locomotor activities through D2-type receptor in Drosophila. The results suggest that fruit flies are an excellent model system to provide some answers to previously unexplainable observations regarding the compromised dopaminergic nervous system and the related therapeutic agents. PMID:23286280

Lee, Gyunghee; Kikuno, Keiko; Bahn, Jae-Hoon; Kim, Kyeong-Man; Park, Jae H

2013-05-01

125

Melatonin, immune function and aging  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Aging is associated with a decline in immune function (immunosenescence, a situation known to correlate with increased incidence of cancer, infectious and degenerative diseases. Innate, cellular and humoral immunity all exhibit increased deterioration with age. A decrease in functional competence of individual natural killer (NK cells is found with advancing age. Macrophages and granulocytes show functional decline in aging as evidenced by their diminished phagocytic activity and impairment of superoxide generation. There is also marked shift in cytokine profile as age advances, e.g., CD3+ and CD4+ cells decline in number whereas CD8+ cells increase in elderly individuals. A decline in organ specific antibodies occurs causing reduced humoral responsiveness. Circulating melatonin decreases with age and in recent years much interest has been focused on its immunomodulatory effect. Melatonin stimulates the production of progenitor cells for granulocytes-macrophages. It also stimulates the production of NK cells and CD4+ cells and inhibits CD8+ cells. The production and release of various cytokines from NK cells and T-helper lymphocytes also are enhanced by melatonin. Melatonin presumably regulates immune function by acting on the immune-opioid network, by affecting G protein-cAMP signal pathway and by regulating intracellular glutathione levels. Melatonin has the potential therapeutic value to enhance immune function in aged individuals and in patients in an immunocompromised state.

Perumal SR Pandi

2005-11-01

126

Radioimmunoassay for melatonin in human serum  

International Nuclear Information System (INIS)

Goat antisera raised against N-acetyl-5-methoxytryptophan conjugated to bovine thyroglobulin by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide is utilized in a radioimmunoassay for melatonin. The raised antibodies are coupled to Sepharose 4B and melatonin in human serum is isolated by affinity chromatography, thereby avoiding the time-consuming extractions by organic solvents. A detection limit of 1.9 pg (8.2x10-15 mol)melatonin is achieved. The antibody specificity has been analysed and none of the common melatonin analogues influence this method of melatonin measurement. (Auth.)

127

Mitochondrial and Metabolic Dysfunction in Renal Convoluted Tubules of Obese Mice: Protective Role of Melatonin  

Science.gov (United States)

Obesity is a common and complex health problem, which impacts crucial organs; it is also considered an independent risk factor for chronic kidney disease. Few studies have analyzed the consequence of obesity in the renal proximal convoluted tubules, which are the major tubules involved in reabsorptive processes. For optimal performance of the kidney, energy is primarily provided by mitochondria. Melatonin, an indoleamine and antioxidant, has been identified in mitochondria, and there is considerable evidence regarding its essential role in the prevention of oxidative mitochondrial damage. In this study we evaluated the mechanism(s) of mitochondrial alterations in an animal model of obesity (ob/ob mice) and describe the beneficial effects of melatonin treatment on mitochondrial morphology and dynamics as influenced by mitofusin-2 and the intrinsic apoptotic cascade. Melatonin dissolved in 1% ethanol was added to the drinking water from postnatal week 5–13; the calculated dose of melatonin intake was 100 mg/kg body weight/day. Compared to control mice, obesity-related morphological alterations were apparent in the proximal tubules which contained round mitochondria with irregular, short cristae and cells with elevated apoptotic index. Melatonin supplementation in obese mice changed mitochondria shape and cristae organization of proximal tubules, enhanced mitofusin-2 expression, which in turn modulated the progression of the mitochondria-driven intrinsic apoptotic pathway. These changes possibly aid in reducing renal failure. The melatonin-mediated changes indicate its potential protective use against renal morphological damage and dysfunction associated with obesity and metabolic disease. PMID:25347680

Giugno, Lorena; Lavazza, Antonio; Reiter, Russel J.; Rodella, Luigi Fabrizio; Rezzani, Rita

2014-01-01

128

Intracoronary and systemic melatonin to patients with acute myocardial infarction : protocol for the IMPACT trial  

DEFF Research Database (Denmark)

INTRODUCTION: Ischaemia-reperfusion injury following acute myocardial infarctions (AMI) is an unavoidable consequence of the primary percutaneous coronary intervention (pPCI) procedure. A pivotal mechanism in ischaemia-reperfusion injury is the production of reactive oxygen species following reperfusion. The endogenous hormone, melatonin, works as an antioxidant and could potentially minimise the ischaemia-reperfusion injury. Given intracoronarily, it enables melatonin to work directly at the site of reperfusion. We wish to test if melatonin, as an antioxidant, can minimise the reperfusion injury following pPCI in patients with AMI. MATERIAL AND METHODS: The IMPACT trial is a multicentre, randomised, double-blinded, placebo-controlled study. We wish to include 2 × 20 patients with ST-elevation myocardial infarctions undergoing pPCI within six hours from symptom onset. The primary end-point is the Myocardial Salvage Index assessed by cardiovascular magnetic resonance imaging on day 4 (± 1) after pPCI. The secondary end-points are high-sensitivity troponin, creatinekinase myocardial band and clinical events. CONCLUSION: The aim of the IMPACT trial is to evaluate the effect of melatonin on reperfusion injuries following pPCI. Owing to its relatively non-toxic profile, melatonin is an easily implementable drug in the clinical setting, and melatonin has the potential to reduce morbidity in patients with AMI. FUNDING: This study received no financial support from the industry. TRIAL REGISTRATION: www.clinicaltrials.gov, clinical trials identifier: NCT01172171.

Halladin, Natalie L; Busch, Sarah EkelØf

2014-01-01

129

Extrapineal melatonin: sources, regulation, and potential functions.  

Science.gov (United States)

Endogenous melatonin is synthesized from tryptophan via 5-hydroxytryptamine. It is considered an indoleamine from a biochemical point of view because the melatonin molecule contains a substituted indolic ring with an amino group. The circadian production of melatonin by the pineal gland explains its chronobiotic influence on organismal activity, including the endocrine and non-endocrine rhythms. Other functions of melatonin, including its antioxidant and anti-inflammatory properties, its genomic effects, and its capacity to modulate mitochondrial homeostasis, are linked to the redox status of cells and tissues. With the aid of specific melatonin antibodies, the presence of melatonin has been detected in multiple extrapineal tissues including the brain, retina, lens, cochlea, Harderian gland, airway epithelium, skin, gastrointestinal tract, liver, kidney, thyroid, pancreas, thymus, spleen, immune system cells, carotid body, reproductive tract, and endothelial cells. In most of these tissues, the melatonin-synthesizing enzymes have been identified. Melatonin is present in essentially all biological fluids including cerebrospinal fluid, saliva, bile, synovial fluid, amniotic fluid, and breast milk. In several of these fluids, melatonin concentrations exceed those in the blood. The importance of the continual availability of melatonin at the cellular level is important for its physiological regulation of cell homeostasis, and may be relevant to its therapeutic applications. Because of this, it is essential to compile information related to its peripheral production and regulation of this ubiquitously acting indoleamine. Thus, this review emphasizes the presence of melatonin in extrapineal organs, tissues, and fluids of mammals including humans. PMID:24554058

Acuña-Castroviejo, Darío; Escames, Germaine; Venegas, Carmen; Díaz-Casado, María E; Lima-Cabello, Elena; López, Luis C; Rosales-Corral, Sergio; Tan, Dun-Xian; Reiter, Russel J

2014-08-01

130

Melatonin treatment protects against spinal cord injury induced functional and biochemical changes in rat urinary bladder.  

Science.gov (United States)

Oxidative stress induced by spinal cord injury (SCI) has deleterious effects on the function of several organ systems including the urinary bladder. In this study, we investigated the possible protective actions of melatonin on SCI-induced oxidative damage and urinary bladder dysfunction. Wistar albino rats (n = 24) were divided randomly as control, vehicle- or melatonin (10 mg/kg, ip)-treated SCI groups. To induce SCI, a standard weight-drop method that induced a moderately severe injury at T10 was used. Injured animals were given either vehicle or melatonin 15 min postinjury. One week postinjury, each rat was neurologically examined and then decapitated; blood samples were taken to evaluate neuron-specific enolase (NSE) and soluble protein 100? (S-100?). Spinal cord (SC) and urinary bladder samples were taken for functional studies and histological examination or stored for the measurement of malondialdehyde (MDA), glutathione (GSH) and nerve growth factor (NGF) levels and caspase-3 activity. Isometric contractions in bladder strips were induced by carbachol. In the SCI rats, decreased contractile responses of the bladder strips were found to be restored by melatonin treatment. Serum S-100? levels and NSE activities and tissue MDA levels and caspase-3 activities, all of which were elevated in the vehicle-treated SCI animals as compared to the control values, were reversed by melatonin treatment. On the other hand, reduced GSH and NGF levels due to SCI were restored by melatonin treatment. Furthermore, melatonin treatment improved histological findings. These findings suggest that melatonin reduces SCI-induced tissue injury and improves bladder functions through its effects on oxidative stress and NGF. PMID:22220508

Er?ahin, Mehmet; Özdemir, Zarife; Özsavc?, Derya; Akak?n, Dilek; Ye?en, Berrak Ç; Reiter, Russel J; Sener, Göksel

2012-04-01

131

Melatonin Inhibits GnRH-1, GnRH-3 and GnRH Receptor Expression in the Brain of the European Sea Bass, Dicentrarchus labrax.  

Science.gov (United States)

Several evidences supported the existence of melatonin effects on reproductive system in fish. In order to investigate whether melatonin is involved in the modulation of GnRH systems in the European sea bass, we have injected melatonin (0.5 µg/g body mass) in male specimens. The brain mRNA transcript levels of the three GnRH forms and the five GnRH receptors present in this species were determined by real time quantitative PCR. Our findings revealed day-night variations in the brain expression of GnRH-1, GnRH-3 and several GnRH receptors (dlGnRHR-II-1c, -2a), which exhibited higher transcript levels at mid-light compared to mid-dark phase of the photocycle. Moreover, an inhibitory effect of melatonin on the nocturnal expression of GnRH-1, GnRH-3, and GnRH receptors subtypes 1c, 2a and 2b was also demonstrated. Interestingly, the inhibitory effect of melatonin affected the expression of hypophysiotrophic GnRH forms and GnRH receptors that exhibit day-night fluctuations, suggesting that exogenous melatonin reinforce physiological mechanisms already established. These interactions between melatoninergic and GnRH systems could be mediating photoperiod effects on reproductive and other rhythmic physiological events in the European sea bass. PMID:23567273

Servili, Arianna; Herrera-Pérez, Patricia; Del Carmen Rendón, María; Muñoz-Cueto, José Antonio

2013-01-01

132

Melatonin Anticancer Effects: Review  

Directory of Open Access Journals (Sweden)

Full Text Available Melatonin (N-acetyl-5-methoxytryptamine, MLT, the main hormone produced by the pineal gland, not only regulates circadian rhythm, but also has antioxidant, anti-ageing and immunomodulatory properties. MLT plays an important role in blood composition, medullary dynamics, platelet genesis, vessel endothelia, and in platelet aggregation, leukocyte formula regulation and hemoglobin synthesis. Its significant atoxic, apoptotic, oncostatic, angiogenetic, differentiating and antiproliferative properties against all solid and liquid tumors have also been documented. Thanks, in fact, to its considerable functional versatility, MLT can exert both direct and indirect anticancer effects in factorial synergy with other differentiating, antiproliferative, immunomodulating and trophic molecules that form part of the anticancer treatment formulated by Luigi Di Bella (Di Bella Method, DBM: somatostatin, retinoids, ascorbic acid, vitamin D3, prolactin inhibitors, chondroitin-sulfate. The interaction between MLT and the DBM molecules counters the multiple processes that characterize the neoplastic phenotype (induction, promotion, progression and/or dissemination, tumoral mutation. All these particular characteristics suggest the use of MLT in oncological diseases.

Luigi Di Bella

2013-01-01

133

'Melatonin isomer' in wine is not an isomer of the melatonin but tryptophan-ethylester.  

Science.gov (United States)

Melatonin is a neurohormone, chronobiotic, and antioxidant compound found in wine and deriving directly from grapes and/or synthesized by yeast during alcoholic fermentation. In addition, a melatonin isomer has been detected in different foods, wine among them. The special interest for melatonin isomer related to the fact that it was found in greater quantities than melatonin and probably shares some of its biological properties. Despite this, its chemical structure has not yet been defined; although some researchers hypothesize, it could be melatonin with the ethylacetamide group shifted into position N1. Thus, the aim of our study was to identify the structures of the melatonin isomer. For this purpose, melatonin and melatonin isomer in Syrah wine were separated chromatographically by a sub-2 ?m particle column and detected by tandem mass spectrometry. The sample was then purified and concentrated by solid-phase extraction, hydrolyzed with alkali or esterase, and substrates and products quantified by UPLC-MS/MS. Moreover, melatonin, melatonin isomer, and their product ions were evaluated by high-resolution mass spectrometry. The amount of melatonin isomer and melatonin in the wine was 84 ± 4 and 3 ± 0 ng/mL, respectively. In the solutions, containing diluted alkali or esterase, melatonin isomer was hydrolyzed in about 8 min. Correspondingly, tryptophan was detected, and its amount increased and reached the maximum concentration in about 8 min. Melatonin concentration was not affected by diluted alkali or esterase. The fragmentation pattern of melatonin isomer was different from that of melatonin but comparable to that of tryptophan-ethylester. Finally, the so-called melatonin isomer identity was verified by cochromatography with authentic standard of tryptophan-ethylester. PMID:25251161

Gardana, Claudio; Iriti, Marcello; Stuknyt?, Milda; De Noni, Ivano; Simonetti, Paolo

2014-11-01

134

Bright light exposure during the daytime affects circadian rhythms of urinary melatonin and salivary immunoglobulin A.  

Science.gov (United States)

The effects of bright light exposure during the daytime on circadian urinary melatonin and salivary immunoglobulin A (IgA) rhythms were investigated in an environmental chamber controlled at a global temperature of 27 degrees C+/-0.2 degrees C and a relative humidity of 60%+/-5%. Seven diurnally active healthy females were studied twice, in bright and dim light conditions. Bright light of 5000 lux was provided by placing fluorescent lamps about 1 meter in front of the subjects during the daytime exposure (06:30-19:30) from 06:30 on day 1 to 10:30 on day 3. Dim light was controlled at 200 lux, and the subjects were allowed to sleep from 22:30 to 06:30 under both light exposure conditions. Urine and saliva were collected at 4h intervals for assessing melatonin and IgA. Melatonin excretion in the urine was significantly greater during the nighttime (i.e., at 06:30 on day 1 and at 02:30 on day 2) after the bright light condition than during the dim light condition. Furthermore, the concentration and the amount of salivary IgA tended to be higher in the bright light than in the dim light condition, especially during the night-time. Also, salivary IgA concentration and the total amount secreted in the saliva were significantly positively correlated with urinary melatonin. These results are consistent with the hypothesis that bright light exposure during the daytime enhances the nocturnal melatonin increase and activates the mucosal immune response. PMID:10373104

Park, S J; Tokura, H

1999-05-01

135

Effect of indomethacin on desmopressin resistant nocturnal polyuria and nocturnal enuresis  

DEFF Research Database (Denmark)

We evaluated the acute effect of indomethacin on renal water and solute handling in children with coexisting monosymptomatic nocturnal enuresis and desmopressin resistant nocturnal polyuria, and in healthy controls.

Kamperis, Konstantinos; Rittig, SØren

2012-01-01

136

Chronic melatonin treatment and its precursor L-tryptophan improve the monoaminergic neurotransmission and related behavior in the aged rat brain.  

Science.gov (United States)

Melatonin has an important role in the aging process as a potential drug to relieve oxidative damage, a likely cause of age-associated brain dysfunction. As age advances, the nocturnal production of melatonin decreases potentially causing physiological alterations. The present experiments were performed to study in vivo the effects of exogenously administered melatonin chronically on monoaminergic central neurotransmitters serotonin (5-HT), dopamine (DA) and norepinephrine (NE) and behavioral tests in old rats. The accumulation of 5-hydroxy-tryptophan (5-HTP) and L-3,4-dihydroxyphenylalanine (DOPA) after decarboxylase inhibition was used as a measure of the rate of tryptophan and tyrosine hydroxylation in rat brain. Also neurotransmitters 5-HT, DA and NE and some metabolites were quantified by HPLC. In control rats, an age-related decline was observed in neurochemical parameters. However, chronic administration of melatonin (1 mg/kg/day, diluted in drinking water, 4 wk) significantly reversed the age-induced deficits in all the monoaminergic neurotransmitters studied. Also, neurochemical parameters were analyzed after administration of melatonin biosynthesis precursor L-tryptophan (240 mg/kg/day, i.p., at night for 4 wk) revealing similar improvement effects to those induced by melatonin. Behavioral data corresponded well with the neurochemical findings since spatial memory test in radial-maze and motor coordination in rota-rod were significantly improved after chronic melatonin treatment. In conclusion, these in vivo findings suggest that melatonin and L-tryptophan treatments exert a long-term effect on the 5-HT, DA and NE neurotransmission by enhancing monoamine synthesis in aged rats, which might improve the age-dependent deficits in cognition and motor coordination. PMID:20082664

Esteban, Susana; Garau, Celia; Aparicio, Sara; Moranta, David; Barceló, Pere; Fiol, Maria Antonia; Rial, Rubén

2010-03-01

137

Chronobiology of Melatonin beyond the Feedback to the Suprachiasmatic Nucleus—Consequences to Melatonin Dysfunction  

Directory of Open Access Journals (Sweden)

Full Text Available The mammalian circadian system is composed of numerous oscillators, which gradually differ with regard to their dependence on the pacemaker, the suprachiasmatic nucleus (SCN. Actions of melatonin on extra-SCN oscillators represent an emerging field. Melatonin receptors are widely expressed in numerous peripheral and central nervous tissues. Therefore, the circadian rhythm of circulating, pineal-derived melatonin can have profound consequences for the temporal organization of almost all organs, without necessarily involving the melatonin feedback to the suprachiasmatic nucleus. Experiments with melatonin-deficient mouse strains, pinealectomized animals and melatonin receptor knockouts, as well as phase-shifting experiments with explants, reveal a chronobiological role of melatonin in various tissues. In addition to directly steering melatonin-regulated gene expression, the pineal hormone is required for the rhythmic expression of circadian oscillator genes in peripheral organs and to enhance the coupling of parallel oscillators within the same tissue. It exerts additional effects by modulating the secretion of other hormones. The importance of melatonin for numerous organs is underlined by the association of various diseases with gene polymorphisms concerning melatonin receptors and the melatonin biosynthetic pathway. The possibilities and limits of melatonergic treatment are discussed with regard to reductions of melatonin during aging and in various diseases.

Rüdiger Hardeland

2013-03-01

138

Melatonin enhances adult rat hippocampal progenitor cell proliferation via ERK signaling pathway through melatonin receptor.  

Science.gov (United States)

Melatonin, a neurohormone secreted mainly by the pineal gland, has a variety of physiological functions and neuroprotective effects. Previous studies have shown that melatonin could stimulate the proliferation of neural stem/progenitor cells (NS/PCs). Recent studies reported that the activities of mitogen-activated protein kinase (MAPK) of neural stem cells (NSCs) changed in response to the proliferative effect of melatonin. Therefore, the aim of the present study was to explore the proliferative mechanism mediated by melatonin on the adult rat hippocampal NS/PCs. Treatment with melatonin significantly increased the number of neurospheres in a concentration-dependent manner and up-regulated nestin protein. Pretreatment with luzindole, a melatonin receptor antagonist, and PD98059, a mitogen-activated protein kinase kinase (MEK) inhibitor, prevented the increase in the number of neurospheres formed by the activation of melatonin. The levels of phospho-c-Raf and phospho-extracellular signal-regulated kinase 1/2 (ERK1/2) increased when treated with melatonin. Pretreatment with luzindole or PD98059 prevented the melatonin-induced increase in these signaling molecules. The present results showed that melatonin could induce NS/PCs to proliferate by increasing phosphorylation of ERK1/2 and c-Raf through melatonin receptor. These results provide further evidence for a role of melatonin in promoting neurogenesis, adding to the remarkably pleiotropic nature of this neurohormone. This intrinsic modulator deserves further investigation to better understand its physiological and therapeutic implication. PMID:24956284

Tocharus, C; Puriboriboon, Y; Junmanee, T; Tocharus, J; Ekthuwapranee, K; Govitrapong, P

2014-09-01

139

The role of melatonin in radiation induced biochemical disturbances in brain and thyroid gland in adult male albino rats  

International Nuclear Information System (INIS)

Radiation induced changes in adult male albino male rats before and after melatonin administration were monitored to detect some biochemical changes in brain and thyroid gland. The parameters monitored were dopamine (DA), norepinephdne (NE) and gamma aminobutyric acid (GABA) in brain and triiodothyronine (T3) thyroxine (T4) and thyroid stimulating hormone (TSH) in serum of irradiated adult male albino rats before and after intraperitoneal injection of melatonin. Results indicated that 6.0 Gy whole body ?-irradiated rats showed gradual and significant decrease in DA, NE and GABA contents in different brain areas under investigation (cerebellum, pons+medulla oblongata, corpus striatum, cerebral cortex, hypothalamus, midbrain and hippocampus). The maximum effect of whole body ?-irradiation was observed after 21 days. Moreover, gradual and significant decrease in serum T3 and T4 levels were recorded after ?-irradiation. However, TSH level showed significant elevation throughout the experimental period. Melatonin at a dose level of 15 mg/kg b.wt. was intraperitoneally injected daily 30 minutes after 6.0 Gy whole body ?-irradiation, ameliorated DA, NE and GABA contents in different brain areas compared to those measured in irradiated rats. Moreover, melatonin gradually attenuated the effect of ?-irradiation on serum T3 and T4 levels to reach nearly the control level at day 21 after melatonin injection. However, melatonin ameliorated the elevated TSH level induced by ?-irradiation to reach its corresponding control value at day 21

140

The Impact of Melatonin on Glucose Homeostasis  

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Full Text Available Objective: Melatonin is a pineal product mainly charged with the maintenance of antioxidant conditions in human. This study is performed to identify the short-term effect of melatonin on glucose homeostasis in diabetic patients. Materials and Methods: Melatonin and placebo were given perorally to sixty patients. Blood glucose and insulin levels were measured with constant intervals. Results: No significant correlation was found among the levels of glucose, insulin and HOMA-IR index at any time after melatonin/placebo administration.Conclusions: Prospective studies with long-term use of melatonin are needed to define the exact role of melatonin in glucose homeostasis. Turk Jem 2009; 13: 52-5

Zeynep Arzu Ye?in

2009-12-01

 
 
 
 
141

Effectiveness of Melatonin, as a Radiation Damage-Mitigating Drug in Modulating Liver Biochemical disorders in ?-Irradiated Rats  

International Nuclear Information System (INIS)

Melatonin has an anti per oxidative effect on several tissues as well as a scavenger effect on reactive oxygen species (ROS). Whilst radiation-hazards due to free radical generation, present enormous challenges for biological and medical safety. Therefore, rats were classified into four groups; control (n= 8), (received 0.5 ml of alcoholic saline as a vehicle for 5 days). Melatonin-treated rats received 10 mg/ kg body wt, for 5 days (given to the animals in the morning via stomach tube). gamma-irradiated rats received 0.5 ml of the melatonin vehicle followed by one shot dose of 3 Gy gamma-rays. Each of these groups was compared with a further group, which-received melatonin for 5 days after 3 Gy gamma-irradiation exposure. The results revealed that all considered biochemical parameters were not changed significantly in melatonin-treated group as compared with control one. In the liver tissue of the gamma-irradiated animals (3 Gy), the oxidative stress markers malondialdehyde (MDA) and protein carbonyl (PC) were significantly increased, while a marked decrease occurred in the contents of deoxy- and ribo-nucleic acids (DNA and RNA) and glutathione (GSH) as well as activity of glutathione-S-transferase (GST). In addition, catalase (CAT) and myeloperoxidase (MPO) activities were increased. Activities of aspartate transaminase (AST), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT) were significantly increased in sera of the irradiated rats. Treatment with melatonin for 5 days after gamma-rays exposure significantly modulated the radiation-induced elevations in MDA and PC levels in the liver tissue and significantly restored hepatic GSH content, GST, CAT and MPO activities. Post-irradiation treatment with melatonin showed significant higher hepatic DNA and RNA contents than irradiated rats. The activities of AST, ALP, and GGT in serum were significantly ameliorated when melatonin was administrated after irradiation. Conclusion: Melatonin has effective mitigating effects against gamma- radiation induced oxidative stress and liver injury.

142

Melatonin Improves Mitochondrial Function by Promoting MT1/SIRT1/PGC-1 Alpha-Dependent Mitochondrial Biogenesis in Cadmium-Induced Hepatotoxicity In Vitro.  

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Melatonin is an indolamine synthesized in the pineal gland that has a wide range of physiological functions, and it has been under clinical investigation for expanded applications. Increasing evidence demonstrates that melatonin can ameliorate cadmium-induced hepatotoxicity. However, the potentially protective effects of melatonin against cadmium-induced hepatotoxicity and the underlying mechanisms of this protection remain unclear. This study investigates the protective effects of melatonin pretreatment on cadmium-induced hepatotoxicity and elucidates the potential mechanism of melatonin-mediated protection. We exposed HepG2 cells to different concentrations of cadmium chloride (2.5, 5, and 10?M) for 12 h. We found that Cd stimulated cytotoxicity, disrupted the mitochondrial membrane potential, increased reactive oxygen species production, and decreased mitochondrial mass and mitochondrial DNA content. Consistent with this finding, Cd exposure was associated with decreased Sirtuin 1 (SIRT1) protein expression and activity, thus promoted acetylation of PGC-1 alpha, a key enzyme involved in mitochondrial biogenesis and function, although Cd did not disrupt the interaction between SIRT1 and PGC-1 alpha. However, all cadmium-induced mitochondrial oxidative injuries were efficiently attenuated by melatonin pretreatment. Moreover, Sirtinol and SIRT1 siRNA each blocked the melatonin-mediated elevation in mitochondrial function by inhibiting SIRT1/ PGC-1 alpha signaling. Luzindole, a melatonin receptor antagonist, was found to partially block the ability of melatonin to promote SIRT1/ PGC-1 alpha signaling. In summary, our results indicate that SIRT1 plays an essential role in the ability of moderate melatonin to stimulate PGC-1 alpha and improve mitochondrial biogenesis and function at least partially through melatonin receptors in cadmium-induced hepatotoxicity. PMID:25159133

Guo, Pan; Pi, Huifeng; Xu, Shangcheng; Zhang, Lei; Li, Yuming; Li, Min; Cao, Zhengwang; Tian, Li; Xie, Jia; Li, Renyan; He, Mindi; Lu, Yonghui; Liu, Chuan; Duan, Weixia; Yu, Zhengping; Zhou, Zhou

2014-11-01

143

The Impact of Melatonin on Glucose Homeostasis  

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Objective: Melatonin is a pineal product mainly charged with the maintenance of antioxidant conditions in human. This study is performed to identify the short-term effect of melatonin on glucose homeostasis in diabetic patients. Materials and Methods: Melatonin and placebo were given perorally to sixty patients. Blood glucose and insulin levels were measured with constant intervals. Results: No significant correlation was found among the levels of glucose, insulin and HOMA-IR index at any ti...

Zeynep Arzu Ye?in; Rüya Mutluay; ?ehri Elbeg; Resul Karaku?; Nuri Çak?r

2009-01-01

144

Evaluation of functional integrity of the retinohypothalamic tract in advanced glaucoma using multifocal electroretinography and light-induced melatonin suppression.  

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The aim of the study was to investigate the survival of melanopsin-expressing retinal ganglion cells (mRGCs) and the functional integrity of the retinohypothalamic tract in patients with bilateral advanced glaucomatous optic neuropathy by measuring the neuroendocrine light response of the pineal gland. Nine patients with bilateral advanced primary open-angle glaucoma (glaucoma group) and nine normal control subjects (control group) were included in this pilot observational, prospective, case-control study. The best-corrected visual acuity logMAR, standard automated perimetry mean deviation, and the retinal nerve fiber layer thickness determined by optical coherence tomography and multifocal electroretinography were used to evaluate the changes. Melatonin was analyzed in the saliva by radioimmunoassay before and after exposure to bright light (600 lux) for 60 min at night. The advanced glaucoma group did not have any significant nocturnal melatonin suppression after exposure to bright light (14.28 ± 3.07 pg/ml pre-light melatonin concentration vs. 15.22 ± 3.56 pg/ml after light exposure; p = 0.798) unlike the marked melatonin suppression in the control group (22.43 ± 4.37 pg/ml pre-light melatonin concentration vs. 11.25 ± 1.89 pg/ml after light exposure; p < 0.002). Response density estimates by the scalar product amplitude measure for the interval 0-80 ms of the first-order kernel responses were similar in both groups, indicating that outer retinal function was significantly unchanged in the glaucoma group (5.95 ± 0.54 nV/dg^2) compared with the control group (6.20 ± 0.22 nV/dg^2) (p = 0.689). Our findings are consistent with the interpretation that the rhythmic secretion of melatonin was affected in advanced glaucoma, suggesting that attention should be paid to non-image-forming visual functions, such as control of circadian rhythm and the clinical impact in patients with glaucoma. PMID:20692255

Pérez-Rico, Consuelo; de la Villa, Pedro; Arribas-Gómez, Ignacio; Blanco, Román

2010-11-01

145

Melatonin modulation of presynaptic nicotinic acetylcholine receptors located on short noradrenergic neurons of the rat vas deferens: a pharmacological characterization  

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Full Text Available Melatonin, the pineal hormone produced during the dark phase of the light-dark cycle, modulates neuronal acetylcholine receptors located presynaptically on nerve terminals of the rat vas deferens. Recently we showed the presence of high affinity nicotine-binding sites during the light phase, and low and high affinity binding sites during the dark phase. The appearance of the low affinity binding sites was due to the nocturnal melatonin surge and could be mimicked by exposure to melatonin in vitro. The aim of the present research was to identify the receptor subtypes responsible for the functional response during the light and the dark phase. The rank order of potency of agonists was dimethylphenylpiperazinium (DMPP = cytisine > nicotine > carbachol and DMPP = nicotine = cytisine > carbachol, during the light and dark phase, respectively, due to an increase in apparent affinity for nicotine. Mecamylamine similarly blocked the DMPP response during the light and the dark phase, while the response to nicotine was more efficiently blocked during the light phase. In contrast, methyllycaconitine inhibited the nicotine-induced response only at 21:00 h. Since a7 nicotinic acetylcholine receptors (nAChRs have low affinity for nicotine in binding assays, we suggest that a mixed population composed of a3ß4 - plus a7-bearing nAChR subtypes is present at night. This plasticity in receptor subtypes is probably driven by melatonin since nicotine-induced contraction in organs from animals sacrificed at 15:00 h and incubated with melatonin (100 pg/ml, 4 h is not totally blocked by mecamylamine. Thus melatonin, by acting directly on the short adrenergic neurons that innervate the rat vas deferens, induces the appearance of the low affinity binding site, probably an a7 nAChR subtype.

Zago W.M.

1999-01-01

146

Melatonin modulation of presynaptic nicotinic acetylcholine receptors located on short noradrenergic neurons of the rat vas deferens: a pharmacological characterization  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Melatonin, the pineal hormone produced during the dark phase of the light-dark cycle, modulates neuronal acetylcholine receptors located presynaptically on nerve terminals of the rat vas deferens. Recently we showed the presence of high affinity nicotine-binding sites during the light phase, and low [...] and high affinity binding sites during the dark phase. The appearance of the low affinity binding sites was due to the nocturnal melatonin surge and could be mimicked by exposure to melatonin in vitro. The aim of the present research was to identify the receptor subtypes responsible for the functional response during the light and the dark phase. The rank order of potency of agonists was dimethylphenylpiperazinium (DMPP) = cytisine > nicotine > carbachol and DMPP = nicotine = cytisine > carbachol, during the light and dark phase, respectively, due to an increase in apparent affinity for nicotine. Mecamylamine similarly blocked the DMPP response during the light and the dark phase, while the response to nicotine was more efficiently blocked during the light phase. In contrast, methyllycaconitine inhibited the nicotine-induced response only at 21:00 h. Since a7 nicotinic acetylcholine receptors (nAChRs) have low affinity for nicotine in binding assays, we suggest that a mixed population composed of a3ß4 - plus a7-bearing nAChR subtypes is present at night. This plasticity in receptor subtypes is probably driven by melatonin since nicotine-induced contraction in organs from animals sacrificed at 15:00 h and incubated with melatonin (100 pg/ml, 4 h) is not totally blocked by mecamylamine. Thus melatonin, by acting directly on the short adrenergic neurons that innervate the rat vas deferens, induces the appearance of the low affinity binding site, probably an a7 nAChR subtype.

W.M., Zago; R.P., Markus.

147

Melatonin receptors: Current status, facts, and hypothesis  

International Nuclear Information System (INIS)

Great progress has been made in the identification of melatonin binding sites, commonly identified as melatonin receptors by many authors, in recent years. The bulk of these studies have investigated the sites using either autoradiographic and biochemical techniques with the majority of the experiments being done on the rat, Djungarian and Syrian hamster, and sheep, although human tissue has also been employed. Many of the studies have identified melatonin binding in the central nervous system with either tritium- or iodine-labelled ligands. The latter ligand seems to provide the most reproducible and consistent data. Of the central neural tissues examined, the suprachiasmatic nuclei are most frequently mentioned as a location for melatonin binding sites although binding seems to be widespread in the brain. The other tissue that has been prominently mentioned as a site for melatonin binding is the pars tuberalis of the anterior pituitary gland. There may be time-dependent variations in melatonin binding densities in both neural and pituitary gland tissue. Very few attempts have been made to identify melatonin binding outside of the central nervous system despite the widespread actions of melatonin. Preliminary experiments have been carried out on the intracellular second messengers which mediate the actions of melatonin

148

Plasma melatonin is reduced in Huntington's disease.  

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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. Onset of melatonin rise was significantly more temporally spread in both premanifest and stage II/III Huntington's disease subjects compared with controls. A nonsignificant trend also was seen for reduced pulsatile secretion of melatonin. Melatonin concentrations are reduced in Huntington's disease. Altered melatonin patterns may provide an explanation for disrupted sleep and circadian behavior in Huntington's disease, and represent a biomarker for disease state. Melatonin therapy may help the sleep disorders seen in Huntington's disease. © 2014 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society. PMID:25164424

Kalliolia, Eirini; Silajdži?, Edina; Nambron, Rajasree; Hill, Nathan R; Doshi, Anisha; Frost, Chris; Watt, Hilary; Hindmarsh, Peter; Björkqvist, Maria; Warner, Thomas T

2014-10-01

149

Does melatonin have therapeutic use in tinnitus?  

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Melatonin, a hormone produced by the pineal gland, may be a promising treatment option for tinnitus. The primary functions of this hormone are believed to be the initiation and maintenance of sleep because its secretions coincide with circadian rhythms. Some investigators have noted that melatonin may alleviate subjective symptoms of tinnitus. Moreover, melatonin may have properties protective against ototoxic drugs such as amikacin, gentamicin, or cancer therapeutic agents that are dose dependent. In vitro, melatonin has demonstrated antioxidative properties and it has been postulated that these antioxidative properties contribute to the alleviation of tinnitus. Melatonin levels used to obtain these findings in vitro, however, are at supraphysiologic levels; therefore, it is more likely that the benefits from taking supplemental melatonin occur from minimal antioxidative properties, sleep enhancement, or other potential methods of action that are not yet understood. Melatonin offers minimal risk of toxicity with modest daily doses such as 1 to 3 mg, as well as a low cost and favorable adverse effect profile for older adults. In addition to potential benefits in the treatment of tinnitus, melatonin also may have beneficial neurogenerative properties. We recommend that melatonin be considered for use in patients with significant tinnitus. PMID:24945170

Merrick, Leah; Youssef, Dima; Tanner, Michelle; Peiris, Alan N

2014-06-01

150

Melatonin reduces phosphine-induced lipid and DNA oxidation in vitro and in vivo in rat brain.  

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Phosphine (PH(3)), a widely used pesticide, was found in our recent study to induce oxidative damage in the brain, liver and lung of rats. We also observed that melatonin significantly blocked this action. The present study focused on brain and the magnitude and mechanism of protection of PH(3)-induced oxidative damage by melatonin in vitro and in vivo. PH(3) in whole brain homogenate (3 mg protein/mL Tris-HCl pH 7.4 buffer) induced increasing lipid peroxidation [as malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA)] dependent on concentration (0.25-2 mM) and time (30-150 min), reaching a maximum level of 2.9-fold at 90 min after PH(3) at 1 mM. Elevation of MDA + 4-HDA levels by PH(3) at 1 mM was also observed in homogenates of cerebral cortex, cerebellum, hippocampus and hypothalamus examined individually. Melatonin at 0.1-2 mM progressively inhibited PH(3)-induced lipid peroxidation in brain and regions thereof. Additionally, PH(3) induced brain DNA oxidation in vitro and in vivo determined as 8-hydroxyguanosine (8-OH-dG). Melatonin at 1 mM significantly suppressed PH(3)-induced brain DNA oxidation in vitro. PH(3) at 4 mg/kg i.p. significantly elevated 8-OH-dG in frontal cortex and melatonin prevented it. PH(3) in vivo marginally lowered brain glutathione peroxidase activity and melatonin restored it completely. In contrast, PH(3) and melatonin both stimulated superoxide dismutase production. Brain glutathione (GSH) levels in PH(3)-treated rats were significantly reduced at 30 min and recovered gradually. It is concluded that melatonin, probably because of its free radical scavenging ability, confers marked protection against PH(3)-induced oxidative toxicity in brain. PMID:11841601

Hsu, Ching-Hung; Chi, Bei-Ching; Casida, John E

2002-01-01

151

Melatonin Attenuates Intermittent Hypoxia-Induced Lipid Peroxidation and Local Inflammation in Rat Adrenal Medulla  

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Full Text Available Chronic intermittent hypoxia (CIH induces lipid peroxidation and leads to cardiovascular dysfunction, in which impaired activities of the adrenal medulla are involved. This may be caused by CIH-induced injury in the adrenal medulla, for which the mechanism is currently undefined. We tested the hypothesis that melatonin ameliorates the CIH-induced lipid peroxidation, local inflammation and cellular injury in rat adrenal medulla. Adult Sprague–Dawley rats were exposed to air (normoxic control or hypoxia mimicking a severe recurrent sleep apnoeic condition for 14 days. The injection of melatonin (10 mg/kg or vehicle was given before the daily hypoxic treatment. We found that levels of malondialdehyde and nitrotyrosine were significantly increased in the vehicle-treated hypoxic group, when compared with the normoxic control or hypoxic group treated with melatonin. Also, the protein levels of antioxidant enzymes (superoxide dismutase (SOD-1 and SOD-2 were significantly lowered in the hypoxic group treated with vehicle but not in the melatonin group. In addition, the level of macrophage infiltration and the expression of inflammatory cytokines (tumor necrosis factor (TNF-?, interleukin (IL-1? and IL-6 and mediators (inducible nitric oxide synthase (iNOS, cyclooxygenase-2 (COX-2 were elevated in the vehicle-treated hypoxic group, but were significantly ameliorated by the melatonin treatment. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. In conclusion, CIH-induced lipid peroxidation causes local inflammation and cellular injury in the adrenal medulla. The antioxidant and anti-inflammatory actions of melatonin are indicative of a protective agent against adrenal damage in patients with severe obstructive sleep apnea syndrome.

Yu Liu

2014-10-01

152

Melatonin attenuates intermittent hypoxia-induced lipid peroxidation and local inflammation in rat adrenal medulla.  

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Chronic intermittent hypoxia (CIH) induces lipid peroxidation and leads to cardiovascular dysfunction, in which impaired activities of the adrenal medulla are involved. This may be caused by CIH-induced injury in the adrenal medulla, for which the mechanism is currently undefined. We tested the hypothesis that melatonin ameliorates the CIH-induced lipid peroxidation, local inflammation and cellular injury in rat adrenal medulla. Adult Sprague-Dawley rats were exposed to air (normoxic control) or hypoxia mimicking a severe recurrent sleep apnoeic condition for 14 days. The injection of melatonin (10 mg/kg) or vehicle was given before the daily hypoxic treatment. We found that levels of malondialdehyde and nitrotyrosine were significantly increased in the vehicle-treated hypoxic group, when compared with the normoxic control or hypoxic group treated with melatonin. Also, the protein levels of antioxidant enzymes (superoxide dismutase (SOD)-1 and SOD-2) were significantly lowered in the hypoxic group treated with vehicle but not in the melatonin group. In addition, the level of macrophage infiltration and the expression of inflammatory cytokines (tumor necrosis factor (TNF)-?, interleukin (IL)-1? and IL-6) and mediators (inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2)) were elevated in the vehicle-treated hypoxic group, but were significantly ameliorated by the melatonin treatment. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. In conclusion, CIH-induced lipid peroxidation causes local inflammation and cellular injury in the adrenal medulla. The antioxidant and anti-inflammatory actions of melatonin are indicative of a protective agent against adrenal damage in patients with severe obstructive sleep apnea syndrome. PMID:25314303

Yu, Liu; Lim, Tipoe George; Lung, Fung Man

2014-01-01

153

Homeobox genes and melatonin synthesis: regulatory roles of the cone-rod homeobox transcription factor in the rodent pineal gland.  

Science.gov (United States)

Nocturnal synthesis of melatonin in the pineal gland is controlled by a circadian rhythm in arylalkylamine N-acetyltransferase (AANAT) enzyme activity. In the rodent, Aanat gene expression displays a marked circadian rhythm; release of norepinephrine in the gland at night causes a cAMP-based induction of Aanat transcription. However, additional transcriptional control mechanisms exist. Homeobox genes, which are generally known to encode transcription factors controlling developmental processes, are also expressed in the mature rodent pineal gland. Among these, the cone-rod homeobox (CRX) transcription factor is believed to control pineal-specific Aanat expression. Based on recent advances in our understanding of Crx in the rodent pineal gland, we here suggest that homeobox genes play a role in adult pineal physiology both by ensuring pineal-specific Aanat expression and by facilitating cAMP response element-based circadian melatonin production. PMID:24877149

Rohde, Kristian; Møller, Morten; Rath, Martin Fredensborg

2014-01-01

154

Homeobox genes and melatonin synthesis : regulatory roles of the cone-rod homeobox transcription factor in the rodent pineal gland  

DEFF Research Database (Denmark)

Nocturnal synthesis of melatonin in the pineal gland is controlled by a circadian rhythm in arylalkylamine N-acetyltransferase (AANAT) enzyme activity. In the rodent, Aanat gene expression displays a marked circadian rhythm; release of norepinephrine in the gland at night causes a cAMP-based induction of Aanat transcription. However, additional transcriptional control mechanisms exist. Homeobox genes, which are generally known to encode transcription factors controlling developmental processes, are also expressed in the mature rodent pineal gland. Among these, the cone-rod homeobox (CRX) transcription factor is believed to control pineal-specific Aanat expression. Based on recent advances in our understanding of Crx in the rodent pineal gland, we here suggest that homeobox genes play a role in adult pineal physiology both by ensuring pineal-specific Aanat expression and by facilitating cAMP response element-based circadian melatonin production.

Rohde, Kristian; MØller, Morten

2014-01-01

155

Melatonin reduces glial reactivity in the hippocampus, cortex, and cerebellum of streptozotocin-induced diabetic rats.  

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Hyperglycemia plays a critical role in the development and progression of diabetic neuropathy. One of the mechanisms by which hyperglycemia causes neural degeneration is via the increased oxidative stress that accompanies diabetes. Metabolic and oxidative insults often cause rapid changes in glial cells. Key indicators of this response are increased synthesis of glial fibrillary acidic protein (GFAP) and S100B, both astrocytic markers. In the present study, we examined glial reactivity in hippocampus, cortex, and cerebellum of streptozotocin (STZ)-induced diabetic rats by determining the expression of GFAP and S-100B and we evaluated the effect of melatonin on the glial response. Western blot measurement of contents in brain regions after 6 weeks of STZ-induced diabetes indicated significant increases in these constituents compared with those in nondiabetic controls. Administration of melatonin prevented the upregulation of GFAP in all brain regions of diabetic rats. Using GFAP immunohistochemistry, we observed an increase in GFAP immunostaining in the hippocampus of STZ-diabetic rats relative to levels in the control brains. Treatment with melatonin resulted in an obvious reduction of GFAP-immunoreactive astrocytes in hippocampus. Like GFAP, S100B levels also were increased in all three brain areas of diabetic rats, an effect also reduced by melatonin treatment. Finally, the levels of lipid peroxidation products were elevated as a consequence of diabetes, with this change also being prevented by melatonin. These results suggest that diabetes causes increased glial reactivity possibly due to elevated oxidative stress, and administration of melatonin represents an achievable adjunct therapy for preventing gliosis. PMID:14583344

Baydas, Giyasettin; Reiter, Russel J; Yasar, Abdullah; Tuzcu, Mehmet; Akdemir, Ismail; Nedzvetskii, Viktor S

2003-10-01

156

Melatonin reduces the expression of chemokines in rat with trinitrobenzene sulfonic acid-induced colitis  

International Nuclear Information System (INIS)

Objective was to investigate the effect of melatonin on the colon inflammatory injury of rats with colitis and determine whether this effect is associated with inhibition of chemoattractant molecules interleukins (IL-8) and monocyte chemoattractant protein (MCP)-1.The study was designed and implemented in JingMen No.1 People's Hospital, HuBei Province, from May 2006 to April 2007. It involved 72 animals divided into 6 groups of 12 each: normal group, model group, 5-aminosalisalicylic acid group, and melatonin group (dose of 2.5, 5.0 and 10.0mg/kg). Rat colitis model was established by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) enema. Interleukin-8 and MCP-1 proteins in colon tissue were examined by immunohistochemistry and western blot. The messenger-RNA expressions of chemokines were determined by reverse transcription polymerase chain reaction analysis. Trinitrobenzene sulfonic acid enema resulted in pronounced pathological changes of colonic mucosa in model rats, which were in accordance with the significantly elevated Myeloperoxidase activity. Expressions of chemokines were up-regulated in colitis. Melatonin treatment reduced colonic lesions and improved colitis symptom, and decreased the protein and mRNA expressions of IL-8 and MCP-1 significantly in colon tissues of rats with colitis. Chemokines IL-8 and MCP-1 are elevated in mucosal tissues in colitis and play an important role in the perpetuation of tissue destructive inflammatory process; melatonin reduces e inflammatory process; melatonin reduces colonic inflammatory injury of rats colitis through down-regulating the expressions of chemokines. Melatonin can be considered as a novel therapeutic alternative for the treatment of inflammatory bowel disease. (author)

157

Concentração plasmática de melatonina em novilhas bubalinas (Bubalus bubalis) ao longo do ano / Plasma melatonin in bufallo heifers (Bubalus bubalis) during a year  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Coletaram-se nove amostras de sangue ao longo do dia, mês-a-mês durante um ano, de seis novilhas bubalinas da raça Mediterrâneo, para determinação da melatonina plasmática dos animais mantidos na latitude 22° Sul. A concentração plasmática de melatonina se elevou lentamente até atingir o pico entre [...] 21 e 23 horas, permanecendo elevada até as 3-5 horas. A seguir, a concentração diminuiu para valores baixos antes do nascer do sol. A duração da elevação noturna de melatonina plasmática não acompanhou a duração do período noturno ao longo do ano e a diminuição da concentração diurna de melatonina plasmática ocorreu na época de maior atividade reprodutiva estimada do rebanho. Abstract in english Nine blood samples were taken to determine plasma melatonin in a 24h-period/month for a year. The six buffalo heifers used were kept at latitude 22° South. Plasma melatonin rose slowly, peaking at night (between 9 and 11pm) and maintained until 3 to 5am. Melatonin concentration decreased day-time to [...] lower levels until sunrise. Nocturnal higher plasmatic melatonin did not vary with night length over the year. Diurnal melatonin concentrations were lower when estimated reproductive rate was the highest for the herd.

P.S.R., Mattos; R., Franzolin; K.O., Nonaka.

158

Melatonin-Based Therapeutics for Neuroprotection in Stroke  

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Full Text Available The present review paper supports the approach to deliver melatonin and to target melatonin receptors for neuroprotection in stroke. We discuss laboratory evidence demonstrating neuroprotective effects of exogenous melatonin treatment and transplantation of melatonin-secreting cells in stroke. In addition, we describe a novel mechanism of action underlying the therapeutic benefits of stem cell therapy in stroke, implicating the role of melatonin receptors. As we envision the clinical entry of melatonin-based therapeutics, we discuss translational experiments that warrant consideration to reveal an optimal melatonin treatment strategy that is safe and effective for human application.

Cesar V. Borlongan

2013-04-01

159

Melatonin in sperm biology: breaking paradigms.  

Science.gov (United States)

Melatonin is a ubiquitous molecule, present in a wide range of organisms, and involved in multiple functions. Melatonin relays the information about the photoperiod to the tissues that express melatonin-binding sites in both central and peripheral nervous systems. This hormone has a complex mechanism of action. It can cross the cell plasma membrane and exert its actions in all cells of the body. Certain melatonin actions are mediated by receptors that belong to the superfamily of G-protein-coupled receptors (GPCRs), the MT1 and MT2 membrane. Melatonin can also bind to calmodulin as well as to nuclear receptors of the retinoic acid receptor family, ROR?1, ROR?2 and RZR?. The purpose of this review is to report on recent developments in the physiological role of melatonin and its receptors. Specific issues concerning the biological function of melatonin in mammalian seasonal reproduction and spermatozoa are considered. The significance of the continuous presence of melatonin in seminal plasma with a fairly constant concentration is also discussed. PMID:25277428

Cebrián-Pérez, J A; Casao, A; González-Arto, M; dos Santos Hamilton, T R; Pérez-Pé, R; Muiño-Blanco, T

2014-10-01

160

Seasonal differences in melatonin concentrations and heart rates during sleep in obese subjects in Japan  

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During the past several decades, obesity has been increasing globally. In Japan, obesity is defined by a BMI of 25 kg/m2 or over; 28.6 % of men and 20.6 % of women are obese. Obese people have an increased incidence of developing cardiovascular, renal, and hormonal diseases and sleep disorders. Obese people also have shortened sleep durations. We investigated seasonal differences in melatonin concentrations, heart rates, and heart rate variability during sleep in obese subjects in Japan. Five obese (BMI, 32.0 ± 4.9 kg/m2) and five non-obese (BMI, 23.2 ± 2.9 kg/m2) men participated in this study in the summer and winter. Electrocardiograms were measured continuously overnight in a climatic chamber at 26 °C with a relative humidity of 50 %. Saliva samples for melatonin were collected at 2300 hours, 0200 hours, and 0600 hours. We found that melatonin concentrations during sleep in obese subjects were significantly lower than those in non-obese subjects in the winter. Heart rate during sleep in winter was significantly higher than that in summer in both obese and non-obese subjects. Heart rate variability was not significantly different in the summer and winter in both obese and non-obese subjects. Our results show that decreased nocturnal melatonin concentrations during winter in obese men may be related to higher heart rates, and this may suggest that obese men are at an increased risk of a cardiovascular incident during sleep, especially in the winter.

Sato, Maki; Kanikowska, Dominika; Iwase, Satoshi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Sato, Motohiko; Sugenoya, Junichi

2013-09-01

 
 
 
 
161

Melatonin attenuates hypoxic pulmonary hypertension by inhibiting the inflammation and the proliferation of pulmonary arterial smooth muscle cells.  

Science.gov (United States)

Hypoxia-induced inflammation and excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) play important roles in the pathological process of hypoxic pulmonary hypertension (HPH). Melatonin possesses anti-inflammatory and antiproliferative properties. However, the effect of melatonin on HPH remains unclear. In this study, adult Sprague-Dawley rats were exposed to intermittent chronic hypoxia for 4 wk to mimic a severe HPH condition. Hemodynamic and pulmonary pathomorphology data showed that chronic hypoxia significantly increased right ventricular systolic pressures (RVSP), weight of the right ventricle/left ventricle plus septum (RV/LV+S) ratio, and median width of pulmonary arterioles. Melatonin attenuated the elevation of RVSP, RV/LV+S, and mitigated the pulmonary vascular structure remodeling. Melatonin also suppressed the hypoxia-induced high expression of proliferating cell nuclear antigen (PCNA), hypoxia-inducible factor-1? (HIF-1?), and nuclear factor-?B (NF-?B). In vitro, melatonin concentration-dependently inhibited the proliferation of PASMCs and the levels of phosphorylation of Akt and extracellular signal-regulated kinases1/2 (ERK1/2) caused by hypoxia. These results suggested that melatonin might potentially prevent HPH via anti-inflammatory and antiproliferative mechanisms. PMID:25251287

Jin, Haifeng; Wang, Yueyue; Zhou, Lei; Liu, Lu; Zhang, Peng; Deng, Wuguo; Yuan, Yuhui

2014-11-01

162

The early response of pineal N-acetyltransferase activity, melatonin and catecholamine levels in rats irradiated with gamma rays  

International Nuclear Information System (INIS)

Male Wistar rats adapted to an artificial light-dark regimen were whole-body gamma-irradiated with a dose of 14.35 Gy. Irradiation, sham-irradiation and decapitation 30, 60 and 120 min after the exposure were performed between 2000 h and 0100 h in the darkness. The serotonin N-acetyltransferase activity (NAT), the concentration of melatonin and corticosterone were also determined. Ionizing radiation did not change the activity of NAT, the key enzyme of melatonin synthesis; however, it decreased the concentration of pineal melatonin. The concentration of pineal dopamine and norepinephrine decreased 30 and 120 min after exposure, while the concentration of epinephrine was elevated 30 min after irradiation, though later it was markedly decreased. The serum melatonin level was not changed but an increase in corticosterone level was observed. In the early period after exposure a decrease in pineal melatonin occurred, accompanied by a decrease in pineal catecholamines. On the contrary, in the phase of developed radiation injury the signs of increased melatonin synthesis were observed on days 3 and 4 after the exposure. (author) 6 figs., 25 refs

163

Melatonin reduces endoplasmic reticulum stress and preserves sirtuin 1 expression in neuronal cells of newborn rats after hypoxia-ischemia.  

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Conditions that interfere with the endoplasmic reticulum (ER) functions cause accumulation of unfolded proteins in the ER lumen, referred to as ER stress, and activate a homeostatic signaling network known as unfolded protein response (UPR). We have previously shown that in neonatal rats subjected to hypoxia-ischemia (HI), melatonin administration significantly reduces brain damage. This study assessed whether attenuation of ER stress is involved in the neuroprotective effect of melatonin after neonatal HI. We found that the UPR was strongly activated after HI. Melatonin significantly reduced the neuron splicing of XBP-1 mRNA, the increased phosphorylation of eIF2?, and elevated expression of chaperone proteins GRP78 and Hsp70 observed after HI in the brain. CHOP, which plays a convergent role in the UPR, was reduced as well. Melatonin also completely prevented the depletion of SIRT-1 induced by HI, and this effect was observed in the same neurons that over-express CHOP. These results demonstrate that melatonin reduces ER stress induced by neonatal HI and preserves SIRT-1 expression, suggesting that SIRT-1, due to its action in the modulation of a wide variety of signaling pathways involved in neuroprotection, may play a key role in the reduction of ER stress and neuroprotection observed after melatonin. PMID:24980917

Carloni, Silvia; Albertini, Maria Cristina; Galluzzi, Luca; Buonocore, Giuseppe; Proietti, Fabrizio; Balduini, Walter

2014-09-01

164

Utility of melatonin to treat surgical stress after major vascular surgery - a safety study  

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Surgery for abdominal aortic aneurysm is associated with elevated oxidative stress. As an antioxidant in animal and human studies, melatonin has the potential of ameliorating some of this oxidative stress, but melatonin has never been administered to adults during surgery for the purpose of reducing oxidative damage. The aim of this pilot study was to evaluate the safety of various doses of melatonin administered during or after surgery and to monitor the changes in biomarkers of oxidative stress and inflammation during the pre-, intra- and postoperative period. Six patients undergoing aortic surgery received 10 (n=2), 30 (n=2) or 60 (n=2) mg melatonin intravenously in the intraoperative phase and 10 mg orally for three nights after surgery. Patients were monitored for hemodynamic parameters during and after surgery. Any unexpected events during the hospitalization were registered. Blood samples were collected preoperatively and at 5 min, 6 hrs and 24 hrs after clamp removal or after re-circulation of the first leg and the samples were analysed for malondialdehyde (MDA), ascorbic acid (AA), dehydroascorbic acid (DHA) and interleukin-6 (IL-6). Troponin I (TpI) and C-reactive protein (CRP) were also measured for four days after surgery. Melatonin administration did not change hemodynamic parameters (mean arterial pressure or pulse rate) during surgery (P=0.499 and 0.149, respectively), but oxidative stress parameters (MDA and AA) decreased significantly (P=0.014 and 0.001, respectively). There was a significant increase in the inflammatory parameters (IL-6 and CRP) (P=0.001 and 0.001, respectively) and an increase in TpI (P=0.009) as a consequence of surgery. These were not influenced by melatonin treatment. Treatment of patients undergoing major aortic surgery with melatonin intravenously up to 60 mg in the intraoperative phase was safe and without complications. Melatonin may decrease oxidative damage resulting from surgery, but randomized clinical trials are required before definitive conclusions can be drawn regarding the clinical benefit of melatonin in surgical situations.

Kücükakin, Bülent; Lykkesfeldt, Jens

2008-01-01

165

Utility of melatonin to treat surgical stress after major vascular surgery--a safety study.  

DEFF Research Database (Denmark)

Surgery for abdominal aortic aneurysm is associated with elevated oxidative stress. As an antioxidant in animal and human studies, melatonin has the potential of ameliorating some of this oxidative stress, but melatonin has never been administered to adults during surgery for the purpose of reducing oxidative damage. The aim of this pilot study was to evaluate the safety of various doses of melatonin administered during or after surgery and to monitor the changes in biomarkers of oxidative stress and inflammation during the pre-, intra-, and postoperative period. Six patients undergoing aortic surgery received 10 (n = 2), 30 (n = 2) or 60 (n = 2) mg melatonin intravenously in the intraoperative phase and 10 mg orally for three nights after surgery. Patients were monitored for hemodynamic parameters during and after surgery. Any unexpected events during the hospitalization were registered. Blood samples were collected preoperatively and at 5 min, 6 hr and 24 hr after clamp removal or after re-circulation of the first leg and the samples were analyzed for malondialdehyde (MDA), ascorbic acid (AA), dehydroascorbic acid (DHA), and interleukin-6 (IL-6). Troponin I (TpI) and C-reactive protein (CRP) were also measured for 4 days after surgery. Melatonin administration did not change hemodynamic parameters (mean arterial pressure or pulse rate) during surgery (P = 0.499 and 0.149, respectively), but oxidative stress parameters (MDA and AA) decreased significantly (P = 0.014 and 0.001, respectively). There was a significant increase in the inflammatory parameters (IL-6 and CRP) (P = 0.001 and 0.001, respectively) and an increase in TpI (P = 0.009) as a consequence of surgery. These were not influenced by melatonin treatment. Treatment of patients undergoing major aortic surgery with melatonin intravenously up to 60 mg in the intraoperative phase was safe and without complications. Melatonin may decrease oxidative damage resulting from surgery, but randomized clinical trials are required before definitive conclusions can be drawn regarding the clinical benefit of melatonin in surgical situations.

Kücükakin, Bülent; Lykkesfeldt, Jens

2008-01-01

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Differential regulation of kiss1 expression by melatonin and gonadal hormones in male and female Syrian hamsters.  

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In seasonal breeders, reproduction is synchronized to seasons by day length via the pineal hormone melatonin. Recently, we have demonstrated that Kiss1, a key activator of the reproductive function, is down-regulated in sexually inactive hamsters maintained in inhibitory short days (SDs). In rodents, Kiss1 is expressed in the anteroventral periventricular nucleus (AVPV) and in the arcuate nucleus (ARC). Because both the duration of the nocturnal peak of melatonin and circulating sex steroid levels vary with photoperiod, the aim of this study was to determine whether melatonin and sex steroids differentially regulate Kiss1 expression in the ARC and the AVPV. Kiss1 expression was examined by in situ hybridization in both male and female hamsters kept in various experimental conditions, and we observed that 1) SD exposure markedly reduced Kiss1 expression in the ARC and AVPV of male and female hamsters as compared to LD animals, 2) sex steroid treatment in SD-adapted male and female hamsters increased the number of Kiss1 neurons in the AVPV but decreased it in the ARC, 3) melatonin administration to LD-adapted hamsters decreased Kiss1 mRNA level in both the AVPV and the ARC in intact animals, whereas in castrated hamsters, melatonin rapidly inhibited Kiss1 expression in the ARC but not in the AVPV, and 4) pinealectomy of male or female SD-adapted hamsters increased the number of Kiss1 neurons in the ARC but not in the AVPV. In conclusion, our data demonstrate that Kiss1 expression in the Syrian hamster hypothalamus is down-regulated in SD via different mechanisms. In the ARC, melatonin inhibits Kiss1 via a direct effect on the hypothalamus, and this effect is probably sex steroid dependent, whereas in the AVPV, the decrease in Kiss1 expression appears to be secondary to the melatonin-driven reduction of sex steroid levels. Taken together, our data support the hypothesis that ARC Kiss1 neurons mediate melatonin effects on the gonadotropic axis of the Syrian hamster. PMID:20348459

Ansel, L; Bolborea, M; Bentsen, A H; Klosen, P; Mikkelsen, J D; Simonneaux, V

2010-04-01

167

Differential regulation of kiss1 expression by melatonin and gonadal hormones in male and female Syrian hamsters  

DEFF Research Database (Denmark)

In seasonal breeders, reproduction is synchronized to seasons by day length via the pineal hormone melatonin. Recently, we have demonstrated that Kiss1, a key activator of the reproductive function, is down-regulated in sexually inactive hamsters maintained in inhibitory short days (SDs). In rodents, Kiss1 is expressed in the anteroventral periventricular nucleus (AVPV) and in the arcuate nucleus (ARC). Because both the duration of the nocturnal peak of melatonin and circulating sex steroid levels vary with photoperiod, the aim of this study was to determine whether melatonin and sex steroids differentially regulate Kiss1 expression in the ARC and the AVPV. Kiss1 expression was examined by in situ hybridization in both male and female hamsters kept in various experimental conditions, and we observed that 1) SD exposure markedly reduced Kiss1 expression in the ARC and AVPV of male and female hamsters as compared to LD animals, 2) sex steroid treatment in SD-adapted male and female hamsters increased the numberof Kiss1 neurons in the AVPV but decreased it in the ARC, 3) melatonin administration to LD-adapted hamsters decreased Kiss1 mRNA level in both the AVPV and the ARC in intact animals, whereas in castrated hamsters, melatonin rapidly inhibited Kiss1 expression in the ARC but not in the AVPV, and 4) pinealectomy of male or female SD-adapted hamsters increased the number of Kiss1 neurons in the ARC but not in the AVPV. In conclusion, our data demonstrate that Kiss1 expression in the Syrian hamster hypothalamus is down-regulated in SD via different mechanisms. In the ARC, melatonin inhibits Kiss1 via a direct effect on the hypothalamus, and this effect is probably sex steroid dependent, whereas in the AVPV, the decrease in Kiss1 expression appears to be secondary to the melatonin-driven reduction of sex steroid levels. Taken together, our data support the hypothesis that ARC Kiss1 neurons mediate melatonin effects on the gonadotropic axis of the Syrian hamster.

Ansel, L; Bolborea, M

2010-01-01

168

Reversal of the inhibitory effect of light and high temperature on germination of Phacelia tanacetifolia seeds by melatonin.  

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Possible role of melatonin in the germination of negatively photoblastic and thermosensitive seeds of Phacelia tanacetifolia Benth was studied. Final germination percentage (FGP) was determined in the presence or absence of light at various temperatures, ranging from 0 to 40°C. The highest FGP was determined as 48.7% and 92% at temperature of 15°C in the presence and absence of light, respectively. Seeds were primed with 1% KNO(3) containing various concentrations (0.3, 1, 6, 12, 30, 60, or 90 ?M) of melatonin for 2 days at 15°C in darkness. Primed seeds were germinated at an inhibitory temperature of 30°C, and results were compared to those occurring at the optimum temperature of 15°C under both light and no light conditions. Melatonin incorporated into priming medium significantly reversed the inhibitory effects of light and high temperature. Germination was elevated from 2.5% to 52% of FGP for seeds primed in the presence of 6 ?M melatonin in darkness at 30°C, while 1 ?M melatonin had the highest FGP (21.0%) in the presence of light at 30°C. The highest FGP (47.5%) was obtained from seeds primed in the presence of 0.3 ?M melatonin under the light condition at 15°C, while untreated seeds had 1.5% of FGP. The fastest seed germination was determined from seeds primed in the presence of 0.3 ?M melatonin (G(50) = 0.56 days) at 15°C in darkness. The possible roles of melatonin in promoting germination parameters of photo- and thermosensitive seed germination are discussed. PMID:22225610

Tiryaki, Iskender; Keles, Huseyin

2012-04-01

169

Overexpression of MzASMT improves melatonin production and enhances drought tolerance in transgenic Arabidopsis thaliana plants.  

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Melatonin is a potent naturally occurring reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenger in plants. Melatonin protects plants from oxidative stress and, therefore, it improves their tolerance against a variety of environmental abiotic stressors. N-acetylserotonin-O-methyltransferase (ASMT) is a specific enzyme required for melatonin synthesis. In this report, an ASMT gene was cloned from apple rootstock (Malus zumi Mats) and designated as MzASMT1 (KJ123721). The MzASMT1 expression was induced by drought stress in apple leaves. The upregulation of MzASMT1 in the apple leaf positively relates to melatonin production over a 24-hr dark/light cycle. Purified MzASMT1 protein expressed in E. coli converted its substrates to melatonin with an activity of approximately 5.5 pmol/min/mg protein. The transient transformation in tobacco identified that MzASMT1 is located in cytoplasm of the cell. When MzASMT1 gene driven by 35S promoter was transferred to Arabidopsis, melatonin levels in transgenic Arabidopsis plants were 2-4 times higher than those in the wild type. The transgenic Arabidopsis plants had significantly lower intrinsic ROS than the wild type and therefore these plants exhibited greater tolerance to drought stress than that of wild type. This is, at least partially, attributed to the elevated melatonin levels resulting from the overexpression of MzASMT1. The results elucidated the important role that membrane-located melatonin synthase plays in drought tolerance. These findings have significant implications in agriculture. PMID:25250844

Zuo, Bixiao; Zheng, Xiaodong; He, Pingli; Wang, Lin; Lei, Qiong; Feng, Chao; Zhou, Jingzhe; Li, Qingtian; Han, Zhenhai; Kong, Jin

2014-11-01

170

Impacts of Mixing Processes in Nocturnal Atmospheric Boundary Layer on Urban Ozone Concentrations  

Science.gov (United States)

A number of open questions remain regarding the role of low-level jets (LLJs) and nocturnal mixing processes in the buildup of tropospheric ozone. The prevalence of southerly winds and LLJs in the U.S. Southern Great Plains during summer makes this region an ideal site for investigating the structure of the nocturnal boundary layer and its impacts on urban air quality. Ozone and nitrogen oxide concentrations measured at regulatory monitoring sites in the Oklahoma City (OKC) area and simulations with the Weather Research and Forecasting with Chemistry (WRF/Chem) model were analyzed to show how the nocturnal LLJ moderates boundary-layer mixing processes and air quality. Datasets collected during the Joint Urban 2003 campaign, which took place in July 2003 in OKC, provided detailed information about nocturnal boundary-layer structure and dynamics. In general, time series show the expected behavior that urban concentrations decrease at night due to nitrogen oxide titration reactions, but elevated concentrations and secondary peaks are also seen quite frequently after sunset. LLJs developed on most nights during the study period and were associated with strong vertical wind shear, which affected the boundary-layer stability and structure. Near-surface concentrations are higher during less stable nights when active mixing persists throughout the night. The WRF/Chem model results agree well with the observations and further demonstrate the role of LLJs in moderating nocturnal mixing processes and air quality. The highest nocturnal concentrations are linked to a strong LLJ that promotes both nocturnal long-range transport and persistent downward mixing of from the residual layer to the surface.

Klein, Petra M.; Hu, Xiao-Ming; Xue, Ming

2014-01-01

171

Design and rationale of a randomized controlled trial of melatonin supplementation in men and women with the metabolic syndrome  

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Full Text Available Paul D Terry,1 Abhinav Goyal,2,3 Lawrence S Phillips,3 Hillary M Superak,4 Michael H Kutner4 1Departments of Public Health and Surgery, University of Tennessee, Knoxville, TN, 2Department of Epidemiology, Emory Rollins School of Public Health, 3Department of Medicine, Emory School of Medicine, 4Department of Biostatistics and Bioinformatics, Emory Rollins School of Public Health, Atlanta, GA, USA Background: The metabolic syndrome is a constellation of interrelated metabolic risk factors that appear to increase the risk of atherosclerotic cardiovascular disease, type 2 diabetes mellitus, and possibly some cancers. Animal studies and observational clinical data in humans suggest that supplemental melatonin may ameliorate a number of components of the metabolic syndrome, including elevated glucose, elevated blood pressure, dyslipidemia, and obesity. The primary objective of this clinical trial was to determine the feasibility, efficacy, and safety of melatonin supplementation in men and women with the metabolic syndrome. Methods: Thirty-nine men and women of mixed race/ethnicity were enrolled into a randomized, double-blind, placebo-controlled clinical trial with two arms: placebo for 10 weeks followed by melatonin for 10 weeks, or vice versa, with an interval 6-week washout period, in a crossover trial design. Outcome measures include metabolic syndrome components (blood pressure, glucose, triglycerides, high-density lipoprotein cholesterol, waist circumference, oxidative stress, and inflammation biomarkers. These biomarkers, along with sleep duration and quality and pretreatment endogenous melatonin levels, were measured to explore possible underlying biologic mechanisms. Discussion: This trial will provide knowledge of the effects of melatonin in metabolic syndrome subjects, and lay the groundwork for future clinical trials of melatonin in metabolic syndrome subjects. Keywords: melatonin, metabolic syndrome, diabetes, blood pressure, sleep

Terry PD

2013-03-01

172

Effects of exposure to intermittent versus continuous red light on human circadian rhythms, melatonin suppression, and pupillary constriction.  

Science.gov (United States)

Exposure to light is a major determinant of sleep timing and hormonal rhythms. The role of retinal cones in regulating circadian physiology remains unclear, however, as most studies have used light exposures that also activate the photopigment melanopsin. Here, we tested the hypothesis that exposure to alternating red light and darkness can enhance circadian resetting responses in humans by repeatedly activating cone photoreceptors. In a between-subjects study, healthy volunteers (n?=?24, 21-28 yr) lived individually in a laboratory for 6 consecutive days. Circadian rhythms of melatonin, cortisol, body temperature, and heart rate were assessed before and after exposure to 6 h of continuous red light (631 nm, 13 log photons cm(-2) s(-1)), intermittent red light (1 min on/off), or bright white light (2,500 lux) near the onset of nocturnal melatonin secretion (n?=?8 in each group). Melatonin suppression and pupillary constriction were also assessed during light exposure. We found that circadian resetting responses were similar for exposure to continuous versus intermittent red light (P?=?0.69), with an average phase delay shift of almost an hour. Surprisingly, 2 subjects who were exposed to red light exhibited circadian responses similar in magnitude to those who were exposed to bright white light. Red light also elicited prolonged pupillary constriction, but did not suppress melatonin levels. These findings suggest that, for red light stimuli outside the range of sensitivity for melanopsin, cone photoreceptors can mediate circadian phase resetting of physiologic rhythms in some individuals. Our results also show that sensitivity thresholds differ across non-visual light responses, suggesting that cones may contribute differentially to circadian resetting, melatonin suppression, and the pupillary light reflex during exposure to continuous light. PMID:24797245

Ho Mien, Ivan; Chua, Eric Chern-Pin; Lau, Pauline; Tan, Luuan-Chin; Lee, Ivan Tian-Guang; Yeo, Sing-Chen; Tan, Sara Shuhui; Gooley, Joshua J

2014-01-01

173

Melatonin in Alzheimer’s Disease  

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Full Text Available Alzheimer’s disease (AD, an age-related neurodegenerative disorder with progressive cognition deficit, is characterized by extracellular senile plaques (SP of aggregated ?-amyloid (A? and intracellular neurofibrillary tangles, mainly containing the hyperphosphorylated microtubule-associated protein tau. Multiple factors contribute to the etiology of AD in terms of initiation and progression. Melatonin is an endogenously produced hormone in the brain and decreases during aging and in patients with AD. Data from clinical trials indicate that melatonin supplementation improves sleep, ameliorates sundowning and slows down the progression of cognitive impairment in AD patients. Melatonin efficiently protects neuronal cells from A?-mediated toxicity via antioxidant and anti-amyloid properties. It not only inhibits A? generation, but also arrests the formation of amyloid fibrils by a structure-dependent interaction with A?. Our studies have demonstrated that melatonin efficiently attenuates Alzheimer-like tau hyperphosphorylation. Although the exact mechanism is still not fully understood, a direct regulatory influence of melatonin on the activities of protein kinases and protein phosphatases is proposed. Additionally, melatonin also plays a role in protecting the cholinergic system and in anti-inflammation. The aim of this review is to stimulate interest in melatonin as a potentially useful agent in the prevention and treatment of AD.

Jian-Zhi Wang

2013-07-01

174

Melatonin in human preovulatory follicular fluid  

Science.gov (United States)

Melatonin, the major hormone of the pineal gland, has antigonadotrophic activity in many mammals and may also be involved in human reproduction. Melatonin suppresses steroidogenesis by ovarian granulosa and luteal cells in vitro. To determine if melatonin is present in the human ovary, preovulatory follicular fluids (n = 32) from 15 women were assayed for melatonin by RIA after solvent extraction. The fluids were obtained by laparoscopy or sonographically controlled follicular puncture from infertile women undergoing in vitro fertilization and embryo transfer. All patients had received clomiphene citrate, human menopausal gonadotropin, and hCG to stimulate follicle formation. Blood samples were obtained by venipuncture 30 min or less after follicular aspiration. All of the follicular fluids contained melatonin, in concentrations (35.6 plus or minus 4.8 (plus or minus SEM) pg/mL) substantially higher than those in the corresponding serum (10.0 plus or minus 1.4 pg/mL). A positive correlation was found between follicular fluid and serum melatonin levels in each woman (r = 0.770; P less than 0.001). These observations indicate that preovulatory follicles contain substantial amounts of melatonin that may affect ovarian steroidogenesis.

Brzezinski, Amnon; Seibel, Machelle M.; Lynch, Harry J.; Deng, Mei-Hua; Wurtman, Richard J.

1987-01-01

175

Melatonin: General Features and its Role in Psychiatric Disorders  

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Full Text Available In recent years, there is a growing interest in melatonin all over the world. The main task of protecting the body's biological clock, which set the rhythm of melatonin, involves many biological and physiological processes of the body. Cell renewal, strengthening of the immune system and body temperature regulation are other tasks of melatonin. Melatonin, with its lipophilic property, is the most powerful antioxidant as it can reach all body areas and can easily pass the blood-brain barrier. The fact that individuals with low levels of melatonin have sleep problems lead to the consideration of melatonin as a therapeutic medicine in this field. The detailed researches have shown that melatonin can improve sleep quality without changing the total duration of sleep. Nevertheless, despite high number of researches done, the functions of melatonin have not yet fully understood. Therefore, review of the available information related to melatonin will be guide for researchers in the field.

Murat Erdem

2013-06-01

176

Melatonin as a radioprotective agent: a review  

International Nuclear Information System (INIS)

Melatonin (N-acetyl-5-methoxytryptamine), the chief secretory product of the pineal gland in the brain, is well known for its functional versatility. In hundreds of investigations, melatonin has been documented as a direct free radical scavenger and an indirect antioxidant, as well as an important immunomodulatory agent. The radical scavenging ability of melatonin is believed to work via electron donation to detoxify a variety of reactive oxygen and nitrogen species, including the highly toxic hydroxyl radical. It has long been recognized that the damaging effects of ionizing radiation are brought about by both direct and indirect mechanisms. The direct action produces disruption of sensitive molecules in the cells, whereas the indirect effects (?70%) result from its interaction with water molecules, which results in the production of highly reactive free radicals such as ·OH, ·H, and eaq- and their subsequent action on subcellular structures. The hydroxyl radical scavenging ability of melatonin was used as a rationale to determine its radioprotective efficiency. Indeed, the results from many in vitro and in vivo investigations have confirmed that melatonin protects mammalian cells from the toxic effects of ionizing radiation. Furthermore, several clinical reports indicate that melatonin administration, either alone or in combination with traditional radiotherapy, results in a favorable efficacy:toxicity ratio during theble efficacy:toxicity ratio during the treatment of human cancers. This article reviews the literature from laboratory investigations that document the ability of melatonin to scavenge a variety of free radicals (including the hydroxyl radical induced by ionizing radiation) and summarizes the evidence that should be used to design larger translational research-based clinical trials using melatonin as a radioprotector and also in cancer radiotherapy. The potential use of melatonin for protecting individuals from radiation terrorism is also considered

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Influence of light-dark and lunar cycles on the ocular melatonin rhythms in the seagrass rabbitfish, a lunar-synchronized spawner.  

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The aim of this study was to investigate the effects of light-dark (LD) cycles and lunar phases on ocular melatonin rhythms in the seagrass rabbitfish, Siganus canaliculatus, a lunar-synchronized spawner. Under a natural 24-hr LD (12.00:12.00) cycle, ocular melatonin levels were low during daylight hours. The levels significantly elevated to peak during the mid-dark phase at 24.00 hr and then declined sharply in the early morning around 06.00 hr. These rhythms disappeared under either constant light (LL) or constant dark (DD) conditions. Melatonin levels remained low in LL compared with those in DD condition. These results suggest that ocular melatonin rhythms in the seagrass rabbitfish are suppressed in the presence of light. When fish were exposed to natural moon phases, ocular melatonin concentrations were higher around the new moon than both the first quarter and full moon phases. Exposure to experimental new moon conditions caused a significant increase in melatonin levels while those of the fish exposed to experimental full moon conditions were decreased. These results suggest that the seagrass rabbitfish perceives moonlight through the eye and that moonlight directly causes melatonin suppression. PMID:15298671

Rahman, Md Saydur; Kim, Byung-Ho; Takemura, Akihiro; Park, Chang-Bum; Lee, Young-Don

2004-09-01

178

MT1 melatonin receptors and their role in the oncostatic action of melatonin  

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Full Text Available Melatonin, the main hormone produced by the pineal gland, strongly inhibits the growth of cancer cells [i]in vitro[/i] and [i]in vivo[/i]. Some publications indicate that the addition of melatonin to culture medium slows the proliferation of some cancer cell lines. It is also suggested that melatonin used as an adjuvant benefits the effectiveness and tolerance of chemotherapy. The mechanisms of this are not fully understood, but melatonin receptors might be one of the most important elements. Two distinct types of membrane-bound melatonin receptors have been identified in humans: MT1 (Mel1a and MT2 (Mel1b receptors. These subtypes are 60?0homologous at the amino-acid level. MT1 receptors are G-protein-coupled receptors. Through the ? subunit of G protein, melatonin receptors stimulate an adenylate cyclase and decrease the level of cAMP. This has a significant influence on cell proliferation and has been confirmed in many tests on different cell lines, such as S-19, B-16 murine melanoma cells, and breast cancer cells. It seems that expression of the MT1 melatonin receptors benefits the efficacy of melatonin treatment. Melatonin and its receptors may provide a promising way to establish new alternative therapeutic approaches in human cancer prevention.

Karolina Danielczyk

2009-09-01

179

Nocturnal Enuresis and its Impact on Growth  

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Full Text Available Objective: Nocturnal enuresis is a common developmental-behavioral problem in children. The present study was conducted to estimate the prevalence of primary nocturnal enuresis and to determine its impact on physical growth of the first grade elementary school children. Material & Methods: This is a cross-sectional study carried out on 350 first-grade children (6 to 6.5 yr old elementary schools in Gonabad through random stratified sampling. All children had primary nocturnal enuresis. A questionnaire containing demographic criteria and various factors that may play a role in bed-wetting was filled out; a digital scale and a non-expanding measuring tape were used to collect data. Diagnosis of enuresis considered nocturnal voiding twice a week for at least three consecutive months. Findings: The prevalence of primary nocturnal enuresis was 21% for boys and 14.9% for girls, and the overall prevalence was 17.5%. The average weight of enuretic children was lower than that of the non-affected ones. In addition, these children were in average shorter compared to those without enuresis. Conclusion: This study demonstrates that growth failure is a coexisting problem in children with primary nocturnal enuresis. Since enuresis and other stressful conditions in family can cause growth failure in children, the treatment of enuresis eliminating a stressful condition could be an effective measure in improving childrens physical growth.

AmirAli Ghahramani

2008-05-01

180

Alpha-2 adrenergic activity of bromocriptine and quinpirole in chicken pineal gland. Effects on melatonin synthesis and ( sup 3 H)rauwolscine binding  

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In the pineal gland and retina of chickens, serotonin N-acetyl-transferase (NAT) activity and melatonin content are modulated by different receptors, alpha-2 adrenergic receptors in pineal gland and D2-dopamine receptors in retina. The effect of two D2-dopamine receptor agonists, bromocriptine and quinpirole (LY 171555), on melatonin synthesis in these tissues was investigated. Systemic administrations of bromocriptine and quinpirole decreased nocturnal NAT activity and melatonin content of both pineal gland and retina. Bromocriptine was equipotent in the two tissues, whereas quinpirole was approximately 100-fold more potent in retina than in pineal gland. In pineal gland, the suppressive effects of bromocriptine and quinpirole on NAT activity were blocked by yohimbine, a selective alpha-2 adrenergic receptor antagonist, but not by spiperone, a D2-dopamine receptor antagonist. In contrast, bromocriptine- and quinpirole-induced decreases of the enzyme activity in retina were antagonized by spiperone, and not affected by yohimbine. The nocturnal increase of NAT activity of pineal glands in vitro was inhibited with an order of potency clonidine greater than bromocriptine greater than quinpirole. Additionally, bromocriptine and quinpirole displaced the specific binding of (3H)rauwolscine, an alpha-2 adrenergic receptor antagonist, to membranes from chicken pineal gland, with potencies comparable to those observed for inhibition of NAT activity in vitro. It is suggested that bromocriptine and quinpirole, in addition to their D2-dopaminergic activity, can stimulate alpha-2 adrenergic receptors in pineal gland of chicken.

Zawilska, J.; Iuvone, P.M. (Emory Univ. School of Medicine, Atlanta, GA (USA))

1990-12-01

 
 
 
 
181

Alpha-2 adrenergic activity of bromocriptine and quinpirole in chicken pineal gland. Effects on melatonin synthesis and [3H]rauwolscine binding  

International Nuclear Information System (INIS)

In the pineal gland and retina of chickens, serotonin N-acetyl-transferase (NAT) activity and melatonin content are modulated by different receptors, alpha-2 adrenergic receptors in pineal gland and D2-dopamine receptors in retina. The effect of two D2-dopamine receptor agonists, bromocriptine and quinpirole (LY 171555), on melatonin synthesis in these tissues was investigated. Systemic administrations of bromocriptine and quinpirole decreased nocturnal NAT activity and melatonin content of both pineal gland and retina. Bromocriptine was equipotent in the two tissues, whereas quinpirole was approximately 100-fold more potent in retina than in pineal gland. In pineal gland, the suppressive effects of bromocriptine and quinpirole on NAT activity were blocked by yohimbine, a selective alpha-2 adrenergic receptor antagonist, but not by spiperone, a D2-dopamine receptor antagonist. In contrast, bromocriptine- and quinpirole-induced decreases of the enzyme activity in retina were antagonized by spiperone, and not affected by yohimbine. The nocturnal increase of NAT activity of pineal glands in vitro was inhibited with an order of potency clonidine greater than bromocriptine greater than quinpirole. Additionally, bromocriptine and quinpirole displaced the specific binding of [3H]rauwolscine, an alpha-2 adrenergic receptor antagonist, to membranes from chicken pineal gland, with potencies comparable to those observed for inhibition of NAT activity in vitro. It is suggested that bromocriptine and quinpirole, in addition to their D2-dopaminergic activity, can stimulate alpha-2 adrenergic receptors in pineal gland of chicken

182

Pharmacology and function of melatonin receptors  

International Nuclear Information System (INIS)

thoxymelatonin greater than N-acetyltryptamine greater than or equal to luzindole greater than N-acetyl-5-hydroxytryptamine greater than 5-methoxytryptamine much greater than 5-hydroxytryptamine) be classified as ML-1 (melatonin 1). The 2-[125I]iodomelatonin binding site of hamster brain membranes possesses different binding and pharmacological characteristics from the retinal melatonin receptor site and should be classified as ML-2. 64 references

183

Circadian uses of melatonin in humans.  

Science.gov (United States)

Melatonin in humans can be an independent or dependent variable. Measurement of endogenous melatonin levels under dim-light conditions, particularly the dim-light melatonin onset (DLMO), has received increasing attention among researchers, and for clinicians it may soon become a convenient test that can be done at home using saliva collections in the evening, without interfering with sleep. Melatonin, even at low physiological doses, can cause advances (shifts to an earlier time) or delays (shifts to a later time) depending on when it is administered on its phase-response curve (in most sighted people, these times are approximately in the p.m. and in the a.m., respectively). Although both bright light and melatonin can be used separately or together in the treatment of circadian phase disorders in sighted people-such as advanced and delayed sleep phase syndromes, jet lag, shift-work maladaptation, and winter depression (seasonal affective disorder, or SAD)-melatonin is the treatment of choice in totally blind people. These people provide a unique opportunity to study the human circadian system without the overwhelming effects of ocularly mediated light, thus permitting us to establish that all blind free-runners (BFRs) studied under high resolution appear to have phase-advancing and phase-delaying responses to as yet unidentified zeitgebers (time givers) that are usually too weak to result in entrainment. PMID:16687313

Lewy, Alfred J; Emens, Jonathan; Jackman, Angela; Yuhas, Krista

2006-01-01

184

Loss of Response to Melatonin Treatment Is Associated with Slow Melatonin Metabolism  

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Background: In some of our patients with intellectual disability (ID) and sleep problems, the initial good response to melatonin disappeared within a few weeks after starting treatment, while the good response returned only after considerable dose reduction. The cause for this loss of response to melatonin is yet unknown. We hypothesise that this…

Braam, W.; van Geijlswijk, I.; Keijzer, Henry; Smits, Marcel G.; Didden, Robert; Curfs, Leopold M. G.

2010-01-01

185

The effect of sleep on nocturnal urine output  

DEFF Research Database (Denmark)

  Hypothesis / aims of studyAim of this study was to elucidate the impact of sleep on the quantity and quality of the nocturnal urine production in healthy individuals.Our hypothesis was that sleep deprivation is related to excess nocturnal urine production.Study design, materials and methodsThe study protocol was approved by the local Ethics Committee.Twenty healthy volunteers with no history of enuresis, incontinence or nocturia were investigated in the present study. The participants were admitted in the hospital for two 24-hour periods under standardized conditions regarding sodium (2 mmol/kg) and water (25 ml/kg). Normal activities were allowed during the day. Blood samples were drawn every 3 hours and urine was fractionally collected with 3-hour intervals during daytime and following spontaneous voidings at night. During one of the two experimental 24-hour periods subjects were deprived from sleep and the sequence was randomized. During these nights with sleep deprivation, participants were in lying position in a dimly lit room and physical activities, food and fluid intake were not allowed. Smoking was not allowed throughout the entire experimental protocol. Determinations of electrolytes (Na+, K+, Ca2+) creatinine, urea and osmolality were made in plasma and urine. Blood pressure and heart rate were monitored every hour, using an ambulatory device. Arginine vasopressin (AVP) was measured in plasma by means of radioimmunoassay. Prostaglandin E2 (PGE2) was directly measured in urine using an enzyme immunoassay. 6-sulfatoxy-melatonin (MEL) was measured in urine using and ELISA assay. Clearances, excretions and fractional excretions were calculated for electrolytes, creatinine, urea, osmoles and solute free water. Comparisons were made between the nights with and without sleep deprivation. The circadian rhythm of AVP, PGE2 and MEL was evaluated at baseline and during sleep deprivation.ResultsNo significant differences were found in the urinary production at daytime between the two experimental 24-h periods. Males excreted significantly higher amounts of urine on a 24-h basis. During nighttime and on the nights of sleep deprivation, both males and females produced markedly larger amounts of urine even though the effect was more pronounced for males (males from 1.05 ± 0.10 ml/h/kg to 1.82 ± 0.22 ml/h/kg, p<0.001, females from 0.98 ± 0.09 ml/h/kg to 1.41 ± 0.11 ml/h/kg). A similar effect was found for the urinary excretion of sodium (baseline: 0.06 ± 0.01 mmol/kg/h, sleep deprivation: 0.12 ± 0.01 mmol/kg/h), potassium and urine osmolality (baseline: 416 ± 142 mosm/kg, sleep deprivation: 366 ± 66 mosm/kg). No differences were seen in urinary calcium excretion between baseline night and the night with sleep deprivation. The circadian rhythm in plasma AVP was not influenced by sleep deprivation. In accordance with this, solute free water reabsorption was not significantly different between baseline and during sleep deprivation (baseline 0.45 ± 0.08, sleep deprivation 0.47 ± 0.07 ml/min).We found a significant correlation between hemodynamics as these were assessed by blood pressure and heart rate and the degree of nocturnal polyuria following sleep deprivation.Interpretation of resultsResearch into the field of incontinence has therefore during the past years taken sleep related physiological mechanisms into consideration. In the present study we report that acute sleep deprivation has a dramatic effect on the volume of nocturnal urine production in both genders although the effect is more pronounced in males. Natriuresis and kaliuresis were observed on nights with sleep deprivation and were related to differences in hemodynamics between nights with and without sleep deprivation. The circadian rhythms in AVP, PGE2 and melatonin all seem unaffected by sleep deprivation. Furthermore renal water handling was not influenced by sleep deprivation. Concluding messageSleep seems to be a major regulator of urine production at night and its deprivation leads to natriuresis, kaliuresis and the production of excess amounts

Kamperis, Konstantinos; HagstrØm, SØren

2005-01-01

186

Human Puberty: Salivary Melatonin Profiles in Constant Conditions  

Science.gov (United States)

This analysis examined the relative contributions of sex, age, body mass index (BMI), and puberty (Tanner) stage on salivary melatonin amplitude. Sixty-nine children and adolescents (30 females; 9.6–17.8 years) were examined for Tanner stage. Serial salivary melatonin samples were collected in controlled conditions, from which these melatonin amplitude measures were derived: area under the curve (AUC) and maximum value (MAX). AUC declined with advancing Tanner stage. This melatonin decline was similar between boys and girls, but girls secreted more melatonin compared to boys. Tanner stage and sex explained AUC variability, but age and BMI did not; similar results emerged for MAX. These results indicate that puberty stage may either mediate the decline of melatonin, or the decrease in melatonin amplitude may be an indicator of pubertal progression. These findings also indicate that the melatonin decline during puberty is not entirely accounted for by body mass or by age. PMID:21953482

Crowley, Stephanie J.; Acebo, Christine; Carskadon, Mary A.

2014-01-01

187

Melatonin Doesn't Curb Delirium After Surgery  

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... sharing features on this page, please enable JavaScript. Melatonin Doesn't Curb Delirium After Surgery Study finds ... Dietary Supplements TUESDAY, Sept. 2, 2014 (HealthDay News) -- Melatonin supplements did not reduce delirium in seniors who ...

188

Putative melatonin receptors in a human biological clock  

International Nuclear Information System (INIS)

In vitro autoradiography with 125I-labeled melatonin was used to examine melatonin binding sites in human hypothalamus. Specific 125I-labeled melatonin binding was localized to the suprachiasmatic nuclei, the site of a putative biological clock, and was not apparent in other hypothalamic regions. Specific 125I-labeled melatonin binding was consistently found in the suprachiasmatic nuclei of hypothalami from adults and fetuses. Densitometric analysis of competition experiments with varying concentrations of melatonin showed monophasic competition curves, with comparable half-maximal inhibition values for the suprachiasmatic nuclei of adults (150 picomolar) and fetuses (110 picomolar). Micromolar concentrations of the melatonin agonist 6-chloromelatonin completely inhibited specific 125I-labeled melatonin binding, whereas the same concentrations of serotonin and norepinephrine caused only a partial reduction in specific binding. The results suggest that putative melatonin receptors are located in a human biological clock

189

A radiobiological review on melatonin. A novel radioprotector  

International Nuclear Information System (INIS)

atonin may be effective for a variety of disorders, the optimum dose of melatonin for human radioprotection is yet to be determined by further research. We propose that, in the future melatonin improve therapeutic ratio in radiation oncology.

190

Can nocturnal hypertension predict cardiovascular risk?  

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Full Text Available Oded Friedman1, Alexander G Logan21Samuel Lunenfeld Research Institute, Division of Nephrology, Mount Sinai Hospital, 2Mount Sinai Hospital and University Health Network and Department of Medicine, University of Toronto, Toronto, CanadaAbstract: Nocturnal hypertension and non-dipping of blood pressure during sleep are distinct entities that often occur together and are regarded as important harbingers of poor cardiovascular prognosis. This review addresses several aspects related to these blood pressure abnormalities including definitions, diagnostic limitations, pathogenesis and associated patient profiles, prognostic significance, and therapeutic strategies. Taken together, persistent nocturnal hypertension and non-dipping blood pressure pattern, perhaps secondary to abnormal renal sodium handling and/or altered nocturnal sympathovagal balance, are strongly associated with deaths, cardiovascular events, and progressive loss of renal function, independent of daytime and 24-hour blood pressure. Several pharmacological and non-pharmacological approaches may restore nocturnal blood pressure and circadian blood pressure rhythm to normal; however, whether this translates to a clinically meaningful reduction in unfavorable cardiovascular and renal consequences remains to be seen.Keywords: blood pressure, sleep, nocturnal hypertension

Oded Friedman

2009-09-01

191

Genetics Home Reference: Autosomal dominant nocturnal frontal lobe epilepsy  

Science.gov (United States)

... disorder catalog Conditions > Autosomal dominant nocturnal frontal lobe epilepsy (often shortened to ADNFLE ) On this page: Description ... What is ADNFLE? Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is an uncommon form of epilepsy that ...

192

Selenium-vitamin E combination and melatonin modulates diabetes-induced blood oxidative damage and fetal outcomes in pregnant rats.  

Science.gov (United States)

Oxidative stress is considered to be the main cause of diabetic complications. In the current study, we investigated the effect of selenium-vitamin E combination and melatonin on lipid peroxidation (LPO) and scavenging enzyme activity in the blood of streptozocin (STZ)-induced diabetic pregnant rats. Forty female Wistar rats were randomly divided into five groups. The first and second groups were used as the non-pregnant control and pregnant control groups, respectively. The third group was the pregnant diabetic group. Vitamin E plus selenium and melatonin were administered to the diabetic pregnant rats consisting fourth and fifth groups, respectively. Diabetes was induced on day 0 of the study by STZ. Blood samples were taken from all animals on the 20th day of pregnancy. LPO level was higher in diabetic pregnant rats than in control, although superoxide dismutase, catalase, and glutathione peroxidase activities were lower in diabetic pregnant animals than in control. LPO levels were lower both in the two treatment groups than in the diabetic pregnant rats, whereas selenium-vitamin E combination and melatonin caused a significant increase in the activities of these antioxidant enzymes (pdiabetic pregnant rats. Melatonin did not significantly affect the elevated glucose concentration of diabetic pregnant treated with melatonin group. Vitamin E plus selenium may play a role in preventing diabetes-related diseases of pregnant subjects. PMID:21240568

Guney, Mehmet; Erdemoglu, Evrim; Mungan, Tamer

2011-11-01

193

Vision and visual navigation in nocturnal insects.  

Science.gov (United States)

With their highly sensitive visual systems, nocturnal insects have evolved a remarkable capacity to discriminate colors, orient themselves using faint celestial cues, fly unimpeded through a complicated habitat, and navigate to and from a nest using learned visual landmarks. Even though the compound eyes of nocturnal insects are significantly more sensitive to light than those of their closely related diurnal relatives, their photoreceptors absorb photons at very low rates in dim light, even during demanding nocturnal visual tasks. To explain this apparent paradox, it is hypothesized that the necessary bridge between retinal signaling and visual behavior is a neural strategy of spatial and temporal summation at a higher level in the visual system. Exactly where in the visual system this summation takes place, and the nature of the neural circuitry that is involved, is currently unknown but provides a promising avenue for future research. PMID:20822443

Warrant, Eric; Dacke, Marie

2011-01-01

194

Nocturnal acid breakthrough: consequences and confronting  

Directory of Open Access Journals (Sweden)

Full Text Available SUMMARY Nocturnal Acid Breakthrough is defined as the appearance of gastric acid in the antrum of pH<4 overnight for a period longer than one hour during the administration of proton pump inhibitors. The prevalence of this phenomenon ranges between 69-79% in normal volunteers and patients with gastroesophageal reflux disease respectively. It typically appears in the second 6-hour period after the evening dose of a PPI when patients are sleeping. The significance of nocturnal acid breakthrough is uncertain despite intense clinical and laboratory investigation. The available data do not lead to firm conclusions, so this interesting matter requires more research in different parts of the world. The relationship between Helicobacter pylori infection and nocturnal acid breakthrough both in health and upper GI disorders disease has not been fully investigated. However, it seems that the Helicobacter pylori status must be taken into account when dealing with nocturnal acid breakthrough, both in patients and normal controls. Despite the fact that data concerning the exact significance of nocturnal acid breakthrough are not conclusive it must be stressed that it is a common phenomenon in proton pump inhibitor therapy. Although esophageal reflux in not a frequent event, it is more likely to occur in patients with poor motility, severe gastroesophageal reflux disease, Barrett?s esophagus and scleroderma. It seems that in every day clinical practice, the administration of a proton pump inhibitor before meals and ranitidine at bedtime may well be the most cost-effective method available to control gastroesophageal reflux disease.Key Words: Nocturnal acid breakthrough, Reflux, Gastroesophageal reflux disease, Helicobacter pylori, Extraesophageal manifestations of GERD, H2 receptor antagonists, Proton pump inhibitors

K. Triantafillidis, Maria Mylonaki, F. Georgopoulos

2007-03-01

195

Nocturnal acid breakthrough: consequences and confronting  

Directory of Open Access Journals (Sweden)

Full Text Available SUMMARY Nocturnal Acid Breakthrough is defined as the appearance of gastric acid in the antrum of pH<4 overnight for a period longer than one hour during the administration of proton pump inhibitors. The prevalence of this phenomenon ranges between 69-79% in normal volunteers and patients with gastroesophageal reflux disease respectively. It typically appears in the second 6-hour period after the evening dose of a PPI when patients are sleeping. The significance of nocturnal acid breakthrough is uncertain despite intense clinical and laboratory investigation. The available data do not lead to firm conclusions, so this interesting matter requires more research in different parts of the world. The relationship between Helicobacter pylori infection and nocturnal acid breakthrough both in health and upper GI disorders disease has not been fully investigated. However, it seems that the Helicobacter pylori status must be taken into account when dealing with nocturnal acid breakthrough, both in patients and normal controls. Despite the fact that data concerning the exact significance of nocturnal acid breakthrough are not conclusive it must be stressed that it is a common phenomenon in proton pump inhibitor therapy. Although esophageal reflux in not a frequent event, it is more likely to occur in patients with poor motility, severe gastroesophageal reflux disease, Barrett?s esophagus and scleroderma. It seems that in every day clinical practice, the administration of a proton pump inhibitor before meals and ranitidine at bedtime may well be the most cost-effective method available to control gastroesophageal reflux disease. Key Words: Nocturnal acid breakthrough, Reflux, Gastroesophageal reflux disease, Helicobacter pylori, Extraesophageal manifestations of GERD, H2 receptor antagonists, Proton pump inhibitors

J.K. Triantafillidis, Maria Mylonaki, F. Georgopoulos

2007-03-01

196

Melatonin Plays a Protective Role in Postburn Rodent Gut Pathophysiology  

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Full Text Available Melatonin is a possible protective agent in postburn gut pathophysiological dynamics. We investigated the role of endogenously-produced versus exogenously-administered melatonin in a major thermal injury rat model with well-characterized gut inflammatory complications. Our rationale is that understanding in vivo melatonin mechanisms in control and inflamed tissues will improve our understanding of its potential as a safe anti-inflammatory/antioxidant therapeutic alternative. Towards this end, we tested the hypothesis that the gut is both a source and a target for melatonin and that mesenteric melatonin plays an anti-inflammatory role following major thermal injury in rats with 3rd degree hot water scald over 30% TBSA. Our methods for assessing the gut as a source of melatonin included plasma melatonin ELISA measurements in systemic and mesenteric circulation as well as rtPCR measurement of jejunum and terminal ileum expression of the melatonin synthesizing enzymes arylalkylamine N-acetyltransferase (AA-NAT and 5-hydroxyindole-O-methyltransferase (HIOMT in sham versus day-3 postburn rats. Our melatonin ELISA results revealed that mesenteric circulation has much higher melatonin than systemic circulation and that both mesenteric and systemic melatonin levels are increased three days following major thermal injury. Our rtPCR results complemented the ELISA data in showing that the melatonin synthesizing enzymes AA-NAT and HIOMT are expressed in the ileum and jejunum and that this expression is increased three days following major thermal injury. Interestingly, the rtPCR data also revealed negative feedback by melatonin as exogenous melatonin supplementation at a dose of 7.43 mg (32 ?mole/kg, but not 1.86 mg/kg (8 ?mole/kg drastically suppressed AA-NAT mRNA expression. Our methods also included an assessment of the gut as a target for melatonin utilizing computerized immunohistochemical measurements to quantify the effects of exogenous melatonin supplementation on postburn gut mucosa barrier inflammatory profiles. Here, our results revealed that daily postburn intraperitoneal melatonin administration at a dose of 1.86 mg/kg (8 ?mole/kg significantly suppressed both neutrophil infiltration and tyrosine nitrosylation as revealed by Gr-1 and nitrotyrosine immunohistochemistry, respectively. In conclusion, our results provide support for high mesenteric melatonin levels and dynamic de novo gut melatonin production, both of which increase endogenously in response to major thermal injury, but appear to fall short of abrogating the excessive postburn hyper-inflammation. Moreover, supplementation by exogenous melatonin significantly suppresses gut inflammation, thus confirming that melatonin is protective against postburn inflammation.

Walid M. Al-Ghoul, Steven Abu-Shaqra, Byeong Gyu Park, Nadeem Fazal

2010-01-01

197

Paroxysmal nocturnal hemoglobinuria in systemic lupus erythematosus: a case report  

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Abstract Introduction Paroxysmal nocturnal hemoglobinuria is an acquired disorder of hemopoiesis and is characterized by recurrent episodes of intravascular hemolysis due to an increased sensitivity to complement-mediated hemolysis. Systemic lupus erythematosus with paroxysmal nocturnal hemoglobinuria is very rare. We report a case of paroxysmal nocturnal hemoglobinuria that developed in a patient with systemic lupus erythematosus and lupus nephritis. Case presentation...

Nakamura Norio; Sugawara Toshiyuki; Shirato Ken-ichi; Kumasaka Ryuichiro; Nakamura Masayuki; Shimada Michiko; Fujita Takeshi; Murakami Reiichi; Shimaya Yuko; Osawa Hiroshi; Yamabe Hideaki; Okumura Ken

2011-01-01

198

Antidepressant- and anxiolytic effects of the novel melatonin agonist Neu-P11 in rodent models  

Science.gov (United States)

Aim: To investigate the potential antidepressant and anxiolytic effects of Neu-P11, a novel melatonin agonist, in two models of depression in rats and a model of anxiety in mice. Methods: In the learned helplessness test (LH), Neu-P11 or melatonin (25–100 mg/kg, ip) was administered to rats 2 h before the beginning of the dark phase once a day for 5 days and the number of escape failures and intertrial crossings during the test phase were recorded. In the forced swimming test (FST), rats received a single or repeated administration of Neu-P11 (25–100 mg/kg, ip). The total period of immobility during the test phase was assessed. In the elevated plus-maze test (EPM), mice were treated with Neu-P11 (25–100 mg/kg, ip) or melatonin in the morning or in the evening and tested 2 h later. The percentage of time spent in the open arms and the open arms entries were assessed. Results: In the LH test, Neu-P11 but not melatonin significantly decreased the escape deficit and had no effect on the intertrial crossings. In the FST, a single or repeated administration of Neu-P11, either in the morning or in the evening, significantly decreased the duration of immobility. In the EPM test, Neu-P11 significantly increased the percentage of time spent in the open arms and the open arms entries irrespective to the time of administration. Melatonin was effective only when administered in the afternoon. Conclusion: The results demonstrate that Neu-P11 exerts antidepressant and anxiolytic activities in rodent models. PMID:20581849

Tian, Shao-wen; Laudon, Moshe; Han, Li; Gao, Jun; Huang, Fu-lian; Yang, Yu-feng; Deng, Hai-feng

2010-01-01

199

Melatonin  

Science.gov (United States)

... much sleepiness. Some of these sedative medications include clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan), and others.ModerateBe ... cause too much sleepiness. Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and ...

200

[Myocardial ischemia-reperfusion injury and melatonin].  

Science.gov (United States)

It is believed that myocardial ischemia-reperfusion injury is related to increased free radical generated and intracellular calcium overload especially during the period of reperfusion. The pineal secretory product, melatonin, is known to be a potent free radical scavenger, antioxidant and can inhibit the intracellular calcium overload. In this review, we have summarized the fundamental of cardiac ischemia-reperfusion injury and the effects of melatonin on myocardial damage that related to cardiac ischemia-reperfusion injury. The total antioxidant capacity of human serum is related to melatonin levels. Incidence of sudden cardiac death is high in the morning hours. It has been shown that melatonin levels are significantly low at these times and patients with coronary heart disease have lower than normal individuals. These findings thought that melatonin would be valuable to test in clinical trials for prevention of possible ischemia-reperfusion-induced injury, especially life threatening arrhythmias and infarct size, effecting life quality, associated with thrombolysis, angioplasty, coronary artery spasm or coronary bypass surgery. PMID:16766282

Sahna, Engin; Deniz, Esra; Aksulu, Hakki Engin

2006-06-01

 
 
 
 
201

Melatonin and the pathophysiology of cellular membranes  

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Full Text Available The ability of melatonin to influence the physiology of cell membranes is reviewed in this report. Publications related to this field from 1993 – present. Melatonin is a ubiquitously acting indoleamine which is associated with a variety of important functions within both unicellular and multicellular organisms. By virtue of its ability to protect lipids from free radical damage, melatonin is remarkably beneficial in preserving the morphological and functional integrity of cell membranes. In doing so, it reduces the quantity of oxidized lipids in membranes and maintains them at optimal fluidity, i.e., prevents them from becoming rigid. This contributes significantly to the function of proteins (receptors, channels, pores, etc. in the cell membranes and helps in preserving the normal physiology of the cells. In addition to these indirect effects of melatonin on membrane function, there is evidence that this indoleamine also may act directly on channels assisting membranes in maintaining proper ion gradients and current. The role of melatonin in the functioning of membrane channels and pores is an area of research that should be experimentally exploited.

Russel J. Reiter

2010-01-01

202

Aging and oxygen toxicity: Relation to changes in melatonin  

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Melatonin (N-acetyl-5-methoxytryptamine) is a chemical mediator produced in the pineal gland and other sites in the body. The melatonin found in the blood is derived almost exclusively from the pineal gland. Since the pineal synthesizes melatonin primarily at night, blood levels of the indole are also higher at night (5–15 fold) than during the day. Some individuals on a nightly basis produce twice as much melatonin as others of the same age. Throughout life, the melatonin rhythm gradually ...

Reiter, Russel J.

1997-01-01

203

Unlike the synchronous Plasmodium falciparum and P. chabaudi infection, the P. berghei and P. yoelii asynchronous infections are not affected by melatonin  

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Full Text Available Piero Bagnaresi1, Eduardo Alves1, Henrique Borges da Silva1, Sabrina Epiphanio2, Maria M Mota2, Célia RS Garcia11Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil; 2Unidade de Malária, Instituto de Medicina Molecular, Universidade de Lisboa, Lisboa, PortugalAbstract: We have previously reported that Plasmodium chabaudi and P. falciparum sense the hormone melatonin and this could be responsible for the synchrony of malaria infection. In P. chabaudi and P. falciparum, melatonin induces calcium release from internal stores, and this response is abolished by U73122, a phospholipase C inhibitor, and luzindole, a melatoninreceptor competitive antagonist. Here we show that, in vitro, melatonin is not able to modulate cell cycle, nor to elicit an elevation in intracellular calcium concentration of the intraerythrocytic forms of P. berghei or P. yoelii, two rodent parasites that show an asynchrononous development in vivo. Interestingly, melatonin and its receptor do not seem to play a role during hepatic infection by P. berghei sporozoites either. These data strengthen the hypothesis that hostderived melatonin does not synchronize malaria infection caused by P. berghei and P. yoelii. Moreover, these data explain why infections by these parasites are asynchronous, contrary to what is observed in P. falciparum and P. chabaudi infections.Keywords: malaria, calcium, melatonin, cell cycle, rhythm, sporozoite

Piero Bagnaresi

2009-04-01

204

Melatonin-induced neuroprotection after closed head injury is associated with increased brain antioxidants and attenuated late-phase activation of NF-kappaB and AP-1.  

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Traumatic brain injury (TBI) is followed by massive production of reactive oxygen species (ROS), which mediate secondary cellular damage. Low molecular weight antioxidants (LMWA) constitute one of the defense mechanisms of the brain, and their levels correlate with post-TBI outcome. Melatonin, the main pineal hormone, possesses antioxidant properties. We investigated the effects of melatonin on neurobehavioral recovery, brain LMWA, and activation of the redox-sensitive transcription factors nuclear factor-kappaB (NF-kappaB) and AP-1 in mice subjected to closed head injury (CHI). Given 1 h after CHI, melatonin facilitated recovery during at least 1 wk (P<0.05) and decreased lesion size by approximately twofold (P<0.01). The dose response displayed a bell-shape, i.e., neuroprotection was achieved with 5 but not 1 or 10 mg/kg. At the neuroprotective dose, melatonin treatment was associated with sustained (4 days) elevation of brain LMWA, including ascorbic acid (P<0.05). In contrast, LMWA were unaffected by the administration of the neuroprotective endocannabinoid 2-arachidonoyl glycerol. Furthermore, melatonin did not alter early phase (24 h) CHI-induced activation of NF-kappaB and AP-1; however, it blocked the robust late-phase (8 days) activation of NF-kappaB and decreased that of AP-1 to below basal levels. Our results demonstrate that melatonin induces neuroprotection, presumably via potentiation of brain antioxidants and attenuation of NF-kappaB and AP-1 activation. PMID:14597558

Beni, Sara M; Kohen, Ron; Reiter, Russel J; Tan, Dun-Xian; Shohami, Esther

2004-01-01

205

The role of melatonin as an antioxidant in the follicle.  

Science.gov (United States)

Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development. PMID:22277103

Tamura, Hiroshi; Takasaki, Akihisa; Taketani, Toshiaki; Tanabe, Manabu; Kizuka, Fumie; Lee, Lifa; Tamura, Isao; Maekawa, Ryo; Aasada, Hiromi; Yamagata, Yoshiaki; Sugino, Norihiro

2012-01-01

206

The role of melatonin as an antioxidant in the follicle  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Melatonin (N-acetyl-5-methoxytryptamine is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development.

Tamura Hiroshi

2012-01-01

207

Transcriptional Regulation of Programmed Hypertension by Melatonin: An Epigenetic Perspective  

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Full Text Available Melatonin is an endogenously produced indoleamine and secreted by the pineal gland. Melatonin has pleiotropic bioactivities and is involved in epigenetic regulation. Suboptimal conditions during maternal and perinatal phases can elicit epigenetic regulation of genes for nephrogenesis and reset physiological responses to develop programmed hypertension. This review discusses the early utility of melatonin to prevent programmed hypertension in later life by epigenetic regulation in the kidney, with an emphasis on: (1 the role of melatonin in epigenetic regulation; (2 the beneficial effects of melatonin on programmed hypertension; (3 epigenetic regulation of maternal melatonin therapy in different developmental windows of offspring kidneys analyzed by whole-genome RNA next-generation sequencing; and (4 current blocks in the application of melatonin in preventing programmed hypertension.

You-Lin Tain

2014-10-01

208

Vibrational and electronic spectroscopic studies of melatonin  

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We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm-1 regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except Nsbnd H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of Nsbnd H stretching is due to intermolecular interactions between melatonin molecules.

Singh, Gurpreet; Abbas, J. M.; Dogra, Sukh Dev; Sachdeva, Ritika; Rai, Bimal; Tripathi, S. K.; Prakash, Satya; Sathe, Vasant; Saini, G. S. S.

2014-01-01

209

Melatonin and its precursors scavenge nitric oxide  

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Nitric oxide (NO) scavenging activity of melatonin, N-acetyl-5-hydroxytryptamine, serotonin, 5-hydroxytryptophan and L-tryptophan was examined by the Griess reaction using flow injection analysis. 1-Hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene(NOC-7) was used as NO generator. The Griess reagent stoichiometrically reacts with NO2-, which was converted by a cadmium-copper reduction column from the stable end products of NO oxidation. Except for tryptophan, all the compounds examined scavenged NO in a dose-dependent manner. Melatonin, which has a methoxy group in the 5-position and an acetyl side chain, exhibited the most potent scavenging activity among the compounds tested. Serotonin, N-acetyl-5-hydroxytryptamine, and 5-hydroxytryptophan, respectively, showed moderate scavenging activity compared to melatonin. Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.

Noda, Y.; Mori, A.; Liburdy, R.; Packer, L.

1998-12-01

210

Melatonin protects against ionizing radiation-induced oxidative damage in corpus cavernosum and urinary bladder in rats.  

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The objective of this study was to examine the potential radioprotective properties of pharmacological doses of melatonin on corpus cavernosum and bladder tissues of whole-body irradiated (IR) rats. A total of 32 male Sprague-Dawley rats were exposed to irradiation performed with a LINAC which produced 6 MV photons at a focus 100 cm distant from the skin. Under ketamine anesthesia, each rat received a single whole-body dose of 800 cGy. Immediately before and after IR, rats were treated with either saline or melatonin (20 and 10 mg/kg, i.p.) and decapitated at 12 hr after exposure to irradiation. Another group of rats was followed for 72 hr after IR, where melatonin injections were repeated once daily. Tissue levels of malondialdehyde (MDA), an index of lipid peroxidation, and glutathione (GSH), a key antioxidant, were estimated in corpus cavernosum and urinary bladder. Tissues were also examined microscopically. The results demonstrate that both 12 and 72 hr following IR, tissue levels of MDA were elevated (P < 0.001), while GSH levels were reduced (P < 0.01) in both tissues. On the other hand, melatonin reversed these changes significantly (P < 0.05-0.01), concomitant with the improvement in histological appearances. Our results show that whole-body irradiation causes oxidative damage in the tissues of the genitourinary system. As melatonin administration reversed oxidative organ injury, as assessed by biochemical and histopathological findings, it is suggested that supplementing cancer patients with adjuvant therapy of melatonin may have some benefit for successful radiotherapy. PMID:15485549

Sener, Göksel; Atasoy, Beste M; Ersoy, Yasemin; Arbak, Serap; Sengöz, Meriç; Ye?en, Berrak C

2004-11-01

211

Linking Nocturnal Eddy Fluxes to Land Use-Land Cover in a Heterogeneous Landscape Surrounding the Urban-suburban Tower near Baltimore, Maryland  

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Anthropogenic activities in urban ecosystems represent the key driving force for local and regional climate change scenarios, producing the various pollutants that cause environmental change at the global scale: elevated carbon dioxide (CO2), increased ozone and nitrogen deposition, and elevated temperatures. Measurements of eddy fluxes in an urban-suburban landscape pose technical difficulties as sinks and sources of CO2 surrounding the tower are non-uniform. In a recent study, we stratified half-hourly values of eddy fluxes, i.e., carbon dioxide (Fco2), latent energy (LE), and sensible heat (H), according to wind sectors. Additionally, remotely sensed (spatial) data were stratified according to wind sectors around the Cub Hill tower near Baltimore, Maryland. We found that diurnal eddy fluxes were empirically dependent on remotely sensed metrics within the two-kilometer radius surrounding the tower. We hypothesized that nocturnal eddy fluxes, as stratified into wind sectors, will be similarly dependent on the land use-land cover (LULC). In the present study, we pooled the nocturnal half-hourly eddy fluxes during a 6-year period (2004-09) into a single data set, and stratified the data according to 24 wind sectors representing the wind direction during each half-hourly eddy flux measurement. We ask the following questions: 1) Are the nocturnal eddy fluxes inter-dependent with each other? 2) Do the average nocturnal eddy fluxes on a daily basis differ between wind sectors? 3) Which micrometeorological variables determine the differences in eddy fluxes between wind sectors? 4) Do differences in nocturnal eddy fluxes among wind sectors depend upon LULC? 5) Are the relationships between nocturnal eddy fluxes and LULC consistent during Winter, Spring, Summer, and Fall? and 6) How do these nocturnal urban-suburban eddy fluxes compare with the nocturnal eddy fluxes in a nearby mixed deciduous rural forest? Results from the data analyses will be presented and discussed.

Saliendra, N. Z.; Hom, J. L.; Pouyat, R.; Nowak, D.; Heisler, G. M.; Patterson, M.; Yesilonis, I.

2010-12-01

212

The research of melatonin in hypoxic-ischemic encephalopathy  

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Objective: To elucidate the function of melatonin in the pathogenesis and the prognosis of hypoxic-ischemic encephalopathy (HIE) and provide the pathophysiology basis for therapying HIE with melatonin. Methods: The level of plasma melatonin of twenty normal term infants and twenty modest HIE and twenty middle-severity HIE in their acute phase and recovery phase were assayed respectively with radioimmunoassay (RIA). Then compare the difference of the melatonin level among these neonates. Results: (1) For modest HIE, the melatonin level was higher than that in the normal in the acute phase and there was no difference to the normal in the recovery phase. (2) There was no difference between the melatonin level in middle-severity HIE in the acute phase and that in the normal, but in the recovery phase it was higher than that in the normal. (3) For modest HIE, the melatonin level in acute phase was higher than that in the recovery phase, but for middle-severity HIE, it was adverse. (4) In the acute phase, the level in modest HIE was higher than that in the middle-severity HIE, but on the contrary in the recovery phase. Conclusion: Melatonin have protection action on HIE. The prognosis of modest HIE neonates with rising melatonin level in the acute phase is better than that with lower melatonin level of middle-severity HIE. (authors)

213

Bat predation on nocturnally migrating birds  

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Bat predation on birds is a very rare phenomenon in nature. Most documented reports of bird-eating bats refer to tropical bats that occasionally capture resting birds. Millions of small birds concen- trate and cross over the world’s temperate regions during migra- tion, mainly at night, but no nocturnal predators are known to benefit from this enormous food resource. An analysis of 14,000 fecal pellets of the greater noctule bat (Nyctalus lasiopterus) reveals that this species captures...

Iba?n?ez, Carlos; Juste, Javier; Garci?a-mudarra, Juan L.; Agirre-mendi, Pablo T.

2001-01-01

214

Paroxysmal Nocturnal Hemoglobinuria from Bench to Bedside  

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Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disease that presents with protean manifestations. Clinical and laboratory investigation over the past 25 years have uncovered most of the basic science underpinnings of PNH and have led to the development of a highly effective targeted therapy. PNH originates from a multipotent hematopoietic stem cell (HSC) that acquires a somatic mutation in a gene called phosphatidylinositol glycan anchor biosynthesis, class A (PIG-A). The PIG...

Pu, Jeffrey J.; Brodsky, Robert A.

2011-01-01

215

How I treat paroxysmal nocturnal hemoglobinuria  

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Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal blood disorder that manifests with hemolytic anemia, bone marrow failure, and thrombosis. Many of the clinical manifestations of the disease result from complement-mediated intravascular hemolysis. Allogeneic bone marrow transplantation is the only curative therapy for PNH. Eculizumab, a monoclonal antibody that blocks terminal complement activation, is highly effective in reducing hemolysis, improving quality of life, and reducing th...

Brodsky, Robert A.

2009-01-01

216

Nocturnal oxygen desaturation in coronary artery disease.  

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Nocturnal oxygen desaturation and sleep apnea may provoke myocardial ischemia and arrhythmias in patients with coronary artery disease (CAD). Additionally, these factors may accelerate coronary atherosclerosis in the long term and they may play a role in the progression of the disease process. On the other hand, studies related to this subject are limited. This study was conducted to investigate the nocturnal oxygen desaturation and apneas during sleep in patients with CAD and to assess the possible association of these factors with CAD. We studied 22 male patients with CAD confirmed by coronary angiography who did not have symptomatic pulmonary disease and fourteen male healthy controls without known heart disease. Patients were randomly selected from men undergoing coronary angiography. Controls were age and sex matched and selected from the population registry. The normal controls were of similar body mass index to the patients. None of them were obese. The patients and controls underwent standard polysomnography. Men with CAD and controls had a similar apnea-hypopnea index (2.3 +/- 3.8 vs. 1.2 +/- 1.7). Mean oxygen desaturation index was higher among patients than controls (2.1 vs. 0.5, p breathing, in particular nocturnal oxygen desaturation, occurs more common in patients with CAD compared to controls. Additionally, patients are at higher risk of developing bradycardia during sleep. This findings suggest that oxygen desaturation during sleep might contribute to the progression of CAD. PMID:10370394

Cilli, A; Tatlicio?lu, T; Köktürk, O

1999-01-01

217

Ebola virus disease: potential use of melatonin as a treatment.  

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The purpose of this report is to emphasize the potential utility for the use of melatonin in the treatment of individuals who are infected with the Ebola virus. The pathological changes associated with an Ebola infection include, most notably, endothelial disruption, disseminated intravascular coagulation and multiple organ hemorrhage. Melatonin has been shown to target these alterations. Numerous similarities between Ebola virus infection and septic shock have been recognized for more than a decade. Moreover, melatonin has been successfully employed for the treatment of sepsis in many experimental and clinical studies. Based on these factors, as the number of treatments currently available is limited and the useable products are not abundant, the use of melatonin for the treatment of Ebola virus infection is encouraged. Additionally, melatonin has a high safety profile, is readily available and can be orally self-administered; thus, the use of melatonin is compatible with the large scale of this serious outbreak. PMID:25262626

Tan, Dun-Xian; Korkmaz, Ahmet; Reiter, Russel J; Manchester, Lucien C

2014-11-01

218

Daily rhythms of plasma melatonin, but not plasma leptin or leptin mRNA, vary between lean, obese and type 2 diabetic men.  

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Melatonin and leptin exhibit daily rhythms that may contribute towards changes in metabolic physiology. It remains unclear, however, whether this rhythmicity is altered in obesity or type 2 diabetes (T2DM). We tested the hypothesis that 24-hour profiles of melatonin, leptin and leptin mRNA are altered by metabolic status in laboratory conditions. Men between 45-65 years old were recruited into lean, obese-non-diabetic or obese-T2DM groups. Volunteers followed strict sleep-wake and dietary regimes for 1 week before the laboratory study. They were then maintained in controlled light-dark conditions, semi-recumbent posture and fed hourly iso-energetic drinks during wake periods. Hourly blood samples were collected for hormone analysis. Subcutaneous adipose biopsies were collected 6-hourly for gene expression analysis. Although there was no effect of subject group on the timing of dim light melatonin onset (DLMO), nocturnal plasma melatonin concentration was significantly higher in obese-non-diabetic subjects compared to weight-matched T2DM subjects (p<0.01) and lean controls (p<0.05). Two T2DM subjects failed to produce any detectable melatonin, although did exhibit plasma cortisol rhythms comparable to others in the group. Consistent with the literature, there was a significant (p<0.001) effect of subject group on absolute plasma leptin concentration and, when expressed relative to an individual's 24-hour mean, plasma leptin showed significant (p<0.001) diurnal variation. However, there was no difference in amplitude or timing of leptin rhythms between experimental groups. There was also no significant effect of time on leptin mRNA expression. Despite an overall effect (p<0.05) of experimental group, post-hoc analysis revealed no significant pair-wise effects of group on leptin mRNA expression. Altered plasma melatonin rhythms in weight-matched T2DM and non-diabetic individuals supports a possible role of melatonin in T2DM aetiology. However, neither obesity nor T2DM changed 24-hour rhythms of plasma leptin relative to cycle mean, or expression of subcutaneous adipose leptin gene expression, compared with lean subjects. PMID:22623983

Mäntele, Simone; Otway, Daniella T; Middleton, Benita; Bretschneider, Silvia; Wright, John; Robertson, M Denise; Skene, Debra J; Johnston, Jonathan D

2012-01-01

219

Protective effect of melatonin on thrombocytopoiesis in irratiated mice  

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the melatonin concentration was 200 nmol/L. Conclusion: Melatonin provides protective effect on T in irradiated mice. It enhances T in vivo and promotes the growth of bone marrow stromal cells as well as megakaryocytes in vitro. Therefore, we speculate that the T-protective activity of melatonin may be mediated via promoting growth of the progenitors of platelet, megakaryocytes, and bone marrow stromal cells. (authors)

220

Oxytocin and prolactin release after hypertonic saline administration in melatonin-treated male Syrian hamsters  

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The aim of the present investigations was to examine the effects of melatonin (Mel) on oxytocin (OT) release under conditions of osmotic stimulation, brought about by hypertonic saline administration, as well as to determine whether osmotically stimulated OT release in Mel-treated Syrian hamster is associated with alterations in the release of prolactin (PRL) and in norepinephrine (NE) and dopamine (DA) content in the hypothalamus. In both Mel- and vehicle-treated hamsters, injection of hypertonic saline was followed by a significant decrease in OT content in the pituitary neurointermediate lobe (NIL) and elevation of plasma OT and PRL levels. Melatonin injections had no significant affect on NIL OT content in either isotonic- or hypertonic-saline treated animals. Pretreatment with Mel did not alter plasma OT or PRL levels in isotonic saline-injected animals. However, Mel facilitated the release of OT, but prevented the release of PRL after hypertonic saline administration. Melatonin treatment reduced hypothalamic NE content (but not that of DA) in isotonic-saline treated animals. After osmotic stimulation, hypothalamic content of NE and DA was significantly lower in Mel-treated than in vehicle-treated animals. Data from the present study suggest that the osmotically-stimulated release of OT and PRL seems to be related to the activation of noradrenergic rather than dopaminergic transmission. Both dopaminergic and noradrenergic transmission may be, however, involved in mediating the effects of Mel on the osmotically-activated OT and PRL release. (author). 48 refs, 3 figs

 
 
 
 
221

Oxytocin and prolactin release after hypertonic saline administration in melatonin-treated male Syrian hamsters  

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The aim of the present investigations was to examine the effects of melatonin (Mel) on oxytocin (OT) release under conditions of osmotic stimulation, brought about by hypertonic saline administration, as well as to determine whether osmotically stimulated OT release in Mel-treated Syrian hamster is associated with alterations in the release of prolactin (PRL) and in norepinephrine (NE) and dopamine (DA) content in the hypothalamus. In both Mel- and vehicle-treated hamsters, injection of hypertonic saline was followed by a significant decrease in OT content in the pituitary neurointermediate lobe (NIL) and elevation of plasma OT and PRL levels. Melatonin injections had no significant affect on NIL OT content in either isotonic- or hypertonic-saline treated animals. Pretreatment with Mel did not alter plasma OT or PRL levels in isotonic saline-injected animals. However, Mel facilitated the release of OT, but prevented the release of PRL after hypertonic saline administration. Melatonin treatment reduced hypothalamic NE content (but not that of DA) in isotonic-saline treated animals. After osmotic stimulation, hypothalamic content of NE and DA was significantly lower in Mel-treated than in vehicle-treated animals. Data from the present study suggest that the osmotically-stimulated release of OT and PRL seems to be related to the activation of noradrenergic rather than dopaminergic transmission. Both dopaminergic and noradrenergic transmission may be, however, involved in mediating the effects of Mel on the osmotically-activated OT and PRL release. (author). 48 refs, 3 figs.

Juszczak, M.; Steger, R.W.; Fadden, C.; Bartke, A. [Southern Illinois Univ., Carbondale, IL (United States)

1996-12-31

222

Melatonin protects against behavioural dysfunctions and dendritic spine damage in 3-nitropropionic acid-induced rat model of Huntington's disease.  

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Huntington's disease (HD), an autosomal dominant neurodegenerative movement disorder in which striatal and cortical neurons are mostly affected, has no effective cure existing. A fungal neurotoxin and a potent inhibitor of mitochondrial electron transport chain complex II inhibitor, 3-nitropropionic acid (3-NP) is known to cause HD pathology, including lesions in the striatum and the cortex, and several behavioural syndromes in experimental animals. In the present study we examined the effect of melatonin on motor activities, neuronal morphology as revealed by Nissl and rapid Golgi staining, as well as GABA, glutamate and biogenic amine neurotransmitter levels in 3-NP-induced HD in rats. We found that melatonin (10, 20mg/kg, i.p.) administered 1h prior to 3-NP dose (20mg/kg; daily for 4 days) restored motor coordination ability as shown in gait, beam balancing, swim ability and performance on rotarod. However it failed to reduce 3-NP-induced striatal lesion core area, neuronal damage and the elevated levels of striatal dopamine. Melatonin administration partially restored 3-NP-induced loss of dendritic spines in the striatum and the cortex, and the reduction in cerebellar granule cell, but not hippocampal CA1 neuronal arborization. These findings collectively suggest that melatonin offers beneficial effects in correction of learning related fine motor adjustments, but not in behaviours unrelated to learning, by the restoration of striatal and cortical spines, and cerebellar granule cell arborization. PMID:24509309

Chakraborty, J; Nthenge-Ngumbau, D N; Rajamma, U; Mohanakumar, K P

2014-05-01

223

Rat liver mitochondrial damage under acute or chronic carbon tetrachloride-induced intoxication: Protection by melatonin and cranberry flavonoids  

International Nuclear Information System (INIS)

In current societies, the risk of toxic liver damage has markedly increased. The aim of the present work was to carry out further research into the mechanism(s) of liver mitochondrial damage induced by acute (0.8 g/kg body weight, single injection) or chronic (1.6 g/ kg body weight, 30 days, biweekly injections) carbon tetrachloride – induced intoxication and to evaluate the hepatoprotective potential of the antioxidant, melatonin, as well as succinate and cranberry flavonoids in rats. Acute intoxication resulted in considerable impairment of mitochondrial respiratory parameters in the liver. The activity of mitochondrial succinate dehydrogenase (complex II) decreased (by 25%, p 4 displayed obvious irreversible impairments. Long-term melatonin administration (10 mg/kg, 30 days, daily) to chronically intoxicated rats diminished the toxic effects of CCl4, reducing elevated plasma activities of alanine aminotransferase and aspartate aminotransferase and bilirubin concentration, prevented accumulation of membrane lipid peroxidation products in rat liver and resulted in apparent preservation of the mitochondrial ultrastructure. The treatment of the animals by the complex of melatonin (10 mg/kg) plus succinate (50 mg/kg) plus cranberry flavonoids (7 mg/kg) was even more effective in prevention of toxic liver injury and liver mitochondria damage. Highlights: ? After 30-day chronic CCl4 intoxication mitochondria displayed considerable changes. ? The functional parameters of mitochondria were similar to the control values. ? Melatonin + succinate + flavonoids prevented mitochondrial ultrastructure damage. ? The above complex enhanced regenerative processes in the liver.

224

Melatonin and its use in atherosclerosis and dyslipidemia  

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Full Text Available Konstantin V Danilenko, Yulia I Ragino Institute of Internal Medicine, Siberian Branch of the Russian Academy of Medical Sciences, Novosibirsk, Russia Abstract: A review of pineal melatonin synthesis, regulation, and physiological effects indicates that not only does melatonin act as a hormonal signal of darkness, but also that it possesses antioxidant and anti-inflammatory properties. Although oxidation and inflammation play a pivotal role in atherogenesis, no studies have investigated administration of melatonin for human arterial atherosclerosis. However, 13 clinical trials have investigated use of melatonin in dyslipidemia, which is a close correlate of atherosclerosis. The results of these clinical trials, particularly the five that are placebo-controlled, are inconclusive as to whether melatonin can normalize the blood lipid profile. Significant confounders in these studies might be a phase shift of the cholesterol rhythm by melatonin, a posture effect at venipuncture, uncontrolled diet during the course of melatonin intake, and the phenomenon of regression to the mean. Thus, future studies are required, which should also consider use of higher doses of melatonin and/or measurement of oxidized forms of cholesterol-containing particles (which are the most aggressive in relation to atherogenesis in addition to lipidic fractions. Keywords: melatonin, serum lipids, atherosclerosis, clinical trials

Danilenko KV

2013-03-01

225

Detection of melatonin receptor mRNA in human muscle  

International Nuclear Information System (INIS)

To verify the expression of melatonin receptor mRNA in human, muscle, muscle beside vertebrae was collected to obtain total RNA and the mRNA of melatonin receptor was detected by RT-PCR method. The electrophoretic results of RT-PCR products by mt1 and MT2 primer were all positive and the sequence is corresponding with human melatonin receptor cDNA. It suggests that melatonin may act on the muscle beside vertebrae directly and regulate its growth and development. (authors)

226

Melatonin, a potential effective protector in whole body ?-irradiated rats  

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Melatonin (N-acetyl-5-methoxytryptamine), the chief hormone of pineal gland, is widely distributed in animal kingdom. It is claimed for its antioxidant and free radical properties. The present study aimed to examine the radio protective potentiality and efficacy of melatonin against damages induced in whole body ?-irradiated rats. Animals received melatonin (10 mg/ kg body wt/ day) for 10 successive days pre-exposure to 3 Gy of ?-radiation (acute dose). Rats sacrificed at 10 and 20 days post the irradiation time. The results revealed that the prolonged administration of melatonin has ameliorated the radiation- induced depletion in brain, testis and serum glutathione (GSH) level and a decrease in serum glutathione peroxidase (GPX) activity when compared with their matched values in irradiated rats. In addition, remarkable decreases in the concentration of lipid peroxidation (LPO) product; malondialdhyde (MDA) was observed in brain, testis and serum of rats received melatonin pre-radiation exposure. As well as, significant decreases in disulphide glutathione (GSSG) were observed in serum.Histopathological examination of brain and testis showed that administration of melatonin pre-irradiation according to the present regimen has attenuated radiation induced tissue damages and improved tissue architecture. Cytogenetically, the chromosomal aberration (CA) assay in bone marrow pointed out a significant difference between rats received melatonin pre-irradiation and ?-irraed melatonin pre-irradiation and ?-irradiated rats in most CA types. Accordingly, it could be postulated the tissue diversity and cytogenetic impact of the administrated melatonin against acute ion syndrome in rat model.

227

Melatonin for the treatment of irritable bowel syndrome.  

Science.gov (United States)

Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain or discomfort, in combination with disturbed bowel habits in the absence of identifiable organic cause. Melatonin (N-acetyl-5-methoxytryptamine) is a hormone produced by the pineal gland and also large number by enterochromaffin cells of the digestive mucosa. Melatonin plays an important part in gastrointestinal physiology which includes regulation of gastrointestinal motility, local anti-inflammatory reaction as well as moderation of visceral sensation. Melatonin is commonly given orally. It is categorized by the United States Food and Drug Administration as a dietary supplement. Melatonin treatment has an extremely wide margin of safety though it may cause minor adverse effects, such as headache, rash and nightmares. Melatonin was touted as a potential effective candidate for IBS treatment. Putative role of melatonin in IBS treatment include analgesic effects, regulator of gastrointestinal motility and sensation to sleep promoter. Placebo-controlled studies in melatonin suffered from heterogeneity in methodology. Most studies utilized 3 mg at bedtime as the standard dose of trial. However, all studies had consistently showed improvement in abdominal pain, some showed improvement in quality of life of IBS patients. Melatonin is a relatively safe drug that possesses potential in treating IBS. Future studies should focus on melatonin effect on gut mobility as well as its central nervous system effect to elucidate its role in IBS patients. PMID:24627586

Siah, Kewin Tien Ho; Wong, Reuben Kong Min; Ho, Khek Yu

2014-03-14

228

Melatonin Effects on Hard Tissues: Bone and Tooth  

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Full Text Available Melatonin is an endogenous hormone rhythmically produced in the pineal gland under the control of the suprachiasmatic nucleus (SCN and the light/dark cycle. This indole plays an important role in many physiological processes including circadian entrainment, blood pressure regulation, seasonal reproduction, ovarian physiology, immune function, etc. Recently, the investigation and applications of melatonin in the hard tissues bone and tooth have received great attention. Melatonin has been investigated relative to bone remolding, osteoporosis, osseointegration of dental implants and dentine formation. In the present review, we discuss the large body of published evidence and review data of melatonin effects on hard tissues, specifically, bone and tooth.

Hong-Wen He

2013-05-01

229

Maternal and placental melatonin: actions and implication for successful pregnancies.  

Science.gov (United States)

Melatonin is one of the main sources of mitochondrial protection and its protective effects are equal or even better if compared with several consecrated antioxidants. Furthermore, the activation of specific melatonin receptors triggers several cellular pathways that improve the oxidoreduction and inflammatory cellular state. The discovery of the melatoninergic machinery in placental cells was the first step to understand the effects of this indoleamine during pregnancy. In critical points of pregnancy, melatonin has been pointed as a protagonist and its beneficial effects have been shown as essential for the control of trophoblastic function and development. On the contrary of the plasmatic melatonin (produced in pineal gland), placental melatonin does not vary according to the circadian cycle and acts as an autocrine, paracrine, intracrine, and endocrine hormone. The important effects of melatonin in placenta have been demonstrated in the physiopathology of pre-eclampsia with alterations in the levels of melatonin and in the expression of its receptors and synthetizing enzymes. Some authors suggested melatonin as a biomarker of pre-eclampsia and as a possible treatment for this disease and other obstetric pathologies associated with placental defect and increases in oxidative stress. This review will approach the beneficial effects of melatonin on placenta homeostasis and consequently on pregnancy and fetal health. PMID:24971781

Sagrillo-Fagundes, L; Soliman, A; Vaillancourt, C

2014-06-01

230

Melatonin regulates proteomic changes during leaf senescence in Malus hupehensis.  

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Despite the relationship between melatonin and aging, the overall changes and regulation of proteome profiling by long-term melatonin exposure during leaf senescence is not well understood. In this study, leaf senescence in Malus hupehensis plants was delayed when exogenous melatonin was regularly applied to the roots for 2 months compared with natural leaf senescence. Proteins of samples 0 and 50 day for both treatments were extracted and labeled with TMT regents before being examined via NanoLC-MS/MS. The proteomics data showed that 622 and 309 proteins were altered by senescence and melatonin, respectively. Our GO analysis by Blast2GO revealed that most of the altered proteins that are involved in major metabolic processes exhibited hydrolase activity and were mainly located in the plastids. These proteins were classified into several senescence-related functional categories, including degradation of macromolecules, redox and stress responses, transport, photosynthesis, development, and other regulatory proteins. We found that melatonin treatment led to the downregulation of proteins that are normally upregulated during senescence. The melatonin-related delay in senescence might have occurred due to the altering of proteins involved in processes associated with senescence. And as well, there are many unknown regulatory proteins possibly being involved in the melatonin's function. This study is the first to demonstrate changes at the proteome level in response to exogenous melatonin in plants. Our findings provide a set of informative and fundamental data about the role of melatonin in apple leaf senescence. PMID:25146528

Wang, Ping; Sun, Xun; Xie, Yinpeng; Li, Mingjun; Chen, Wei; Zhang, Sheng; Liang, Dong; Ma, Fengwang

2014-10-01

231

Effect of laser acupuncture for monosymptomatic nocturnal enuresis on bladder reservoir function and nocturnal urine output  

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The alternative treatments for enuresis have been reported with high efficacy but in noncontrolled studies. Therefore, using a prospective, single-blind, randomized, placebo controlled design we evaluated the effect of laser acupuncture on bladder reservoir function and enuresis frequency in cases of monosymptomatic nocturnal enuresis with reduced maximal voided volume.

Radvanska, E; Kamperis, Konstantinos

2011-01-01

232

Exposure to 2500 lux increases serum melatonin in Venezuelan equine encephalomyelitis.  

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When mice infected with the Venezuelan equine encephalomyelitis (VEE) virus were exposed to 2500 lux with a 12 h light: 12 h dark photoperiod, the serum levels of melatonin (MLT) remained constantly elevated. In mice exposed to 400 lux low levels of serum MLT were detected during the day and high levels during the night. An increase in the survival rate of the infected mice from 6 to 13 days after virus inoculation was also observed. The significant increment in the concentration of serum MLT produced by the high intensity light could be responsible for the longer survival rate of mice infected with the VEE virus. PMID:10447461

Medina, S; Valero-Fuenmayor, N; Chacín-Bonilla, L; Añez, F; Giraldoth, D; Arias, J; Espina, G; Achong, A Y; Bonilla, E

1999-06-01

233

Melatonin in Alzheimer's disease and other neurodegenerative disorders  

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Full Text Available Abstract Increased oxidative stress and mitochondrial dysfunction have been identified as common pathophysiological phenomena associated with neurodegenerative disorders such as Alzheimer's disease (AD, Parkinson's disease (PD and Huntington's disease (HD. As the age-related decline in the production of melatonin may contribute to increased levels of oxidative stress in the elderly, the role of this neuroprotective agent is attracting increasing attention. Melatonin has multiple actions as a regulator of antioxidant and prooxidant enzymes, radical scavenger and antagonist of mitochondrial radical formation. The ability of melatonin and its kynuramine metabolites to interact directly with the electron transport chain by increasing the electron flow and reducing electron leakage are unique features by which melatonin is able to increase the survival of neurons under enhanced oxidative stress. Moreover, antifibrillogenic actions have been demonstrated in vitro, also in the presence of profibrillogenic apoE4 or apoE3, and in vivo, in a transgenic mouse model. Amyloid-? toxicity is antagonized by melatonin and one of its kynuramine metabolites. Cytoskeletal disorganization and protein hyperphosphorylation, as induced in several cell-line models, have been attenuated by melatonin, effects comprising stress kinase downregulation and extending to neurotrophin expression. Various experimental models of AD, PD and HD indicate the usefulness of melatonin in antagonizing disease progression and/or mitigating some of the symptoms. Melatonin secretion has been found to be altered in AD and PD. Attempts to compensate for age- and disease-dependent melatonin deficiency have shown that administration of this compound can improve sleep efficiency in AD and PD and, to some extent, cognitive function in AD patients. Exogenous melatonin has also been reported to alleviate behavioral symptoms such as sundowning. Taken together, these findings suggest that melatonin, its analogues and kynuric metabolites may have potential value in prevention and treatment of AD and other neurodegenerative disorders.

Poeggeler B

2006-05-01

234

Expression of melatonin receptors in arteries involved in thermoregulation  

International Nuclear Information System (INIS)

Melatonin binding sites were localized and characterized in the vasculature of the rat by using the melatonin analogue 2-[125I]iodomelatonin (125I-melatonin) and quantitative in vitro autoradiography. The expression of these sites was restricted to the caudal artery and to the arteries that form the circle of Willis at the base of the brain. The arterial 125I-melatonin binding was stable, saturable, and reversible. Saturation studies revealed that the binding represented a single class of high-affinity binding sites with a dissociation constant (Kd) of 3.4 x 10(-11) M in the anterior cerebral artery and 1.05 x 10(-10) M in the caudal artery. The binding capacities (Bmax) in these arteries were 19 and 15 fmol/mg of protein, respectively. The relative order of potency of indoles for inhibition of 125I-melatonin binding at these sites was typical of a melatonin receptor: 2-iodomelatonin greater than melatonin greater than N-acetylserotonin much much greater than 5-hydroxytryptamine. Norepinephrine-induced contraction of the caudal artery in vitro was significantly prolonged and potentiated by melatonin in a concentration-dependent manner, suggesting that these arterial binding sites are functional melatonin receptors. Neither primary steps in smooth muscle contraction (inositol phospholipid hydrolysis) nor relaxation (adenylate cyclase activation) were affected by melatonin. Melatonin, through its action on the tone of these arteries, may cause circulatory adjustments inries, may cause circulatory adjustments in these arteries, which are believed to be involved in thermoregulation

235

Melatonin synthesis: 14-3-3-dependent activation and inhibition of arylalkylamine N-acetyltransferase mediated by phosphoserine-205  

Science.gov (United States)

The nocturnal increase in circulating melatonin in vertebrates is regulated by the activity of arylalkylamine N-acetyltransferase (AANAT), the penultimate enzyme in the melatonin pathway (serotonin ? N-acetylserotonin ? melatonin). Large changes in activity are linked to cyclic AMP-dependent protein kinase-mediated phosphorylation of AANAT T31. Phosphorylation of T31 promotes binding of AANAT to the dimeric 14-3-3 protein, which activates AANAT by increasing arylalkylamine affinity. In the current study, a putative second AANAT cyclic AMP-dependent protein kinase phosphorylation site, S205, was found to be ?55% phosphorylated at night, when T31 is ?40% phosphorylated. These findings indicate that ovine AANAT is dual-phosphorylated. Moreover, light exposure at night decreases T31 and S205 phosphorylation, consistent with a regulatory role of both sites. AANAT peptides containing either T31 or S205 associate with 14-3-3? in a phosphorylation-dependent manner; binding through phosphorylated (p)T31 is stronger than that through pS205, consistent with the location of only pT31 in a mode I binding motif, one of two recognized high-affinity 14-3-3-binding motifs AANAT protein binds to 14-3-3? through pT31 or pS205. Two-site binding lowers the Km for arylalkylamine substrate to ?30 ?M. In contrast, single-site pS205 binding increases the Km to ?1,200 ?M. Accordingly, the switch from dual to single pS205 binding of AANAT to 14-3-3 changes the Km for substrates by ?40-fold. pS205 seems to be part of a previously unrecognized 14-3-3-binding motif-pS/pT (X1–2)-COOH, referred to here as mode III. PMID:15644438

Ganguly, Surajit; Weller, Joan L.; Ho, Anthony; Chemineau, Philippe; Malpaux, Benoit; Klein, David C.

2005-01-01

236

Paroxysmal nocturnal hemoglobinuria presenting as moyamoya syndrome.  

Science.gov (United States)

We report an 11-year-old girl who has paroxysmal nocturnal hemoglobinuria (PNH) and was admitted because of recurrent cerebrovascular accidents (CVA) and intermittent hemoglobinuria. Internal carotid angiography revealed bilateral typical moyamoya patterns. Although CVA due to arterial thrombosis may occur in PNH, the basal moyamoya vessels were never mentioned in case reports yet. The moyamoya syndrome has been reported in a variety of diseases and represents the nonspecific response to an impairment of arterial flow at specific sites in the brain. Our case discloses that PNH may present as moyamoya syndrome. PMID:8733912

Lin, H C; Chen, R L; Wang, P J

1996-01-01

237

Microorganisms for the production of melatonin  

DEFF Research Database (Denmark)

Recombinant microbial cells and methods for producing melatonin and related compounds using such cells are described. More specifically, the recombinant microbial cell may comprise exogenous genes encoding one or more of an L-tryptophan hydroxylase, a 5-hydroxy-L- tryptophan decarboxylyase, a serotonin acetyltransferase, an acetylserotonin O- methyltransferase; an L-tryptophan decarboxy-lyase, and a tryptamine-5-hydroxylase, and means for providing tetrahydrobiopterin (THB). Related sequences and vectors for use in preparing such recombinant microbial cells are also described.

Knight, Eric Michael Technical University of Denmark,

238

The impact of nocturnal hemodialysis on sexual function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Sexual dysfunction is common in patients with end stage renal disease (ESRD) and treatment options are limited. Observational studies suggest that nocturnal hemodialysis may improve sexual function. We compared sexual activity and responses to sexual related questions in the Kidney Disease Quality of Life Short Form questionnaire among patients randomized to frequent nocturnal or thrice weekly conventional hemodialysis. Methods We performed a...

Bass Adam; Ahmed Sofia B; Klarenbach Scott; Culleton Bruce; Hemmelgarn Brenda R; Manns Braden

2012-01-01

239

Cold air drainage and modeled nocturnal leaf water potential in complex forested terrain.  

Science.gov (United States)

Spatial variation in microclimate caused by air temperature inversions plays an important role in determining the timing and rate of many physical and biophysical processes. Such phenomena are of particular interest in mountainous regions where complex physiographic terrain can greatly complicate these processes. Recent work has demonstrated that, in some plants, stomata do not close completely at night, resulting in nocturnal transpiration. The following work was undertaken to develop a better understanding of nocturnal cold air drainage and its subsequent impact on the reliability of predawn leaf water potential (Psi(pd)) as a surrogate for soil water potential (Psi(s)). Eight temperature data loggers were installed on a transect spanning a vertical distance of 155 m along a north facing slope in the Mica Creek Experimental Watershed (MCEW) in northern Idaho during July and August 2004. Results indicated strong nocturnal temperature inversions occurring from the low- to upper-mid-slope, typically spanning the lower 88 m of the vertical distance. Based on mean temperatures for both months, inversions resulted in lapse rates of 29.0, 27.0 and 25.0 degrees C km(-1) at 0000, 0400 and 2000 h, respectively. At this scale (i.e., water potential. As a result of cold air drainage, modeled Psi(pd) became consistently more negative (up to -0.3 MPa) at higher elevations during the night based on mean temperatures. Nocturnal inversions on the lower- and mid-slopes resulted in leaf water potentials that were at least 30 and 50% more negative over the lower 88 m of the inversion layer, based on mean and maximum temperatures, respectively. However, on a cloudy night, with low D, the maximum decrease in Psi(pd) was -0.04 MPa. Our results indicate that, given persistent cold air drainage and nighttime stomatal opening, serious errors will result if Psi(s) is estimated from Psi(pd). PMID:17242004

Hubbart, Jason A; Kavanagh, Kathleen L; Pangle, Robert; Link, Tim; Schotzko, Alisa

2007-04-01

240

Fundamental Issues Related to the Origin of Melatonin and Melatonin Isomers during Evolution: Relation to Their Biological Functions  

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Melatonin and melatonin isomers exist and/or coexist in living organisms including yeasts, bacteria and plants. The levels of melatonin isomers are significantly higher than that of melatonin in some plants and in several fermented products such as in wine and bread. Currently, there are no reports documenting the presence of melatonin isomers in vertebrates. From an evolutionary point of view, it is unlikely that melatonin isomers do not exist in vertebrates. On the other hand, large quantities of the microbial flora exist in the gut of the vertebrates. These microorganisms frequently exchange materials with the host. Melatonin isomers, which are produced by these organisms inevitably enter the host’s system. The origins of melatonin and its isomers can be traced back to photosynthetic bacteria and other primitive unicellular organisms. Since some of these bacteria are believed to be the precursors of mitochondria and chloroplasts these cellular organelles may be the primary sites of melatonin production in animals or in plants, respectively. Phylogenic analysis based on its rate-limiting synthetic enzyme, serotonin N-acetyltransferase (SNAT), indicates its multiple origins during evolution. Therefore, it is likely that melatonin and its isomer are also present in the domain of archaea, which perhaps require these molecules to protect them against hostile environments including extremely high or low temperature. Evidence indicates that the initial and primary function of melatonin and its isomers was to serve as the first-line of defence against oxidative stress and all other functions were acquired during evolution either by the process of adoption or by the extension of its antioxidative capacity. PMID:25207599

Tan, Dun-Xian; Zheng, Xiaodong; Kong, Jin; Manchester, Lucien C.; Hardeland, Ruediger; Kim, Seok Joong; Xu, Xiaoying; Reiter, Russel J.

2014-01-01

 
 
 
 
241

Fundamental Issues Related to the Origin of Melatonin and Melatonin Isomers during Evolution: Relation to Their Biological Functions  

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Full Text Available Melatonin and melatonin isomers exist and/or coexist in living organisms including yeasts, bacteria and plants. The levels of melatonin isomers are significantly higher than that of melatonin in some plants and in several fermented products such as in wine and bread. Currently, there are no reports documenting the presence of melatonin isomers in vertebrates. From an evolutionary point of view, it is unlikely that melatonin isomers do not exist in vertebrates. On the other hand, large quantities of the microbial flora exist in the gut of the vertebrates. These microorganisms frequently exchange materials with the host. Melatonin isomers, which are produced by these organisms inevitably enter the host’s system. The origins of melatonin and its isomers can be traced back to photosynthetic bacteria and other primitive unicellular organisms. Since some of these bacteria are believed to be the precursors of mitochondria and chloroplasts these cellular organelles may be the primary sites of melatonin production in animals or in plants, respectively. Phylogenic analysis based on its rate-limiting synthetic enzyme, serotonin N-acetyltransferase (SNAT, indicates its multiple origins during evolution. Therefore, it is likely that melatonin and its isomer are also present in the domain of archaea, which perhaps require these molecules to protect them against hostile environments including extremely high or low temperature. Evidence indicates that the initial and primary function of melatonin and its isomers was to serve as the first-line of defence against oxidative stress and all other functions were acquired during evolution either by the process of adoption or by the extension of its antioxidative capacity.

Dun-Xian Tan

2014-09-01

242

Fundamental issues related to the origin of melatonin and melatonin isomers during evolution: relation to their biological functions.  

Science.gov (United States)

Melatonin and melatonin isomers exist and/or coexist in living organisms including yeasts, bacteria and plants. The levels of melatonin isomers are significantly higher than that of melatonin in some plants and in several fermented products such as in wine and bread. Currently, there are no reports documenting the presence of melatonin isomers in vertebrates. From an evolutionary point of view, it is unlikely that melatonin isomers do not exist in vertebrates. On the other hand, large quantities of the microbial flora exist in the gut of the vertebrates. These microorganisms frequently exchange materials with the host. Melatonin isomers, which are produced by these organisms inevitably enter the host's system. The origins of melatonin and its isomers can be traced back to photosynthetic bacteria and other primitive unicellular organisms. Since some of these bacteria are believed to be the precursors of mitochondria and chloroplasts these cellular organelles may be the primary sites of melatonin production in animals or in plants, respectively. Phylogenic analysis based on its rate-limiting synthetic enzyme, serotonin N-acetyltransferase (SNAT), indicates its multiple origins during evolution. Therefore, it is likely that melatonin and its isomer are also present in the domain of archaea, which perhaps require these molecules to protect them against hostile environments including extremely high or low temperature. Evidence indicates that the initial and primary function of melatonin and its isomers was to serve as the first-line of defence against oxidative stress and all other functions were acquired during evolution either by the process of adoption or by the extension of its antioxidative capacity. PMID:25207599

Tan, Dun-Xian; Zheng, Xiaodong; Kong, Jin; Manchester, Lucien C; Hardeland, Ruediger; Kim, Seok Joong; Xu, Xiaoying; Reiter, Russel J

2014-01-01

243

Renal clearance of melatonin Renale opruiming van melatonien  

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Full Text Available Only two publications exist in which actual values for the renal clearance of intact melatonin in man is described. The melatonin clearance values were, however, obtained either after the oral intake of melatonin, or by applying different techniques for the determination of melatonin in urine and plasma. In this study, renal clearance of melatonin was determined during the hours where melatonin concentrations are relatively constant. Melatonin levels in plasma and urine respectively were each deter­mined by three analytical techniques, i.e. the Fraser, NID and WHB methods. The results show renal clearance of melatonin to be under 2 ml/min and that higher values are obtained with analytical techniques which bypass the extraction process.Slegs twee publikasies bestaan waarin die omvang van die renale opruiming van melatonien in mense beskryf word. Die melatonienopruimingswaardes is egter verkry na óf orale toediening van melatonien óf deur verskillende tegnieke te gebruik vir die bepaling van melatonien in die plasma en urien onderskeidelik. In hierdie studie is melatonienopruiming bepaal oor 'n tyd van die dag wanneer die plasmavlakke relatief konstant bly, en is die melatonienvlakke in plasma en urien elk onderskeidelik met die Fraser-, NID- en WHB-metodes bepaal. Die resultate toon dat melatonienopruiming onder 2 ml/min is en dat hoër waardes verkry word wanneer van metodes gebruik gemaak word wat die ekstraksieprosedures omseil.

Editorial Office

1996-07-01

244

Melatonin Therapy in Patients with Alzheimer’s Disease  

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Full Text Available Alzheimer’s disease (AD is a major health problem and a growing recognition exists that efforts to prevent it must be undertaken by both governmental and non-governmental organizations. In this context, the pineal product, melatonin, has a promising significance because of its chronobiotic/cytoprotective properties potentially useful for a number of aspects of AD. One of the features of advancing age is the gradual decrease in circulating melatonin levels. A limited number of therapeutic trials have indicated that melatonin has a therapeutic value as a neuroprotective drug in the treatment of AD and minimal cognitive impairment (which may evolve to AD. Both in vitro and in vivo, melatonin prevented the neurodegeneration seen in experimental models of AD. For these effects to occur, doses of melatonin about two orders of magnitude higher than those required to affect sleep and circadian rhythmicity are needed. More recently, attention has been focused on the development of potent melatonin analogs with prolonged effects, which were employed in clinical trials in sleep-disturbed or depressed patients in doses considerably higher than those employed for melatonin. In view that the relative potencies of the analogs are higher than that of the natural compound, clinical trials employing melatonin in the range of 50–100 mg/day are urgently needed to assess its therapeutic validity in neurodegenerative disorders such as AD.

Daniel P. Cardinali

2014-04-01

245

Relation of Melatonin to Sleep Architecture in Children with Autism  

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Children with autism often suffer from sleep disturbances, and compared to age-matched controls, have decreased melatonin levels, as indicated by urine levels of the primary melatonin metabolite, 6-sulfatoxymelatonin (6-SM). We therefore investigated the relationship between 6-SM levels and sleep architecture in children with autism spectrum…

Leu, Roberta M.; Beyderman, Liya; Botzolakis, Emmanuel J.; Surdyka, Kyla; Wang, Lily; Malow, Beth A.

2011-01-01

246

Melatonin Signaling Modulates Clock Genes Expression in the Mouse Retina  

Science.gov (United States)

Previous studies have shown that retinal melatonin plays an important role in the regulation of retinal daily and circadian rhythms. Melatonin exerts its influence by binding to G-protein coupled receptors named melatonin receptor type 1 and type 2 and both receptors are present in the mouse retina. Earlier studies have shown that clock genes are rhythmically expressed in the mouse retina and melatonin signaling may be implicated in the modulation of clock gene expression in this tissue. In this study we determined the daily and circadian expression patterns of Per1, Per2, Bmal1, Dbp, Nampt and c-fos in the retina and in the photoreceptor layer (using laser capture microdissection) in C3H-f+/+ and in melatonin receptors of knockout (MT1 and MT2) of the same genetic background using real-time quantitative RT-PCR. Our data indicated that clock and clock-controlled genes are rhythmically expressed in the retina and in the photoreceptor layer. Removal of melatonin signaling significantly affected the pattern of expression in the retina whereas in the photoreceptor layer only the Bmal1 circadian pattern of expression was affected by melatonin signaling removal. In conclusion, our data further support the notion that melatonin signaling may be important for the regulation of clock gene expression in the inner or ganglion cells layer, but not in photoreceptors. PMID:25203735

Coulson, Elise; Kunst, Stefanie; Spessert, Rainer; Tosini, Gianluca

2014-01-01

247

Melatonin and colon carcinogenesis. II. Intestinal melatonin-containing cells and serum melatonin level in rats with 1,2-dimethylhydrazine-induced colon tumors.  

Science.gov (United States)

Two-month-old outbred female LIO rats were injected weekly with a single dose of 1,2-dimethylhydrazine (DMH; 21 mg/kg of body weight) administered s.c. for 15 consecutive weeks. From the day of the 1st injection of the carcinogen the part of rats were given five days a week during the night time (from 18.00 h to 08.00 h) melatonin dissolved in tap water, 20 mg/l. The experiment was terminated in 6 months after the first injection of the carcinogen. The concentration of melatonin in the serum was estimated by radioimmunoassay in rats exposed to DMH alone or in intact control rats in the morning (between 10.00 and 11.00 hours) and night (between 24.00 and 01.00 hours) time. Number of melatonin-containing cells (M-cells) and their optical density were estimated by immunohistology in normal mucosa of glandular stomach, duodenum, ileum and descending colon of tumor-bearing animals from groups exposed to DMH or DMH+melatonin. It was shown that serum melatonin levels in rats with colon tumors was increased as compared with controls. However there was no diurnal rhythm of serum melatonin of colon tumor-bearing animals as compared to intact controls. The number of M-cells was decreased in all tissues studied in rats with DMH-induced colon tumors in comparison to corresponding controls: by 2.0 times in stomach, by 1.8 time in duodenum, by 1.3 times in ileum, and by 1.8 times in colon. In ileum and colon of rats treated with DMH+melatonin the number of M-cells was similar to control level whereas in stomach and duodenum this number was significantly higher than that in rats treated with DMH alone, but less than in corresponding controls. Relative content of melatonin in enterochromaffin cells of all parts of gastrointestinal tract evaluated as optical density of the cells and was decreased in rats exposed with DMH alone in comparison to the controls and was normalized and similar to the norm level in rats treated with DMH+melatonin. Thus, exogenous melatonin prevent a decrease in numbers of melatonin-containing cells as was observed in gastrointestinal tract (GIT) of rats exposed to DMH. This preventive action of melatonin correlated well with its anticarcinogenic effect. PMID:10048713

Anisimov, V N; Kvetnoy, I M; Chumakova, N K; Kvetnaya, T V; Molotkov, A O; Pogudina, N A; Popovich, I G; Popuchiev, V V; Zabezhinski, M A; Bartsch, H; Bartsch, C

1999-01-01

248

Visual orientation and navigation in nocturnal arthropods.  

Science.gov (United States)

With their highly sensitive visual systems, the arthropods have evolved a remarkable capacity to orient and navigate at night. Whereas some navigate under the open sky, and take full advantage of the celestial cues available there, others navigate in more difficult conditions, such as through the dense understory of a tropical rainforest. Four major classes of orientation are performed by arthropods at night, some of which involve true navigation (i.e. travel to a distant goal that lies beyond the range of direct sensory contact): (1) simple straight-line orientation, typically for escape purposes; (2) nightly short-distance movements relative to a shoreline, typically in the context of feeding; (3) long-distance nocturnal migration at high altitude in the quest to locate favorable feeding or breeding sites, and (4) nocturnal excursions to and from a fixed nest or food site (i.e. homing), a task that in most species involves path integration and/or the learning and recollection of visual landmarks. These four classes of orientation--and their visual basis--are reviewed here, with special emphasis given to the best-understood animal systems that are representative of each. PMID:20733292

Warrant, Eric; Dacke, Marie

2010-01-01

249

Artificial light and nocturnal activity in gammarids  

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Full Text Available Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month’s exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift.

Elizabeth K. Perkin

2014-03-01

250

Daily melatonin supplementation in mice increases atherosclerosis in proximal aorta.  

Science.gov (United States)

Considerable evidence supports the hypothesis that LDL oxidation plays an important role in atherosclerosis. Even though high melatonin doses inhibit LDL oxidation in vitro, the effect of melatonin on atherosclerosis has never been studied. We have demonstrated that the feeding of hypercholesterolemic mice with an atherogenic diet supplemented with melatonin highly increases the surface of atherosclerotic lesions in the proximal aorta. These observations occur without detectable lipidic or glucidic phenotype alteration. Melatonin treatment increased highly the sensitivity of atherogenic lipoprotein to Cu(2+) and gamma-radiolysis generated oxyradical ex vivo oxidation during the fasting period. Moreover, these altered lipoproteins were less recognized by the LDL receptor metabolic pathway of murine fibroblasts while they transferred many more cholesteryl esters to murine macrophages. This study suggests that caution should be taken as regards high melatonin dosage in hypercholesterolemic patients. PMID:12051775

Tailleux, Anne; Torpier, Gérard; Bonnefont-Rousselot, Dominique; Lestavel, Sophie; Lemdani, Mohamed; Caudeville, Bernadette; Furman, Christophe; Foricher, Rachel; Gardes-Albert, Monique; Lesieur, Daniel; Rolando, Christian; Teissier, Elisabeth; Fruchart, Jean-Charles; Clavey, Véronique; Fievet, Catherine; Duriez, Patrick

2002-05-10

251

Melatonin prevents neonatal dexamethasone induced programmed hypertension: Histone deacetylase inhibition.  

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Adulthood hypertension can be programmed by corticosteroid exposure in early life. Oxidative stress, epigenetic regulation by histone deacetylases (HDACs), and alterations of renin-angiotensin system (RAS) are involved in the developmental programming of hypertension. We examined whether melatonin prevented neonatal dexamethasone (DEX)-induced programmed hypertension and how melatonin prevented these processes. We also examined whether HDAC inhibition by trichostatin A (TSA, a HDAC inhibitor) had similar effects. Male offspring were assigned to 5 groups (n=6/group): control, DEX, melatonin, DEX+melatonin, and DEX+TSA. Male rat pups were injected i.p. with DEX on day 1 (0.5mg/kg BW), day 2 (0.3mg/kg BW), and day 3 (0.1mg/kg BW) after birth. Melatonin was administered in drinking water at the dose of 0.01% during the lactation period. The DEX+TSA group received DEX and 0.5mg/kg TSA subcutaneous injection once daily for 1 week. All rats were killed at 16 weeks of age. Neonatal DEX exposure induced hypertension in male offspring at 16 weeks of age, which melatonin prevented. Neonatal DEX exposure decreased gene expression related to apoptosis, nephrogenesis, RAS, and sodium transporters. Yet DEX treatment increased protein levels of HDAC-1, -2, and -3 in the kidney. Melatonin therapy preserved the decreases of gene expression and decreased HDACs. Similarly, HDAC inhibition prevented DEX-induced programmed hypertension. In conclusion, melatonin therapy exerts a long-term protection against neonatal DEX-induced programmed hypertension. Its beneficial effects include alterations of RAS components and inhibition of class I HDACs. Given that the similar protective effects of melatonin and TSA, melatonin might inhibit HDACs to epigenetic regulation of hypertension-related genes to prevent programmed hypertension. PMID:25090636

Wu, Ting-Hsin; Kuo, Hsuan-Chang; Lin, I-Chun; Chien, Shao-Ju; Huang, Li-Tung; Tain, You-Lin

2014-10-01

252

Circadian mechanisms in the regulation of melatonin synthesis: disruption with light at night and the pathophysiological consequences  

Directory of Open Access Journals (Sweden)

Full Text Available In the past two decades, the results of a number of epidemiological studies have uncovered an association between excessive light exposure at night and the prevalence of cancer. Whereas the evidence supporting this link is strongest between nighttime light and female breast and male prostate cancer, the frequency of other tumor types may also be elevated. Individuals who have the highest reported increase in cancer are chronic night shift workers and flight attendants who routinely fly across numerous time zones. There are at least two obvious physiological consequences of nighttime light exposure, i.e., a reduction in circulating melatonin levels and disruption of the circadian system (chronodisruption. Both these perturbations in experimental animals aggravate tumor growth. Melatonin has a long investigative history in terms of its ability to stymie the growth of many tumor types. Likewise, in the last decade chronodisruption has been unequivocally linked to a variety of abnormal metabolic conditions including excessive tumor growth. This brief review summarizes the processes by which light after darkness onset impedes melatonin production and disturbs circadian rhythms. The survey also reviews the evidence associating the ostensible danger of excessive nighttime light pollution to cancer risk. If an elevated tumor frequency is definitively proven to be a consequence of light at night and/or chronodisruption, it seems likely that cancer will not be the exclusive pathophysiological change associated with the rampant light pollution characteristic of modern societies. [J Exp Integr Med 2011; 1(1: 13-22

Ahmet Korkmaz

2011-02-01

253

Melatonin, melatonin isomers and stilbenes in Italian traditional grape products and their antiradical capacity.  

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Although polyphenols represent the paradigm of the health-promoting effects ascribed to grape products, recently, attention has been paid to dietary melatonin, significantly present in Mediterranean foods. In this work, we measured melatonin, its isomers, stilbenes (trans- and cis-resveratrol and their glucosides, piceids) and total polyphenols in some different grape products (red, white and dessert wines, grape juices and Modena balsamic vinegars) of distinct Italian areas. We also evaluated their antiradical activity by DPPH(·) and ABTS(·+) assays. For indoleamine analysis, the separation was carried out on a 1.7-?m C18 BEH column and the detection performed by means of mass spectrometry with electrospray ionization in positive ion mode with multiple reaction monitoring. The confirmation of the peak identity was accomplished by injection into the high-resolution system (Orbitrap) using accurate mass measurements (error below 1.0 ppm). Mass spectrometry analyses revealed, for the first time, the presence of melatonin in dessert wines and balsamic vinegars, as well as the occurrence of three different melatonin isomers in grape products. PMID:23171152

Vitalini, Sara; Gardana, Claudio; Simonetti, Paolo; Fico, Gelsomina; Iriti, Marcello

2013-04-01

254

Influence of melatonin on fatigue severity in patients with chronic fatigue syndrome and late melatonin secretion.  

Science.gov (United States)

The effect of melatonin, a chronobiotic drug, was explored in 29 patients with chronic fatigue syndrome (CFS) and Dim Light Melatonin onset (DLMO) later than 21.30 hours, reflective of delayed circadian rhythmicity. The patients took 5 mg of melatonin orally, 5 h before DLMO during 3 months. Their responses to the checklist individual strength (CIS), a reliable questionnaire measuring the severity of personally experienced fatigue, were assessed twice with a 6-week interval immediately before the treatment and once after 3 months treatment. In the pre-treatment period the fatigue sub-score improved significantly. After treatment, the total CIS score and the sub-scores for fatigue, concentration, motivation and activity improved significantly. The sub-score fatigue normalized in two of the 29 patients in the pre-treatment period and in eight of 27 patients during treatment. This change was significant. In the patients with DLMO later than 22.00 hours (n=21) the total CIS score and the sub-scores for fatigue, concentration and activity improved significantly more than in the patients (n=8) with DLMO earlier than 22.00 hours. Melatonin may be an effective treatment for patients with CFS and late DLMO, especially in those with DLMO later than 22.00 hours. PMID:16420393

van Heukelom, R O; Prins, J B; Smits, M G; Bleijenberg, G

2006-01-01

255

Bat predation on nocturnally migrating birds  

Science.gov (United States)

Bat predation on birds is a very rare phenomenon in nature. Most documented reports of bird-eating bats refer to tropical bats that occasionally capture resting birds. Millions of small birds concentrate and cross over the world's temperate regions during migration, mainly at night, but no nocturnal predators are known to benefit from this enormous food resource. An analysis of 14,000 fecal pellets of the greater noctule bat (Nyctalus lasiopterus) reveals that this species captures and eats large numbers of migrating passerines, making it the only bat species so far known that regularly preys on birds. The echolocation characteristics and wing morphology of this species strongly suggest that it captures birds in flight. PMID:11493689

Ibanez, Carlos; Juste, Javier; Garcia-Mudarra, Juan L.; Agirre-Mendi, Pablo T.

2001-01-01

256

Nocturnal bruxism and hypnotherapy: a case study.  

Science.gov (United States)

This article describes a case study of a hypnotherapeutic treatment of nocturnal bruxism. The author saw the client for a total of 7 sessions. Hypnotherapy was interspersed with an exploration of tacit and initially denied hostility in the client's life as well as aspects of a somewhat difficult childhood. At the end, the bruxism had disappeared. Follow-up 1 year later indicated that the bruxism had not returned, and the client had become more assertive in her relations with others and had more exploratory activities in her life directions. The latter had not been dealt with in therapy. Thus, there appeared to be a "ripple effect" of successful therapy from one part of her life into its other aspects. PMID:23427844

Dowd, E Thomas

2013-01-01

257

Nocturnal frontal lobe epilepsy in mucopolysaccharidosis.  

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Nocturnal frontal lobe epilepsy (NFLE) is an epileptic syndrome that is primarily characterized by seizures with motor signs occurring almost exclusively during sleep. We describe 2 children with mucopolysaccharidosis (MPS) who were referred for significant sleep disturbance. Long term video-EEG monitoring (LT-VEEGM) demonstrated sleep-related hypermotor seizures consistent with NFLE. No case of sleep-related hypermotor seizures has ever been reported to date in MPS. However, differential diagnosis with parasomnias has been previously discussed. The high frequency of frontal lobe seizures causes sleep fragmentation, which may result in sleep disturbances observed in at least a small percentage of MPS patients. We suggest monitoring individuals with MPS using periodic LT-VEEGM, particularly when sleep disorder is present. Moreover, our cases confirm that NFLE in lysosomal storage diseases may occur, and this finding extends the etiologic spectrum of NFLE. PMID:24447995

Bonanni, Paolo; Volzone, Anna; Randazzo, Giovanna; Antoniazzi, Lisa; Rampazzo, Angelica; Scarpa, Maurizio; Nobili, Lino

2014-10-01

258

Nocturnal flow on a western Colorado slope  

International Nuclear Information System (INIS)

The Department of Energy sponsored Atomspheric Studies in Complex Terrain (ASCOT) program has conducted a research program designed to increase our knowledge and understanding of terrain-dominated flows with specific emphasis on nocturnal flows within mountain valleys. ASCOT has sponsored both field studies and numerical modeling efforts to improve our understanding of the wind, temperature and turbulence structure of nocturnal drainage flows. One of the most recent ASCOT sponsored field studies involves a study within the Mesa Creek Basin in western Colorado to investigate the seasonal frequency of occurrence of drainage flows along the sloped surfaces and within the basin, and to evaluate the effect of the ambient meteorology on their development. The Mesa Creek Basin, situated on the north slope of the Grand Mesa, encompasses a roughly 10 x 20 km area that is approximately 30 km east of Grand Junction. The observational segment of the study was undertaken jointly by the Lawrence Livermore National Laboratory and the NOAA Wave Propagation Laboratory, and involved the operation of network of eight meteorological towers and a monostatic sodar within the Mesa Creek study area over a period of one year that extended from December 1988 through November 1989. These measurements were augmented by tethersonde observations to define the vertical wind and temperature structure during a few nights. The modeling portion of the study is being undertaken by Lawrence Livermore Laboratory using a three-dimensional prognostic boundary layer model to gain further insight into the dynamics of the seasonal variations and the effect of cloud cover on the development of the drainage flows. It is the purpose of this paper to present preliminary results form a numerical simulation done as part of this study. 4 refs., 7 figs

259

Melatonin prevents human pancreatic carcinoma cell PANC-1-induced human umbilical vein endothelial cell proliferation and migration by inhibiting vascular endothelial growth factor expression.  

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Melatonin is an important natural oncostatic agent, and our previous studies have found its inhibitory action on tumor angiogenesis, but the mechanism remains unclear. It is well known that vascular endothelial growth factor (VEGF) plays key roles in tumor angiogenesis and has become an important target for antitumor therapy. Pancreatic cancer is a representative of the most highly vascularized and angiogenic solid tumors, which responds poorly to chemotherapy and radiation. Thus, seeking new treatment strategies targeting which have anti-angiogenic capability is urgent in clinical practice. In this study, a co-culture system between human umbilical vein endothelial cells (HUVECs) and pancreatic carcinoma cells (PANC-1) was used to investigate the direct effect of melatonin on the tumor angiogenesis and its possible action on VEGF expression. We found HUVECs exhibited an increased cell proliferation and cell migration when co-cultured with PANC-1 cells, but the process was prevented when melatonin added to the incubation medium. Melatonin at concentrations of 1??m and 1?mm inhibited the cell proliferation and migration of HUVECs and also decreased both the VEGF protein secreted to the cultured medium and the protein produced by the PANC-1 cells. In addition, the VEGF mRNA expression was also down-regulated by melatonin. Taken together, our present study shows that melatonin at pharmacological concentrations inhibited the elevated cell proliferation and cell migration of HUVECs stimulated by co-culturing them with PANC-1 cells; this was associated with a suppression of VEGF expression in PANC-1 cells. PMID:21913973

Cui, Peilin; Yu, Minghua; Peng, Xingchun; Dong, Lv; Yang, Zhaoxu

2012-03-01

260

Effect of melatonin on human dental papilla cells.  

Science.gov (United States)

Melatonin regulates a variety of biological processes, which are the control of circadian rhythms, regulation of seasonal reproductive function and body temperature, free radical scavenging and so on. Our previous studies have shown that various cells exist in human and mouse tooth germs that express the melatonin 1a receptor (Mel1aR). However, little is known about the effects of melatonin on tooth development and growth. The present study was performed to examine the possibility that melatonin might exert its influence on tooth development. DP-805 cells, a human dental papilla cell line, were shown to express Mel1aR. Expression levels of mRNA for Mel1aR in DP-805 cells increased until 3 days after reaching confluence and decreased thereafter. Real-time reverse transcription-polymerase chain reaction showed that melatonin increased the expression of mRNAs for osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotin (DSPP). Melatonin also enhanced the mineralized matrix formation in DP-805 cell cultures in a dose-dependent manner. These results strongly suggest that melatonin may play a physiological role in tooth development/growth by regulating the cellular function of odontogenic cells in tooth germs. PMID:25264744

Tachibana, Ryusuke; Tatehara, Seiko; Kumasaka, Shuku; Tokuyama, Reiko; Satomura, Kazuhito

2014-01-01

 
 
 
 
261

Melatonin and Atopy: Role in Atopic Dermatitis and Asthma  

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Melatonin may have important immunostimulatory actions in allergic diseases, in addition to its well-known antioxidant and cytoprotective effects in several inflammatory conditions. The activation of the immune system leads to free radical production associated with decreased melatonin levels and depressed antioxidant enzyme activities in several inflammatory diseases. Many skin disorders, including atopic dermatitis, are accompanied by infiltration and activation of mast cells, which release vasoactive and proinflammatory mediators. Experimental data suggest that melatonin inhibits development of atopic eczema and reduces serum total IgE and IL-4. Allergic asthma is a condition characterized by bronchial hyperresponsiveness and the presence of IgE antibodies in response to inhaled allergens; often there is also enhanced total serum IgE levels. Melatonin regulates smooth muscle tone and influences the immune response. Melatonin may, however, act as a pro-inflammatory agent in asthma leading to bronchial constriction. The safety of melatonin as a sleep-inducing agent has been confirmed in asthmatic subjects, but its routine use is not recommended in bronchial asthma. This review summarizes what is known about the role of melatonin as an immunomodulatory agent in asthma and atopic eczema. PMID:25093714

Marseglia, Lucia; D'Angelo, Gabriella; Manti, Sara; Salpietro, Carmelo; Arrigo, Teresa; Barberi, Ignazio; Reiter, Russel J.; Gitto, Eloisa

2014-01-01

262

Benzocyclobutane, benzocycloheptane and heptene derivatives as melatonin agonists and antagonists.  

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Two series of analogues were designed, synthesised and evaluated as potential human melatonin type?1 and?2 receptor (hMT1 and hMT2 ) ligands. Their biological effects were assessed by a well-established, specific model of melatonin action, the pigment response of Xenopus laevis melanophores. Compounds containing a benzocyclobutane scaffold and a methoxy group in the "melatonin" orientation were found to be potent agonists, with one of the analogues exhibiting activity comparable to melatonin. In contrast, analogues with a methoxy group in non-melatonin positions or with multiple methoxy groups showed either weaker agonist activity or were antagonists. Benzocycloheptene derivatives with one methoxy group are found to be weak agonists, whereas those with two methoxy groups were found to be antagonists, as were all of the benzocycloheptane derivatives evaluated. The most active compounds were assessed in a human receptor radio ligand binding assay but showed little discrimination between MT1 and MT2 . These results again show that the indole nitrogen of melatonin is not a necessary component for analogue activity and also illustrate that replacement of the indole ring with a 4-membered carbocycle can provide highly active compounds when the methoxy group is in the melatonin position. PMID:25044938

Tsotinis, Andrew; Afroudakis, Pandelis A; Garratt, Peter J; Bocianowska-Zbrog, Alina; Sugden, David

2014-10-01

263

Solubilization and purification of melatonin receptors from lizard brain  

International Nuclear Information System (INIS)

Melatonin receptors in lizard brain were identified and characterized using 125I-labeled melatonin ([125I]MEL) after solubilization with the detergent digitonin. Saturation studies of solubilized material revealed a high affinity binding site, with an apparent equilibrium dissociation constant of 181 +/- 45 pM. Binding was reversible and inhibited by melatonin and closely related analogs, but not by serotonin or norepinephrine. Treatment of solubilized material with the non-hydrolyzable GTP analog, guanosine 5'-(3-O-thiotriphosphate) (GTP-gamma-S), significantly reduced receptor affinity. Gel filtration chromatography of solubilized melatonin receptors revealed a high affinity, large (Mr 400,000) peak of specific binding. Pretreatment with GTP-gamma-S before solubilization resulted in elution of a lower affinity, smaller (Mr 150,000) peak of specific binding. To purify solubilized receptors, a novel affinity chromatography resin was developed by coupling 6-hydroxymelatonin with Epoxy-activated Sepharose 6B. Using this resin, melatonin receptors were purified approximately 10,000-fold. Purified material retained the pharmacologic specificity of melatonin receptors. These results show that melatonin receptors that bind ligand after detergent treatment can be solubilized and substantially purified by affinity chromatography

264

Effect of Melatonin on Human Dental Papilla Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Melatonin regulates a variety of biological processes, which are the control of circadian rhythms, regulation of seasonal reproductive function and body temperature, free radical scavenging and so on. Our previous studies have shown that various cells exist in human and mouse tooth germs that express the melatonin 1a receptor (Mel1aR. However, little is known about the effects of melatonin on tooth development and growth. The present study was performed to examine the possibility that melatonin might exert its influence on tooth development. DP-805 cells, a human dental papilla cell line, were shown to express Mel1aR. Expression levels of mRNA for Mel1aR in DP-805 cells increased until 3 days after reaching confluence and decreased thereafter. Real-time reverse transcription-polymerase chain reaction showed that melatonin increased the expression of mRNAs for osteopontin (OPN, osteocalcin (OCN, bone sialoprotein (BSP, dentin matrix protein-1 (DMP-1 and dentin sialophosphoprotin (DSPP. Melatonin also enhanced the mineralized matrix formation in DP-805 cell cultures in a dose-dependent manner. These results strongly suggest that melatonin may play a physiological role in tooth development/growth by regulating the cellular function of odontogenic cells in tooth germs.

Ryusuke Tachibana

2014-09-01

265

Growth conditions determine different melatonin levels in Lupinus albus L.  

Science.gov (United States)

Melatonin, an indoleamine, which has recently been assigned several roles in plant physiology as a growth promoter, as rooting agent, and as antioxidant in senescence delay and cytoprotection, seems to have a relevant function in plant stress situations. The presence of melatonin increases the resistance of lupin plant tissues (Lupinus albus L.) against natural or artificially induced adverse situations. In this work, we studied the response of lupin plants in controlled stress situations (drought-, anaerobic-, pH-, and cold stress and using ZnSO4 , NaCl, and H2 O2 as chemical stressors) and measured the changes in endogenous melatonin levels in lupin plants. Also, the effect of abscisic acid, ethylene, and natural environmental conditions were evaluated. In general, nearly all stressful factors caused an increase in melatonin in the investigated organs. The chemical stress provoked by ZnSO4 or NaCl caused the most pronounced changes in the endogenous level of melatonin, followed by cold and drought stressors. In some cases, the level of melatonin increased 12-fold with respect to the levels in control plants, indicating that melatonin biosynthesis is upregulated in common stress situations, in which it may serve as a signal molecule and/or as a direct antistress agent due to its well-known antioxidative properties. PMID:23600673

Arnao, Marino B; Hernández-Ruiz, Josefa

2013-09-01

266

Melatonin and Atopy: Role in Atopic Dermatitis and Asthma  

Directory of Open Access Journals (Sweden)

Full Text Available Melatonin may have important immunostimulatory actions in allergic diseases, in addition to its well-known antioxidant and cytoprotective effects in several inflammatory conditions. The activation of the immune system leads to free radical production associated with decreased melatonin levels and depressed antioxidant enzyme activities in several inflammatory diseases. Many skin disorders, including atopic dermatitis, are accompanied by infiltration and activation of mast cells, which release vasoactive and proinflammatory mediators. Experimental data suggest that melatonin inhibits development of atopic eczema and reduces serum total IgE and IL-4. Allergic asthma is a condition characterized by bronchial hyperresponsiveness and the presence of IgE antibodies in response to inhaled allergens; often there is also enhanced total serum IgE levels. Melatonin regulates smooth muscle tone and influences the immune response. Melatonin may, however, act as a pro-inflammatory agent in asthma leading to bronchial constriction. The safety of melatonin as a sleep-inducing agent has been confirmed in asthmatic subjects, but its routine use is not recommended in bronchial asthma. This review summarizes what is known about the role of melatonin as an immunomodulatory agent in asthma and atopic eczema.

Lucia Marseglia

2014-08-01

267

Prolonged-release melatonin for insomnia – an open-label long-term study of efficacy, safety, and withdrawal  

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Full Text Available Patrick Lemoine1, Doron Garfinkel2, Moshe Laudon3, Tali Nir3, Nava Zisapel3,41The Clinique Lyon-Lumière, Meyzieu, France; 2Geriatric-Palliative Department, Shoham Geriatric Medical Center, Pardes Hanna, Israel; 3Neurim Pharmaceuticals Ltd, Tel-Aviv, Israel; 4Department of Neurobiology Faculty of Life Sciences, Tel Aviv University, Tel Aviv, IsraelBackground: Prolonged-release melatonin (PRM 2 mg is indicated for insomnia in patients aged 55 years and older. A recent double-blind placebo-controlled study demonstrated 6-month efficacy and safety of PRM in insomnia patients aged 18–80 and lack of withdrawal and rebound symptoms upon discontinuation.Objective: To investigate the efficacy, safety, and withdrawal phenomena associated with 6–12 months PRM treatment.Methods: Data from a prospective 6–12-month open-label study of 244 community dwelling adults with primary insomnia, who had participated in a placebo-controlled, double-blind dose-ranging trial of PRM. Patients received PRM nightly, followed by a 2-week withdrawal period. Main outcome measures were patient-reported sleep quality ratings (diary, adverse events, vital signs, and laboratory tests recorded at each visit, and withdrawal symptoms (CHESS-84 [Check-list Evaluation of Somatic Symptoms]. Nocturnal urinary 6-sulfatoxymelatonin excretion, a measure of the endogenous melatonin production, was assessed upon discontinuing long-term PRM.Results: Of the 244 patients, 36 dropped out, 112 completed 6 months of treatment, and the other 96 completed 12 months of treatment. The mean number of nights by which patients reported sleep quality as "good" or "very good" was significantly higher during PRM than before treatment. There was no evidence of tolerance to PRM. Discontinuation of PRM was not associated with rebound insomnia or withdrawal symptoms; on the contrary, residual benefit was observed. PRM was well tolerated, and there was no suppression of endogenous melatonin production.Conclusion: Results support the efficacy and safety of PRM in primary insomnia patients aged 20–80 throughout 6–12 months of continuous therapy. PRM discontinuation even after 12 months was not associated with adverse events, withdrawal symptoms, or suppression of endogenous melatonin production.Keywords: PRM, adverse events, sleep, insomnia, patients

Lemoine P

2011-07-01

268

Spectral modulation of light wavelengths using optical filters: effect on melatonin secretion.  

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Shiftwork has been identified as a risk factor for various medical problems, such as cancer, heart disease, metabolic disturbances, depression, and anxiety disorders, and as reviewed this month, adverse reproductive function. Shiftwork misaligns physiological rhythms with respect to each other and to external environmental rhythms such as the 24-hour light/dark cycle. Light is the strongest time cue for entraining circadian rhythms in mammals, and aberrant light exposure patterns during shiftwork is one of the key factors that induce circadian misalignment. We have recently demonstrated, in both animal and clinical models, that filtering short wavelengths (below 480 nm) from nocturnal lighting can attenuate alterations in hormone secretion (melatonin and glucocorticoids) and in central and peripheral clock gene expression induced by nighttime light exposure. We also demonstrated that the use of optical filters led to an improvement in mood and in cognitive performance under controlled laboratory conditions and during field-based shiftwork studies. Moreover, there was an increase in sleep duration and quality on nights immediately following night shifts. We believe it is likely that optical filters incorporated into glasses or as coverings for light bulbs could be used as a method to improve or prevent many of the medical problems associated with circadian misalignment and rotating shiftwork. PMID:25015557

Casper, Robert F; Rahman, Shadab

2014-08-01

269

Acute allograft rejection and immunosuppression: influence on endogenous melatonin secretion.  

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Melatonin displays a dose-dependent immunoregulatory effect in vitro and in vivo. Exogenous high-dose melatonin therapy exerted an immunosuppressive effect, abrogating acute rejection (AR), significantly prolonging transplant survival. Endogenous melatonin secretion, in response to heterotopic rat cardiac allograft transplantation (Tx), was investigated during the AR response and under standardized immunosuppressive maintenance therapy with cyclosporin A (CsA) and rapamycin (RPM). Recipients of syngeneic transplants, and recipients of allogeneic grafts, either untreated or receiving immunosuppressive therapy constituted the experimental groups. Endogenous circadian melatonin levels were measured at 07:00, 19:00, and 24:00 hr, using a novel radioimmunoassay (RIA) procedure, under standardized 12-hr-light/dark-conditions (light off: 19:00 hr; light on: 07:00 hr), before and after Tx. Neither the operative trauma, nor the challenge with a perfused allograft or the AR response influenced endogenous melatonin peak secretion. Immunosuppressive therapy with CsA led to a significant increase in peak secretion, measured for days 7 (212 +/- 40.7 pg/mL; P < 0.05), 14 (255 +/- 13.9 pg/mL; P < 0.001), and 21 (219 +/- 34 pg/mL; P < 0.01) after Tx, as compared with naïve animals (155 +/- 25.8 pg/mL). In contrast, treatment with RPM significantly decreased the melatonin peak post-Tx up to day 7 (87 +/- 25.2 pg/mL; P < 0.001), compared with naïve animals (155 +/- 25.8 pg/mL). These findings imply a robust nature of the endogenous circadian melatonin secretion kinetics, even against the background of profound allogeneic stimuli. Immunosuppressive maintenance therapy with CsA and RPM modulated early melatonin secretion, indicating a specific secondary action of these drugs. Further studies are necessary to disclose the long-term effect of immunosuppressive therapy on circadian melatonin secretion in transplant recipients. PMID:18339121

Cardell, Markus; Jung, Florian Johannes; Zhai, Wei; Hillinger, Sven; Welp, Andre; Manz, Bernhard; Weder, Walter; Korom, Stephan

2008-04-01

270

Diurnal rhythm of melatonin binding in the rat suprachiasmatic nucleus  

International Nuclear Information System (INIS)

We used quantitative in vitro autoradiography to localize and characterize 2-125I-melatonin binding sites in the rat suprachiasmatic nuclei in relation to pineal melatonin production. In a light:dark cycle of 12:12 h, binding density exhibited significant diurnal variation with a peak at the dark-light transition and a trough 12 hours later. Saturation studies suggested that the decreased binding at light-dark transition might be due to a shift of the putative melatonin receptor to a low affinity state

271

Reactions of melatonin with radicals in deoxygenated aqueous solution  

International Nuclear Information System (INIS)

Reactions of melatonin (N-acetyl-5-methoxytryptamine) with radiolytically generated radicals were studied. Reaction of melatonin with OH radicals is diffusion-controlled (k=1.2 x 1010 dm3 mol-1 x s-1), the main (but not the only one) intermediate being the indolyl-type radical, while the rate constant for the reaction with hydrated electrons is k=4.3 x 108 dm3 x mol-1 x s-1. Melatonin is capable of scavenging tert-butanol radicals, while its reactivity towards polymer radicals of poly(acrylic acid) and poly(vinyl pyrrolidone) is very low. (author)

272

Spina Bifida Occulta in Persistent Primary Nocturnal Enuresis  

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Background/Objectives: Of congenital malformations of the central nervous system 46% are abnormalities of the spinal cord, which includes spina bifida occulta (SBO). The occurrence and significance of spina bifida occulta in patients with persistent primary nocturnal enuresis (PPNE) were evaluated. Materials and Methods: Between January 2000 and February 2001, 109 consecutive children who had nocturnal enuresis more than once a week after the age of 7 years for an uninterrupted period of at l...

Kajbafzadeh, A.; Espandar, L.; Mehdizadeh, M.; Tajik, P.; Mohseni, P.

2004-01-01

273

[Renal vein infarction, a complication of paroxysmal nocturnal hemoglobinuria].  

Science.gov (United States)

Paroxysmal nocturnal hemoglobinuria (Marchiafava-Micheli disease) is a rare acquired clonal disorder of the hematopoietic cell, to a somatic mutation in the phosphatidylinositol glycan (PIG-A). The most frequent clinical manifestations are hemolytic crisis and venous thrombosis of the mesenteric, hepatic, portal or cerebral territories. We report a case of paroxysmal nocturnal hemoglobinuria with renal vein thrombosis, a rare complication of this disease. PMID:22609136

de Charry, Charlotte; de Charry, Félicité; Lemoigne, François; Lamboley, Jean-Laurent; Pasquet, Florian; Pavic, Michel

2012-12-01

274

Development of a melatonin RIA and observation on the plasma melatonin contents in rat models of chronic hyperirritable-depression  

International Nuclear Information System (INIS)

ose in control rats both during summer and winter, while the contents of melatonin during winter were always significantly higher than those during summer in both groups of animals. Conclusion: The newly developed assay was of good specificity and sensitivity with stable agents (65 days). The experimental results demonstrated definite correlationship between the depression disorder and melatonin contents in the rat models, however, the disorder was not seasonally affective. The seasonal variation of the melatonin contents in the animals was due to different duration and intensity of light exposure. (authors)

275

Urinary Melatonin Levels and Skin Malignancy  

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Full Text Available Melatonin inhibits tumor genesis in a variety of in vivo and in vitro experimental models of neoplasia. In industrialized societies, light at night, by suppressing melatonin production, poses a new risk for the development of a variety of cancers such as breast cancer. This effect on skin has been previously studied only in animals and not in humans. Our goal was to examine the relationship between 24-hour 6-sulphatoxymelatonin levels and skin cancer in a case-control study of 70 patients with skin cancer and 70 healthy individuals. The level of 6-sulfatoxymelatonin was measured in 24-hour urine by the ELISA method. In the case group, 55 (78% patients had basal cell carcinoma and 15 (22% had squamous cell carcinoma. The mean level of 24-hour urine 6-sulfatoxymelatonin was significantly higher in the control group (P<0.001. Also, sleep duration had a significant difference between the two groups (P=0.001. It seems that a low level of 24-hour urinary 6-sulfatoxymelatonin renders human beings prone to skin cancer. This association, however, requires further investigation.

Reza Ghaderi

2014-01-01

276

Melatonin: a protective and detoxifying agent in paraquat toxicity  

International Nuclear Information System (INIS)

The ability of melatonin as a protective and detoxifying agent against paraquat-induced oxidative damage in rat lungs and liver was examined. Changes in reduced glutathione (OSH) concentration and malonaldehyde (MDA) level were measured. Pathological examination to lungs and liver was done. Paraquat in 2 doses (20,70 mg/kg) was injected I.P. into rats with melatonin (10 mg/kg) I. P. either before and after paraquat intoxication or only after it. Melatonin proved its protective role when given before and after paraquat intoxication more than its detoxifying effect when given only after paraquat. The biochemical improvement following melatonin therapy was more evident than the histopathological one. (author)

277

Melatonin and clock genes expression in the cardiovascular system.  

Science.gov (United States)

Generation of circadian oscillations is based on rhythmic expression of clock genes and subsequent post-transcriptional and post-translational modifications. In addition to the central circadian oscillator - the suprachiasmatic nucleus (SCN), peripheral oscillators have been demonstrated in many tissues, including the heart and blood vessels. Melatonin mediates cyclic lighting conditions to rhythmic endocrine signal and is able to synchronize neuronal firing in the SCN via membrane receptors. Clock gene expression is melatonin sensitive in the pars tuberalis, genes cry1 and tim1 respond to single injection while neurod1 and npas4 are influenced via long lasting mechanisms. In the rat heart, melatonin phase advanced expression of per2 and bmal1 independently from its effects on the SCN. Melatonin is an important endogenous signal able to synchronize circadian oscillations in the cardiovascular system. It may be effective especially in situations when the circadian control is weakened or organism must adapt to rapid changes in rhythmic environmental conditions. PMID:23277083

Zeman, Michal; Herichova, Iveta

2013-01-01

278

Possible effects of melatonin on the kidney of hyperthyrold rats  

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Full Text Available The aim of this study was to investigate structural changes that occur in the kidney of rats with hyperthyroidism and the effect of melatonin on these changes. The rats were divided into 3 groups; group I was designated as the control, group II was injected daily with 3,3,5-triiodo-L-thyronine (Tg and group III was injected daily with T3+melatonin. After 40 days, tissue specimens of kidney were removed and examined by light and electron microscopy. In the proximal tubule of the Ta injected group, basement membrane thickening, microvillus irregularity and evidence of basal folding were observed. In the glomerule, basal lamina thickening, irregularity of pedicels and somewhere an increase of mesangium were recorded. Moreover, in the melatonin injected group, the findings were similar to the Ts injected group. In conclusion, it was observed that hyperthyroidism caused structural changes in the kidney and melatonin had no important effects on these changes.

Oner J.

2002-01-01

279

New actions of melatonin and their relevance to biometeorology  

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Melatonin is not only produced by the pineal gland, retina and parietal but also by various other tissues and cells from vertebrates, invertebrates, fungi, plants, multicellular algae and by unicells. In plants, many invertebrates and unicells, its concentration often exceeds that found in vertebrate blood by several orders of magnitude. The action of melatonin is highly pleiotropic. It involves firstly, direct effects, via specific binding sites in various peripheral tissues and cells of vertebrates, including immunomodulation; secondly, systemic influences on the cytoskeleton and nitric oxide formation, mediated by calmodulin; and thirdly, antioxidative protection, perhaps also in the context of photoprotection in plants and unicells. In some dinoflagellates, melatonin conveys temperature signals. On the basis of these comparisons, melatonin appears to mediate and modulate influences from several major environmental factors, such as the photoperiod, radiation intensity and temperature.

Hardeland, Rüdiger

280

Radioprotective effects of melatonin on radiation-induced cataract  

International Nuclear Information System (INIS)

One of the mechanisms proposed to explain lens opacification is the oxidation of crystallins, either by radiation or reactive oxygen species (ROS). It has been shown that melatonin has both an anti-peroxidative effect on several tissues and a scavenger effect on ROS. The purpose of this study was to determine the antioxidant role of melatonin (5 mg/kg/day) against radiation-induced cataract in the lens after total-cranium irradiation of rats with a single dose of 5 Gy. Sprague-Dawley rats were divided into four groups. Control group received neither melatonin nor irradiation. Irradiated rats (IR) and melatonin+irradiated rats (IR+Mel) groups were exposed to total cranium irradiation of 5 Gy in a single dose by using a cobalt-60 teletherapy unit. IR+Mel and melatonin (Mel) groups were administered 5 mg/kg melatonin daily by intraperitoneal injections during ten days. Chylack's cataract classification was used in this study. At the end of the 10th day, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes i.e. the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and lipid peroxidation level (malondialdehyde (MDA)). Irradiation significantly increased the MDA level, as an end product of lipid peroxidation, and also significantly decreased SOD and GSH-Px activity, emphasizing the generation of increased oxidative stress. Rats injected with melatonin only did not cause cataract formation. Melatonin suppt cause cataract formation. Melatonin supplementation with irradiation significantly increased the activity of SOD and GSH-Px enzymes and significantly decreased the MDA level. Total cranium irradiation of 5 Gy in a single dose enhanced cataract formation, and melatonin supplementation protected the lenses from radiation-induced cataract formation. Our results suggest that supplementing cancer patients with adjuvant therapy of melatonin may reduce patients suffering from toxic therapeutic regimens such as chemotherapy and/or radiotherapy and may provide an alleviation of the symptoms due to radiation-induced organ injuries. (author)

 
 
 
 
281

Differential effect of melatonin on ?-irradiated ovarian follicles in mice  

International Nuclear Information System (INIS)

The present study was performed to obtain evidence of the radioprotective function of melatonin on the ovarian follicles in ?-irradiated immature mice. Three weeks old immature mice were i.p. injected with 10 ?g and 100 ?g of melatonin dissolved in 100 ?l of alcoholic saline. Two hours after the treatments, they were whole-body irradiated with a dose of LD80(30) (8.3 Gy). The ovaries were dissected out of the animals at -2, 2, 8, and 14 h after the onset of irradiation and prepared for the histological observation using glutaraldehyde fixation. In terms of morphometry, it was observed that the number of primordial follicles of the irradiation group or the melatonin-treated group was less than that of the control. However, the number of primary, preantral, and early antral follicles was not different from that of the control group. In the group pretreated with 100 ?g of melatonin before irradiation, the percentage of normal primordial follicles was significantly higher than that of the irradiation group at any time after irradiation. The high concentration of melatonin also reduced radiation-induced degeneration of the primary follicles at 14 h after irradiation. The pretreatment of 10 ?g of melatonin had little of no effect on radiation-induced degeneration of the primordial follicles and of the primary follicles. However it gave a protective effect on the radiation-induced degeneration in the preantral and early antral follicles. From the above results, it is concluded that the exogenous melatonin has different functions depending on the follicular stages, and that the radioprotective effect of exogenous melatonin on follicular degeneration is related to its concentration. (author)

282

THE EFFECT OF MELATONIN ON CARDIOVASCULAR INDICES DURING EXERCISE  

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The purpose of this study was to determine the effect of melatonin ingestion oncardiopulmonary indexes during rest; exercise and recovery period in female athletes. Heart rate(HR); blood pressure (BP) and maximal oxygen consumption (VO2 max) measured before andafter ingestion of melatonin during exercise. Ten female basketball players whom were playingin Shiraz basketball league; selected for this study based on regularity of their menstrual cyclein last 3 month.They performed the protocol at...

Abbas Ali Gaeini; Mostafa Rahimi; Maryam Soyouf Jahromi; Sirous Choobineh

2011-01-01

283

Original paper Nocturnal Electrobioimpedance Volumetric Assessment (NEVA®: an alternative for determining the quality of nocturnal erections  

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Full Text Available Objectives: The NEVA® device (Urometrics, Inc measures changes in penile blood flow during nocturnal erections and enables one to make the diagnosis of either arterial insufficiency or venous leakage. The RigiScan® (Osbon Medical Systems determines the quality of nocturnal erections to establish the organic or psychogenic nature of erectile dysfunction (ED without indicating the nature of the impotence. This study compares both devices and tries to answer two questions. Does NEVA® give information on nocturnal erections comparable to that provided by the RigiScan®? What is the diagnostic capacity of NEVA® when compared to a comprehensive approach including laboratory examinations, psychological evaluation, intra-cavernous injection, and Duplex Doppler?Material and methods: Twenty-five men with complaints of ED were enrolled in our study. Each of them had a complete work-up. This included the use of the RigiScan® for two consecutive nights. Then the NEVA® and RigiScan® devices were used simultaneously for the third night. The dynamic data provided by the NEVA® system were compared to the conventional nocturnal penile tumescence testing by means of the RigiScan®.Results: An analysis of all sessions shows that all night recordings are comparable. The mean number of erections/night (2.80±0.34 vs 2.76±0.31 does not differ statistically significantly between NEVA® and RigiScan® assessments. Also the mean duration of events (30.66±1.92 minutes vs 25.63±1.62 minutes does not differ. Normal axial rigidity by NEVA® (>200% change over baseline correlates with all grade III erections by RigiScan®. The analysis of NEVA® data gives in 84% of the cases the same diagnosis of ED as that made after a complete work-up.Conclusions: The present study demonstrates that electrobioimpedance registration has a good correlation with conventional penile tumescence testing. The analysis of data obtained with the NEVA® device seems to be an important and easy method for predicting the etiology of ED. For the assessment of the performance of the male partner during a sexual intercourse the registration of axial rigidity is a more important parameter than radial rigidity.

Dirk P.J. Michielsen

2005-09-01

284

Effect of Melatonin on Bone Mineral Density of Irradiated Rats  

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Full Text Available Objective: Melatonin is a powerful endogenous antioxidant and it may play a role in preventionof radiation-induced damage. The aim of this study was to investigate the effect ofmelatonin on bone mineral density in rats receiving radiation.Materials and Methods: Sprague Dawley rats were divided into four groups. Group 1(control group received neither melatonin nor radiation (control group. Group 2 (Melgroup was administered intraperitoneal injections of 5mg/kg melatonin daily for ten days.Group 3 (RT group and Group 4 were exposed to total cranium radiation of 5 Gy in a singledose by using a cobalt-60 teletherapy unit. In addition to irradiation, group 4 (RT + Melgroup was administered 5mg/kg of melatonin intraperitoneally. At the end of the 10th day,the rats' cranium and vertebrae bone mineral densities (BMDs were measured.Results: When cranial BMDs were evaluated, statistically more significant BMD increaseswere seen in the Mel group and the RT + Mel groups than in the control group. No significantdifference was seen in the Mel group versus the RT + Mel group; however, there wasa significant difference between RT and RT + Mel groups. When vertebral BMDs wereevaluated, the only significant difference was found between the control and Mel groups.Conclusion: We think that melatonin is a radioprotective agent. However, we would liketo emphasize that further studies are needed before clinical trials with melatonin are initiated.

Zerrin Orbak

2011-01-01

285

Cardioprotective effect of melatonin against ischaemia/reperfusion damage.  

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Melatonin (N-acetyl-5-methoxytryptamine) has been shown by several workers to protect the heart against ischaemia/reperfusion damage. Melatonin, both in the picomolar and micromolar range, significantly reduces infarct size and improves functional recovery during reperfusion. This may be due to its free radical scavenging and anti-oxidant effects, while the melatonin receptor and its marked anti-adrenergic actions may also be involved. The latter is mediated by nitric oxide (NO), guanylyl cyclase and protein kinase C (PKC). Melatonin-induced cardioprotection is associated with activation of protein kinase B (PKB), extracellular signal-regulated kinase (ERK1/2) (the Reperfusion Injury Salvage Kinase (RISK) pathway) and signal activator and transducer 3 (STAT-3) (the Survivor Activating Factor Enhancement (SAFE) pathway) during reperfusion and inhibition of the mitochondrial permeability transition pore (MPTP). Very little is known about the effect of melatonin on myocardial substrate metabolism. Melatonin was demonstrated to be involved in the regulation of whole body glucose homeostasis via its effects on pancreatic insulin secretion and may thus indirectly affect myocardial substrate metabolism in a circadian manner. PMID:23276991

Lochner, Amanda; Huisamen, Barbara; Nduhirabandi, Frederic

2013-01-01

286

Peripheral and Central Effects of Melatonin on Blood Pressure Regulation  

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Full Text Available The pineal hormone, melatonin (N-acetyl-5-methoxytryptamine, shows potent receptor-dependent and -independent actions, which participate in blood pressure regulation. The antihypertensive effect of melatonin was demonstrated in experimental and clinical hypertension. Receptor-dependent effects are mediated predominantly through MT1 and MT2 G-protein coupled receptors. The pleiotropic receptor-independent effects of melatonin with a possible impact on blood pressure involve the reactive oxygen species (ROS scavenging nature, activation and over-expression of several antioxidant enzymes or their protection from oxidative damage and the ability to increase the efficiency of the mitochondrial electron transport chain. Besides the interaction with the vascular system, this indolamine may exert part of its antihypertensive action through its interaction with the central nervous system (CNS. The imbalance between the sympathetic and parasympathetic vegetative system is an important pathophysiological disorder and therapeutic target in hypertension. Melatonin is protective in CNS on several different levels: It reduces free radical burden, improves endothelial dysfunction, reduces inflammation and shifts the balance between the sympathetic and parasympathetic system in favor of the parasympathetic system. The increased level of serum melatonin observed in some types of hypertension may be a counter-regulatory adaptive mechanism against the sympathetic overstimulation. Since melatonin acts favorably on different levels of hypertension, including organ protection and with minimal side effects, it could become regularly involved in the struggle against this widespread cardiovascular pathology.

Olga Pechanova

2014-10-01

287

Peripheral and central effects of melatonin on blood pressure regulation.  

Science.gov (United States)

The pineal hormone, melatonin (N-acetyl-5-methoxytryptamine), shows potent receptor-dependent and -independent actions, which participate in blood pressure regulation. The antihypertensive effect of melatonin was demonstrated in experimental and clinical hypertension. Receptor-dependent effects are mediated predominantly through MT1 and MT2 G-protein coupled receptors. The pleiotropic receptor-independent effects of melatonin with a possible impact on blood pressure involve the reactive oxygen species (ROS) scavenging nature, activation and over-expression of several antioxidant enzymes or their protection from oxidative damage and the ability to increase the efficiency of the mitochondrial electron transport chain. Besides the interaction with the vascular system, this indolamine may exert part of its antihypertensive action through its interaction with the central nervous system (CNS). The imbalance between the sympathetic and parasympathetic vegetative system is an important pathophysiological disorder and therapeutic target in hypertension. Melatonin is protective in CNS on several different levels: It reduces free radical burden, improves endothelial dysfunction, reduces inflammation and shifts the balance between the sympathetic and parasympathetic system in favor of the parasympathetic system. The increased level of serum melatonin observed in some types of hypertension may be a counter-regulatory adaptive mechanism against the sympathetic overstimulation. Since melatonin acts favorably on different levels of hypertension, including organ protection and with minimal side effects, it could become regularly involved in the struggle against this widespread cardiovascular pathology. PMID:25299692

Pechanova, Olga; Paulis, Ludovit; Simko, Fedor

2014-01-01

288

Melatonin protects rat liver against irradiation-induced oxidative injury  

International Nuclear Information System (INIS)

The aim of this study was to investigate the antioxidant roles of different doses of melatonin (5 and 10 mg kg-1) against ?-irradiation-caused oxidative damage in liver tissue after total body irradiation (TBI) with a single dose of 6.0 Gy. Fifty adult rats were divided into 5 equal groups, 10 rats each. Groups I and II were injected with 5 and 10 mg kg-1 of melatonin, and group III was injected with an isotonic NaCl solution. Group IV was injected with only 5 mg kg-1 of melatonin. Group V was reserved as a sham control. Following a 30-min-period, 6.0 Gy TBI was given to groups 1, 2 and 3 in a single fraction. The liver malondialdehyde (MDA) levels, super oxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were measured in all groups. TBI resulted in a significant increase in the liver tissue MDA levels and a decrease of SOD and GSH-Px activities. The results demonstrated that the liver tissue MDA levels in irradiated rats that were pretreated with melatonin (5 or 10 mg kg-1) were significantly decreased, while the SOD and GSH-Px activities were significantly increased. Decreasing the MDA levels by melatonin was dose dependent, but the liver tissue SOD and GSH activities were not. The data obtained in this study suggest that melatonin administration prior to irradiation may prevent liver damage by irradiation. (author)

289

Peripheral and Central Effects of Melatonin on Blood Pressure Regulation  

Science.gov (United States)

The pineal hormone, melatonin (N-acetyl-5-methoxytryptamine), shows potent receptor-dependent and -independent actions, which participate in blood pressure regulation. The antihypertensive effect of melatonin was demonstrated in experimental and clinical hypertension. Receptor-dependent effects are mediated predominantly through MT1 and MT2 G-protein coupled receptors. The pleiotropic receptor-independent effects of melatonin with a possible impact on blood pressure involve the reactive oxygen species (ROS) scavenging nature, activation and over-expression of several antioxidant enzymes or their protection from oxidative damage and the ability to increase the efficiency of the mitochondrial electron transport chain. Besides the interaction with the vascular system, this indolamine may exert part of its antihypertensive action through its interaction with the central nervous system (CNS). The imbalance between the sympathetic and parasympathetic vegetative system is an important pathophysiological disorder and therapeutic target in hypertension. Melatonin is protective in CNS on several different levels: It reduces free radical burden, improves endothelial dysfunction, reduces inflammation and shifts the balance between the sympathetic and parasympathetic system in favor of the parasympathetic system. The increased level of serum melatonin observed in some types of hypertension may be a counter-regulatory adaptive mechanism against the sympathetic overstimulation. Since melatonin acts favorably on different levels of hypertension, including organ protection and with minimal side effects, it could become regularly involved in the struggle against this widespread cardiovascular pathology. PMID:25299692

Pechanova, Olga; Paulis, Ludovit; Simko, Fedor

2014-01-01

290

Immune stimulation by exogenous melatonin during experimental endotoxemia.  

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Melatonin has been shown to enhance the immune response under immune-compromised conditions. However, its immune-modulatory effects under inflammatory conditions are unclear at present. Both pro- and anti-inflammation has been reported. To study time-dependent effects of melatonin on the general immune response during endotoxemia in more detail, we used two models in male rats: per-acute endotoxemia was induced by lipopolysaccharide (LPS) bolus injection (2.5 mg/kg), sub-acute endotoxemia by LPS infusion (2.5 mg/kg × h). Melatonin was applied directly before and 2 h after LPS administration (3 mg/kg, each). The LPS-induced formation of the pro-inflammatory cytokines tumor necrosis factor alpha, interferon-gamma, interleukin (IL)-1?/?, IL-5, and IL-6 and of the anti-inflammatory cytokine IL-10 was further amplified by melatonin, although it was only significant during per-acute endotoxemia. In both models, melatonin had no effect on the LPS-induced nitric oxide release. These findings show that exogenous melatonin is capable of enhancing the general immune response under inflammatory conditions. PMID:24385237

Effenberger-Neidnicht, Katharina; Brencher, Lisa; Broecker-Preuss, Martina; Hamburger, Tim; Petrat, Frank; de Groot, Herbert

2014-06-01

291

Management of tinnitus: oral treatment with melatonin and sulodexide.  

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The main problem arising from tinnitus is the disturbance it causes in day-to-day life and disturbance in sleep leading to fatigue and general discomfort. We attempted to study the effect of melatonin in conjunction with Sulodexide as a treatment method for tinnitus and evaluate its effectiveness. We studied 102 patients suffering from tinnitus with a Prospective Randomised Controlled Study conducted in a tertiary care ENT department. After randomisation, 34 patients were treated with melatonin and Sulodexide, another 34 were treated with melatonin alone, and the remaining 34 (control group) were managed without therapy in order to evaluate spontaneous variations in quality of tinnitus. Patients were assessed prospectively with Tinnitus Handicap Inventory and Acufenometry both pre-treatment and post-treatment. Among the patients we studied, we found better results with both Tinnitus Handicap Inventory and Acufenometry in the group who received melatonin and Sulodexide as against melatonin alone. Any improvement was noted in the control group. In conclusion, our opinion is that melatonin in combination with Sulodexide is a viable treatment option for patients suffering from central or sensorineural tinnitus. PMID:19589291

Neri, G; Baffa, C; De Stefano, A; Poliandri, A; Kulamarva, G; Di Giovanni, P; Petrucci, A G; Castriotta, A; Citraro, L; Cerrone, D; D' Orazio, F; Croce, A

2009-01-01

292

Wound healing and the effect of pineal gland and melatonin  

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Full Text Available Wound healing is a complex phenomenon that is controlled by local and general regulatory mechanisms. The aim of the paper is to analyze recently-published data devoted to the regulation of wound repair by melatonin. The effect of melatonin has been reported in different wound types healed with various mechanisms. The action of the pineal indoleamine is dependent on the used dose, time of application and target organ. Moreover, melatonin influences different phases of wound repair such as inflammation, by regulating the release of inflammatory mediators, cell proliferation and migration, by influencing angiogenesis, and the proliferation of fibroblasts, as well as the synthesis phase, by regulating collagen and glycosaminoglycan accumulation in the wounded milieu. Thus, healing of the skin wound, myocardial infarction, bone fractures and gastric ulcer is influenced by melatonin. In patients with low levels of melatonin (elderly or ?-blocker treated patients, its regulatory effects are expected to be impaired. Thus, the need for melatonin supplementation in those patients is postulated in the study. [J Exp Integr Med 2012; 2(1.000: 3-14

Jacek Drobnik

2012-02-01

293

Pineal melatonin synthesis in Syrian hamsters: A summary  

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During the past decade there has been ample documentation of the proposition that the pineal gland mediates photoperiodic influences upon reproductive behavior of hamsters. It is commonly hypothesized that the pineal gland expresses its activity by transformation of photoperiodic information into an hormonal output, that hormone being melatonin. If this hypothesis is correct, there must be some essential diffrence in melatonin's output when hamsters are exposed to different photoperiodic environments. The experiments summarized in this communication analyze pineal melatonin contents in Syrian hamsters maintained in a variety of photoperiodic conditions during different physiological states. The results demonstrate that adult hamsters have a daily surge in pineal melatonin content throughout their lifetime when exposed to simulated annual photoperiodic cycles. There is some fluctuation in the amount of pineal melatonin produced during different physiological states and photoperiodic environments, but these fluctuations seem small when compared to those normally found for other regulatory hormones. When hamsters are exposed to different photoperiodic regimens, the daily melatonin surge maintains a relatively constant phase relationship with respect to the onset of daily activity. There is a concomitant change in its phase relationship with respect to light-dark transitions.

Rollag, M. D.

1982-12-01

294

Melatonin as potential inducer of Th17 cell differentiation.  

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The subset of T lymphocytes producing IL-17 (Th17) plays a key role in the immune system. It has been implicated in host defense, inflammatory diseases, tumorigenesis, autoimmune diseases, and transplant rejection. Careful analysis of the data available holds that Th17 cell subpopulation should be under the direct control of pineal hormone melatonin: the key Th17 differentiation factor ROR? serves in the meantime as a high-affinity melatonin receptor. Since the levels of melatonin have diurnal and seasonal variation, as well as substantial deviations in some physiological or pathological conditions, melatonin-dependent regulation of Th17 cells should implicate multiform manifestation, such as influencing the outcome of infectious challenge or determining predisposition, etiology and progression of immune-related morbidities. Another important reason to raise a point of the new melatonin effects is current considering the possibilities of its clinical trials. Especially, the differentiation of Th17 upon melatonin treatment must aggravate the current recession in autoimmune diseases or induce serious complications in pregnancy. PMID:25064379

Kuklina, Elena M

2014-09-01

295

How significant is nocturnal sap flow?  

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Nocturnal sap flow (Qn) has been found to occur across many taxa, seasons and biomes. There is no general understanding as to how much Qn occurs and whether it is a significant contribution to total daily sap flow (Q). A synthesis of the literature and unpublished data was made to determine how significant is Qn, as a proportion of Q (%Qn), across seasons, biomes, phylogenetic groups and different thermometric sap flow methods. A total of 98 species were analysed to find that %Qn, on average, was 12.03% with the highest average dataset of 69.00%. There was significantly less %Qn in winter than in other temperate seasons, and significantly less %Qn in the wet season than in the dry season. The equatorial and tropical biomes had significantly higher %Qn than the warm temperate and nemoral biomes. The heat ratio method (HRM) and the thermal dissipation (TDP) method had significantly higher %Qn than the heat balance method. Additional analysis between HRM and TDP found HRM to have significantly higher %Qn in winter, wet season and various biomes. In all but one out of 246 cases Qn occurred, demonstrating that Qn is significant and needs to be carefully considered in sap flow and related studies. PMID:24990866

Forster, Michael A

2014-07-01

296

Laboratory tests for paroxysmal nocturnal hemoglobinuria.  

Science.gov (United States)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder that is often suspected in a patient presenting with non-immune hemolytic anemia associated with pancytopenia or venous thrombosis. This disorder is a consequence of acquired somatic mutations in the phosphatidylinositol glycan class A (PIG-A) gene in the hematopoietic stem cells (HSC) of patients. The presence of these mutations leads to production of blood cells with decreased glycosyl phosphatidylinositol-anchored cell surface proteins, making red blood cells derived from the clone more sensitive to complement mediated hemolysis. The diagnosis of PNH may be difficult in some cases due a low proportion of PNH cells in the blood and occasionally due to difficulties in selecting the most appropriate diagnostic studies. The latest generation of tests allow for detection of very small populations of PNH cells, for following the natural course and response to therapy of the disease, and for helping to decide when to initiate therapy with monoclonal antibody targeting the terminal complement protein C5 (Eculizumab), anticoagulation, and in some cases allogeneic HSC transplant. In this article, we review the different diagnostic tests available to clinicians for PNH diagnosis. PMID:24127129

Preis, Meir; Lowrey, Christopher H

2014-03-01

297

Efectos de la melatonina sobre la macro-arquitectura del sueño en pacientes con demencia tipo Alzheimer / Melatonin effects on macro arquitecture sleep in Alzheimer's disease patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish El objetivo del presente estudio fue determinar los efectos de 5 mg. de melatonina de liberación inmediata sobre la macro-arquitectura del sueño en ocho pacientes con diagnóstico de Demencia Tipo Alzheimer (DTA) de media a moderada. Utilizando la técnica polisomnográfica (PSG) se realizó un estudio [...] simple ciego, no aleatorio, controlado con placebo. Los registros PSG se llevaron a cabo de la siguiente manera: Noche 1: administración de placebo; noche 2 y 3: administración continua de melatonina (5 mg). Observamos que el tratamiento con melatonina durante la primera noche de administración disminuyó significativamente la latencia de la fase 2, del sueño de ondas delta y el sueño de MOR al ser comparadas con el placebo (P ?.05). No se observaron diferencias significativas en el tiempo total de cada fase de sueño; tampoco se observaron diferencias en la eficiencia del sueño en presencia de la melatonina. Sin embargo se observó una tendencia a la disminución del tiempo total de vigilia y un aumento del tiempo total de sueño, principalmente durante la segunda noche de tratamiento. Concluimos que la melatonina puede mejorar el sueño en pacientes con DTA de media a moderada. Abstract in english The objective of the present study was to evaluate the 5 mg. melatonin effects on the sleep macro-architecture in eight patients with middle to moderate Alzheimer's disease (DTA). Using the polysomnography technique (PSG), we made a simple-blind, non-randomized, controlled with placebo study. The PS [...] G was carried out according to the following order: night 1: placebo administration; night 2 and 3: continues melatonin administration. In the first night with melatonin treatment, the sleep latency to the first episode of Stage 2, Delta and REM sleep, was significantly diminished as compared with placebo (?.05). No significant difference in total time of each sleep stage and sleep efficiency was observed. Nevertheless, a tendency to diminish the total time of nocturnal wake and increase of the total sleep time in the second night with melatonin treatment was observed. We conclude that melatonin can improve sleep in patients with middle to moderate DTA.

Manuel Alejandro, Cruz-Aguilar; Ignacio, Ramírez-Salado; Carlos, Cruz-Ulloa; Gloria, Benítez-King.

298

Efectos de la melatonina sobre la macro-arquitectura del sueño en pacientes con demencia tipo Alzheimer / Melatonin effects on macro arquitecture sleep in Alzheimer's disease patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish El objetivo del presente estudio fue determinar los efectos de 5 mg. de melatonina de liberación inmediata sobre la macro-arquitectura del sueño en ocho pacientes con diagnóstico de Demencia Tipo Alzheimer (DTA) de media a moderada. Utilizando la técnica polisomnográfica (PSG) se realizó un estudio [...] simple ciego, no aleatorio, controlado con placebo. Los registros PSG se llevaron a cabo de la siguiente manera: Noche 1: administración de placebo; noche 2 y 3: administración continua de melatonina (5 mg). Observamos que el tratamiento con melatonina durante la primera noche de administración disminuyó significativamente la latencia de la fase 2, del sueño de ondas delta y el sueño de MOR al ser comparadas con el placebo (P ?.05). No se observaron diferencias significativas en el tiempo total de cada fase de sueño; tampoco se observaron diferencias en la eficiencia del sueño en presencia de la melatonina. Sin embargo se observó una tendencia a la disminución del tiempo total de vigilia y un aumento del tiempo total de sueño, principalmente durante la segunda noche de tratamiento. Concluimos que la melatonina puede mejorar el sueño en pacientes con DTA de media a moderada. Abstract in english The objective of the present study was to evaluate the 5 mg. melatonin effects on the sleep macro-architecture in eight patients with middle to moderate Alzheimer's disease (DTA). Using the polysomnography technique (PSG), we made a simple-blind, non-randomized, controlled with placebo study. The PS [...] G was carried out according to the following order: night 1: placebo administration; night 2 and 3: continues melatonin administration. In the first night with melatonin treatment, the sleep latency to the first episode of Stage 2, Delta and REM sleep, was significantly diminished as compared with placebo (?.05). No significant difference in total time of each sleep stage and sleep efficiency was observed. Nevertheless, a tendency to diminish the total time of nocturnal wake and increase of the total sleep time in the second night with melatonin treatment was observed. We conclude that melatonin can improve sleep in patients with middle to moderate DTA.

Manuel Alejandro, Cruz-Aguilar; Ignacio, Ramírez-Salado; Carlos, Cruz-Ulloa; Gloria, Benítez-King.

2013-08-01

299

Prediction of melatonin efficacy by pretreatment dim light melatonin onset in children with idiopathic chronic sleep onset insomnia.  

Science.gov (United States)

Research has shown efficacy of melatonin treatment to advance sleep-wake rhythms in insomnia. In healthy adults, direction and magnitude of the phase shift depends on the timing of administration relative to the phase position of the circadian system. Therefore, in the present study we investigated whether in children with chronic sleep onset insomnia (SOI) efficacy of melatonin treatment in the early evening could be predicted from dim light melatonin onset (DLMO), a phase marker of the circadian system. We combined data of two previously published double blind, randomized, placebo-controlled trials in 110 participants, aged 6-12 years. Sleep was actigraphically estimated, and saliva collected, at baseline and in the third week of a 4-week treatment period with 5 mg melatonin or placebo at 18:00 or 19:00 hours. Primary outcome measures were pre- to post-treatment changes in dim light melatonin onset (DeltaDLMO), sleep onset (DeltaSO), sleep latency (DeltaSL), and total sleep duration (DeltaTSD). Melatonin advanced DLMO with +1:12 h (P DLMO was significantly related to DeltaDLMO [F(1, 29) = 7.28, P = 0.012] and DeltaSO [F(1, 25) = 7.72, P = 0.010]. The time interval between treatment administration and pretreatment DLMO (INT) was only significantly related to DeltaSO [F(1,26) = 5.40, P = 0.028]. The results suggest that in children with SOI, the efficacy of early evening melatonin to advance sleep onset and endogenous melatonin onset increases the later the pretreatment DLMO is. PMID:15910516

van der Heijden, Kristiaan B; Smits, Marcel G; van Someren, Eus J W; Boudewijn Gunning, W

2005-06-01

300

Melatonin suppresses markers of inflammation and oxidative damage in a human daytime endotoxemia model  

DEFF Research Database (Denmark)

Melatonin used as an exogenous drug has been documented to have potent antioxidant and anti-inflammatory effects in animal model. We aimed to examine the effect of melatonin in an experimental human sepsis model.

Alamili, Mahdi; Bendtzen, Klaus

2014-01-01

 
 
 
 
301

A one step synthesis of ring labelled melatonin-3H with high specific activity  

International Nuclear Information System (INIS)

A mixture of brominated melatonin derivatives has been synthesized for use as starting material for preparation of ring tritium labelled melatonin by catalytic hydrogenolysis. The high specific activity obtained makes this product useful in radioimmunoassay studies. (author)

302

Melatonin in children with autism spectrum disorders: endogenous and pharmacokinetic profiles in relation to sleep.  

Science.gov (United States)

Supplemental melatonin has been used to treat sleep onset insomnia in children with autism spectrum disorders (ASD), although the mechanism of action is uncertain. We assessed endogenous and supplemental melatonin profiles in relation to sleep in nine children with ASD. In endogenous samples, maximal melatonin concentration (C max) and time to peak concentration (T max) were comparable to those previously published in the literature for typically developing children, and dim light melatonin onsets were captured in the majority of children. In treatment samples (supplemental melatonin), melatonin parameters were also comparable to those previously published for typically developing children. Our findings support that children with ASD and insomnia responsive to low dose melatonin treatment have relatively normal profiles of endogenous and supplemental melatonin. PMID:24752680

Goldman, Suzanne E; Adkins, Karen W; Calcutt, M Wade; Carter, Melissa D; Goodpaster, Robert L; Wang, Lily; Shi, Yaping; Burgess, Helen J; Hachey, David L; Malow, Beth A

2014-10-01

303

Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry  

International Nuclear Information System (INIS)

Melatonin, the chief hormone of the pineal gland in vertebrates, is widely distributed in the animal kingdom. Among many functions, melatonin synchronizes circadian and circannual rhythms, stimulates immune function, may increase life span, inhibits growth of cancer cells in vitro and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl radicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin, in varying concentrations, is also found in a variety of plants. Melatonin concentrations, measured in nine different plants by radioimmunoassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our findings suggest that the consumption of plant materials that contain high levels of melatonin could alter blood melatonin levels of the indole as well as provide protection of macromolecules against oxidative damage. (au) 30 refs

304

Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry  

Energy Technology Data Exchange (ETDEWEB)

Melatonin, the chief hormone of the pineal gland in vertebrates, is widely distributed in the animal kingdom. Among many functions, melatonin synchronizes circadian and circannual rhythms, stimulates immune function, may increase life span, inhibits growth of cancer cells in vitro and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl radicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin, in varying concentrations, is also found in a variety of plants. Melatonin concentrations, measured in nine different plants by radioimmunoassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our findings suggest that the consumption of plant materials that contain high levels of melatonin could alter blood melatonin levels of the indole as well as provide protection of macromolecules against oxidative damage. (au) 30 refs.

Dubbels, R.; Klenke, E.; Schnakenberg, E.; Ehlers, C.; Schloot, W. [Univ. of Bremen, Center of Human Genetics and Genetic Counselling, Bremen (Germany); Reiter, R.J. [The Univ. of Texas Health Science Center at San Antonio, Dept. of Cellular and Structural Biology, San Antonio, Texas (United States); Goebel, A.; Schiware, H.W. [Gemeinschaftslabor Dr. Schiwara et al., Breman (Germany)

1995-01-01

305

Scientific Basis for the Potential Use of Melatonin in Bone Diseases: Osteoporosis and Adolescent Idiopathic Scoliosis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this paper was to analyze the data supporting the possible role of melatonin on bone metabolism and its repercussion in the etiology and treatment of bone pathologies such as the osteoporosis and the adolescent idiopathic scoliosis (AIS). Melatonin may prevent bone degradation and promote bone formation through mechanisms involving both melatonin receptor-mediated and receptor-independent actions. The three principal mechanisms of melatonin effects on bone function could be: ...

Reiter, R. J.; Tan, D. X.; Mediavilla, M. D.; Amp Nchez-barcel Amp, E. J. S.

2010-01-01

306

Seasonal changes in circadian peripheral plasma concentrations of melatonin, serotonin, dopamine and cortisol in aged horses with Cushing's disease under natural photoperiod.  

Science.gov (United States)

Equine pituitary pars intermedia dysfunction (PPID) is a common and serious condition that gives rise to Cushing's disease. In the older horse, it results in hyperadrenocorticism and disrupted energy metabolism, the severity of which varies with the time of year. To gain insight into the mechanism of its pathogenesis, 24-h profiles for peripheral plasma melatonin, serotonin, dopamine and cortisol concentrations were determined at the winter and summer solstices, and the autumn and spring equinoxes in six horses diagnosed with Cushing's disease and six matched controls. The nocturnal rises in plasma melatonin concentrations, although different across seasons, were broadly of the same duration and similar amplitude in both groups of animals (P > 0.05). The plasma concentrations of cortisol did not show seasonal variation and were different in diseased horses only in the summer when they were higher across the entire 24-h period (P Cushing's group in the summer and autumn (P Cushing's syndrome is an unlikely reason for the disease. In addition, the results provide evidence that alterations in the dopaminergic and serotoninergic systems may participate in the pathogenesis of PPID. PMID:18540997

Haritou, S J A; Zylstra, R; Ralli, C; Turner, S; Tortonese, D J

2008-08-01

307

Health effects of extremely low-frequency magnetic fields: reconsidering the melatonin hypothesis in the light of current data on magnetoreception.  

Science.gov (United States)

The so-called 'Melatonin Hypothesis' proposed that decreased nocturnal production of melatonin (MLT) might explain the increased risk of breast cancer that has been formerly attributed to extremely low-frequency (ELF) magnetic fields (MF) of weak intensity. Although the risk of ELF MF upon breast cancer was later dismissed, repeated reports were published of partial inhibition of MLT secretion in rats under long-term (? 4 weeks) exposure to weak ELF MF. Since 2004, however, this topic has not been experimentally studied any more. In the present study, we propose to go back to the MLT hypothesis and apply it to childhood leukemia, for which an increased risk has been robustly associated with residential exposure to ELF MF. Contrary to the original hypothesis, however, we do not consider decreased MLT levels, but disruption of circadian rhythmicity per se as the effector mechanism. Indeed, the role of the circadian timing system in the development of childhood leukemia has been well established. Motivation for going back to the MLT hypothesis comes from recent data that suggest magnetosensory disruption by ELF MF in mammals, and magnetosensitivity in humans, together with current evidence for an influence on circadian rhythmicity from disruption of non-photic sensory stimuli of various natures. We thus suggest further study on circadian rhythmicity in humans (children if possible) under long-term exposure to weak ELF MF. PMID:22696437

Vanderstraeten, Jacques; Verschaeve, Luc; Burda, Hynek; Bouland, Catherine; de Brouwer, Christophe

2012-12-01

308

Impact of photoperiod manipulation on day/night changes in melatonin, sex steroids and vitellogenin plasma levels and spawning rhythms in Senegal sole, Solea senegalensis.  

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Photoperiod and temperature are known as the main synchronizers of seasonal reproduction in fish. This paper studied the role of photoperiod on the synchronization of F1 Senegal sole reproduction rhythms. Fish were maintained under constant short-photoperiod (9L:15D) from the winter solstice onwards (experimental group) or under naturally-changing photoperiod (control group), and water temperature naturally oscillated in both groups. Blood samples were collected during the reproduction season at pre-spawning (March), spawning (April) and post-spawning (May) to determine the endocrine status. Spawning events and egg quality parameters were also monitored. The results revealed a significant increase in nocturnal melatonin concentration from March to May in the control group, while in the experimental group such seasonal change did not occur. As to plasma levels of vitellogenin, testosterone, estradiol and 11keto-testosterone, differences between groups were found mostly in March, while in April and May levels were often similar. Spawning was observed in both groups, although the experimental group started slightly earlier and also finished earlier than the control group, perhaps as a result of the increase in sex steroids and VTG observed at pre-spawning. Briefly, reproduction rhythms persisted in the absence of the natural lengthening of photoperiod, although photoperiod manipulation altered the seasonal modulation of melatonin, increased sex steroids and vitellogenin at pre-spawning, and slightly advanced the timing of spawning. PMID:21466857

Oliveira, Catarina; Mañanós, Evaristo; Ramos, Jesus; Sánchez-Vázquez, Francisco Javier

2011-07-01

309

Direct fluorination of melatonin and 5-hydroxy-L-tryptophan with [18F]F2  

International Nuclear Information System (INIS)

In order that melatonin receptors may be studied in man with positron emission tomography, melatonin labelled with a positron emitting isotope is needed. The preparation of 6-fluoro-melatonin labelled with F-18 is described. Using the same fluorination method, 5-hydroxy-6-(F-18)fluorotryptophan and 4-(F-18)fluoro-5-hydroxy-tryptophan were also prepared. (UK)

310

Melatonin in Children with Autism Spectrum Disorders: Endogenous and Pharmacokinetic Profiles in Relation to Sleep  

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Supplemental melatonin has been used to treat sleep onset insomnia in children with autism spectrum disorders (ASD), although the mechanism of action is uncertain. We assessed endogenous and supplemental melatonin profiles in relation to sleep in nine children with ASD. In endogenous samples, maximal melatonin concentration (C[subscript max]) and…

Goldman, Suzanne E.; Adkins, Karen W.; Calcutt, M. Wade; Carter, Melissa D.; Goodpaster, Robert L.; Wang, Lily; Shi, Yaping; Burgess, Helen J.; Hachey, David L.; Malow, Beth A.

2014-01-01

311

Nocturnal asthma in school children of south punjab, pakistan  

International Nuclear Information System (INIS)

At the present time, the epidemiology of the childhood asthma is of considerable interest. There is an understandable concern that changes in the geographical area, lifestyle, and environment. This study was conducted to find the prevalence of nocturnal asthma, in school children of south Punjab, Pakistan. It was a cross sectional, questionnaire based, descriptive survey of the children aged 3-18 years, in randomly selected primary and secondary schools, from October 2002 to March 2003. The data was analysed with Statistical Analysis System (SAS). Of 6120 questionnaire sent to the parents/guardians, we received 3180 back (52%). Of the 3180 respondents, 1767 (56%) were for boys and 1413 (44%) were for girls. The median age was 8.25 years. Around 71% of children were between 4 to 11 years of age. The parents reported nocturnal asthma in 177 (6%) of their children with an equal prevalence in boys and girls, i.e., (3% each, rounded off to nearest whole number). Of these 177 children with nocturnal asthma, 99 (56%) were boys and 78 (44%) were girls. Of the 1767 boys and 1413 girls, the nocturnal asthma reported by parents was 6% each (99 and 78 respectively). The nocturnal asthma was not reported in 14-18 years age group of females. The asthma is taken as a stigma in our society and as such is not reported or disclosed rather denied. An extensive educational media campaign is required for awareness of the masses. (author)

312

Paroxysmal nocturnal hemoglobinuria in systemic lupus erythematosus: a case report  

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Full Text Available Abstract Introduction Paroxysmal nocturnal hemoglobinuria is an acquired disorder of hemopoiesis and is characterized by recurrent episodes of intravascular hemolysis due to an increased sensitivity to complement-mediated hemolysis. Systemic lupus erythematosus with paroxysmal nocturnal hemoglobinuria is very rare. We report a case of paroxysmal nocturnal hemoglobinuria that developed in a patient with systemic lupus erythematosus and lupus nephritis. Case presentation A 29-year-old Mongolian woman had systemic lupus erythematosus, which manifested only as skin lesions when she was 12 years old. She had leg edema and proteinuria when she was 23 years old, and a renal biopsy revealed lupus nephritis (World Health Organization type IV. She had been treated with steroids and immunosuppressant therapy. At 29, she had headaches, nausea, general fatigue, and severe pancytopenia and was admitted to our hospital. A laboratory evaluation showed hemolytic anemia. Further examination showed a neutrophil alkaline phosphatase score of 46 points, a CD55 value of 18%, and a CD59 value of 78.6%. The results of Ham test and sugar water tests were positive. The constellation of symptoms throughout the clinical course and the laboratory findings suggested paroxysmal nocturnal hemoglobinuria. Conclusions To the best of our knowledge, systemic lupus erythematosus with paroxysmal nocturnal hemoglobinuria is very rare. Clinicians should be aware of the association between autoimmune and hematological diseases.

Nakamura Norio

2011-11-01

313

Diurnal Profiles of Melatonin Synthesis-Related Indoles, Catecholamines and Their Metabolites in the Duck Pineal Organ  

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Full Text Available This study characterizes the diurnal profiles of ten melatonin synthesis-related indoles, the quantitative relations between these compounds, and daily variations in the contents of catecholamines and their metabolites in the domestic duck pineal organ. Fourteen-week-old birds, which were reared under a 12L:12D cycle, were killed at two-hour intervals. The indole contents were measured using HPLC with fluorescence detection, whereas the levels of catecholamines and their metabolites were measured using HPLC with electrochemical detection. All indole contents, except for tryptophan, showed significant diurnal variations. The 5-hydroxytryptophan level was approximately two-fold higher during the scotophase than during the photophase. The serotonin content increased during the first half of the photophase, remained elevated for approximately 10 h and then rapidly decreased in the middle of the scotophase. N-acetylserotonin showed the most prominent changes, with a more than 15-fold increase at night. The melatonin cycle demonstrated only an approximately 5-fold difference between the peak and nadir. The 5-methoxytryptamine content was markedly elevated during the scotophase. The 5-hydroxyindole acetic acid, 5-hydroxytryptophol, 5-methoxyindole acetic acid and 5-methoxytryptophol profiles were analogous to the serotonin rhythm. The norepinephrine and dopamine contents showed no significant changes. The DOPA, DOPAC and homovanillic acid levels were higher during the scotophase than during the photophase. Vanillylmandelic acid showed the opposite rhythm, with an elevated level during the daytime.

Bogdan Lewczuk

2014-07-01

314

Monocular Elevation Deficiency - Double Elevator Palsy  

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... Español Condiciones Chinese Conditions Monocular Elevation Deficiency/ Double Elevator Palsy En Español Read in Chinese What is ... is the cause of Monocular Elevation Deficiency (Double Elevator Palsy)? The restriction to elevate the eye can ...

315

Effect of topical application of melatonin to the gingiva on salivary osteoprotegerin, RANKL and melatonin levels in patients with diabetes and periodontal disease.  

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This cross-section study was designed to assess the effect of topical application of melatonin to the gingiva on salivary RANKL, osteoprotegrin (OPG) and melatonin levels as well as plasma melatonin in 30 patients with diabetes and periodontal disease and in a control group of 30 healthy subjects. Salivary RANKL and OPG were measured by enzyme-linked immunosorbent assay and salivary and plasma melatonin by radioimmunoassay using commercial kits. Periodontograms were performed using the Florida Probe(®). Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days. Patients with diabetes showed significantly higher mean levels of salivary RANKL than healthy subjects as well as significantly lower values of salivary OPG and salivary and plasma melatonin. After treatment with melatonin, there was a statistically significant decrease of the gingival index, pocket depth and salivary levels of RANKL, and a significant rise in salivary values of OPG. Changes of salivary OPG levels before and after topical melatonin treatment correlated significantly with changes in the gingival index and pocket depth. Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of RANKL and increase in salivary concentrations of OPG, which indicates that melatonin has a favorable effect in slowing osteoclastogenesis, improving the quality of alveolar bone and preventing the progression of periodontal disease. PMID:23934086

Cutando, Antonio; López-Valverde, Antonio; de Diego, Rafael Gómez; de Vicente, Joaquín; Reiter, Russell; Fernández, María Herrero; Ferrera, María José

2014-07-01

316

Melatonina y deficiencia de hormona de crecimiento: contribucin a la evaluacin de los desrdenes neuroendocrinos Melatonin and growth hormone deficiency: a contribution to the evaluation of neuroendocrine disorders  

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Full Text Available La melatonina constituye un integrante fundamental del denominado "reloj biolgico" y las alteraciones hormonales sueo-dependientes. Siendo la secrecin fisiolgica de GH, predominantemente nocturna, evaluamos en un grupo de nios y adultos deficitarios de GH (GHD sin y con tratamiento sustitutivo, la secrecin nocturna de melatonina. Estudiamos 44 pacientes GHD: Grupo a (Ga: Nios sin tratamiento; Grupo b (Gb: Nios con tratamiento con GH (0.16 mg/Kg/semana, dosis estable por mnimo de 6 meses; Grupo c (Gc: Adultos sin tratamiento y Grupo d (Gd: Adultos con tratamiento con GH (0.1- 0.8 mg/da, para mantener IGF1 entre 0 y +2 SDS, dosis estable por mnimo de 6 meses. Todos los pacientes con dficits hormonales asociados estaban adecuadamente sustituidos. La produccin de melatonina fue evaluada a travs de la medicin de su principal metabolito urinario: 6-Sulfatoximelatonina (6-SM, dosado por radioinmunoensayo, en muestras nocturnas (6PM a 8AM. Los niveles de 6-SM nocturna expresados como ?g/unidad de tiempo fueron (media SEM para el grupo peditrico: Ga = 6.50 ( 5.10 y Gb = 8.21 ( 5.31 (Test de Mann-Whitney, p = 0.82. Para los adultos fueron: Gc = 2.99 ( 1.17 y Gd = 6.60 ( 2.00 (Test de Mann-Whitney, p = 0.35. En algunas alteraciones hipotlamo-hipofisarias han sido descriptas modificaciones del patrn secretorio de melatonina, pero no se han caracterizado en forma completa an, las posibles variaciones en pacientes con GHD. Si bien en las condiciones de este estudio, no hallamos diferencias en la excrecin nocturna de 6-SM entre los GHD no tratados y los tratados en ambos grupos, ello no invalida la existencia de posibles diferencias que podran detectarse estudiando la secrecin diurna de melatonina y su diferencia con la secrecin nocturna. Todo ello podr contribuir al conocimiento de los posibles desrdenes cronobiolgicos involucrados en la deficiencia de GH.Melatonin, a hormone secreted by the pineal gland, constitutes a landmark in neuroendocrine integration. The relationship between melatonin and different pituitary hormones and sex steroids has been studied; however, the relationship between growth hormone (GH and melatonin remains unclear. Considering that melatonin is an essential component of the so-called "biological clock", related to circadian rhythm, day-night cycle, and sleep-dependent hormonal alterations, and knowing that physiological GH secretion occurs predominantly at night, we decided to evaluate nocturnal melatonin secretion in a group of GH-deficient children and adults on and off replacement therapy. Patients and Methods: We studied 44 patients with GH deficiency (GHD, duly confirmed by pharmacological tests, divided into 4 groups: Group a (Ga : untreated GHD children; Group b (Gb: GHD children on GH replacement therapy (0.16 mg/Kg/week, stable dose for at least 6 months; Group c (Gc: untreated GHD adults and Group d (Gd: GHD adults on GH replacement therapy (0.1- 0.8 mg/day, to maintain IGF1 between 0 and +2 SDS, stable dose for at least 6 months. All associated hormonal deficits were adequately replaced. Melatonin production was evaluated by measuring the excretion of its major urinary metabolite: 6-Sulphatoxymelatonin (6-SM. Urinary 6-SM was measured (radioimmunoassay, Stockgrand Ltd, Guildford, UK in nocturnal samples (6PM to 8AM in all patients. Results: Nocturnal 6-SM levels expressed as ?g/unit of time were (mean SEM for the pediatric group: Ga = 6.50 ( 5.10 and Gb = 8.21 ( 5.31 (Mann Whitney test, p = 0.82. For adults: Gc = 2.99 ( 1.17 and Gd = 6.60 ( 2.00 (Mann Whitney test, p = 0.35. Discussion and Conclusions: It is difficult to characterize the relationship between melatonin and GH in healthy individuals; however, the administration of intravenous melatonin stimulates GH secretion in normal adults. In some hypothalamic-pituitary alterations, changes in the secretory pattern of melatonin have been reported, but possible variations in GHD patients have not been thoroughly characterized yet. This led us to evaluate 6-SM concentrations in GH deficient children and adults on and

G Fideleff

2011-10-01

317

Melatonina y deficiencia de hormona de crecimiento: contribucin a la evaluacin de los desrdenes neuroendocrinos / Melatonin and growth hormone deficiency: a contribution to the evaluation of neuroendocrine disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish La melatonina constituye un integrante fundamental del denominado "reloj biolgico" y las alteraciones hormonales sueo-dependientes. Siendo la secrecin fisiolgica de GH, predominantemente nocturna, evaluamos en un grupo de nios y adultos deficitarios de GH (GHD) sin y con tratamiento sustitutivo, la [...] secrecin nocturna de melatonina. Estudiamos 44 pacientes GHD: Grupo a (Ga): Nios sin tratamiento; Grupo b (Gb): Nios con tratamiento con GH (0.16 mg/Kg/semana, dosis estable por mnimo de 6 meses); Grupo c (Gc): Adultos sin tratamiento y Grupo d (Gd): Adultos con tratamiento con GH (0.1- 0.8 mg/da, para mantener IGF1 entre 0 y +2 SDS, dosis estable por mnimo de 6 meses). Todos los pacientes con dficits hormonales asociados estaban adecuadamente sustituidos. La produccin de melatonina fue evaluada a travs de la medicin de su principal metabolito urinario: 6-Sulfatoximelatonina (6-SM), dosado por radioinmunoensayo, en muestras nocturnas (6PM a 8AM). Los niveles de 6-SM nocturna expresados como ?g/unidad de tiempo fueron (media SEM) para el grupo peditrico: Ga = 6.50 ( 5.10) y Gb = 8.21 ( 5.31) (Test de Mann-Whitney, p = 0.82). Para los adultos fueron: Gc = 2.99 ( 1.17) y Gd = 6.60 ( 2.00) (Test de Mann-Whitney, p = 0.35). En algunas alteraciones hipotlamo-hipofisarias han sido descriptas modificaciones del patrn secretorio de melatonina, pero no se han caracterizado en forma completa an, las posibles variaciones en pacientes con GHD. Si bien en las condiciones de este estudio, no hallamos diferencias en la excrecin nocturna de 6-SM entre los GHD no tratados y los tratados en ambos grupos, ello no invalida la existencia de posibles diferencias que podran detectarse estudiando la secrecin diurna de melatonina y su diferencia con la secrecin nocturna. Todo ello podr contribuir al conocimiento de los posibles desrdenes cronobiolgicos involucrados en la deficiencia de GH. Abstract in english Melatonin, a hormone secreted by the pineal gland, constitutes a landmark in neuroendocrine integration. The relationship between melatonin and different pituitary hormones and sex steroids has been studied; however, the relationship between growth hormone (GH) and melatonin remains unclear. Conside [...] ring that melatonin is an essential component of the so-called "biological clock", related to circadian rhythm, day-night cycle, and sleep-dependent hormonal alterations, and knowing that physiological GH secretion occurs predominantly at night, we decided to evaluate nocturnal melatonin secretion in a group of GH-deficient children and adults on and off replacement therapy. Patients and Methods: We studied 44 patients with GH deficiency (GHD), duly confirmed by pharmacological tests, divided into 4 groups: Group a (Ga ): untreated GHD children; Group b (Gb): GHD children on GH replacement therapy (0.16 mg/Kg/week, stable dose for at least 6 months); Group c (Gc): untreated GHD adults and Group d (Gd): GHD adults on GH replacement therapy (0.1- 0.8 mg/day, to maintain IGF1 between 0 and +2 SDS, stable dose for at least 6 months). All associated hormonal deficits were adequately replaced. Melatonin production was evaluated by measuring the excretion of its major urinary metabolite: 6-Sulphatoxymelatonin (6-SM). Urinary 6-SM was measured (radioimmunoassay, Stockgrand Ltd, Guildford, UK) in nocturnal samples (6PM to 8AM) in all patients. Results: Nocturnal 6-SM levels expressed as ?g/unit of time were (mean SEM) for the pediatric group: Ga = 6.50 ( 5.10) and Gb = 8.21 ( 5.31) (Mann Whitney test, p = 0.82). For adults: Gc = 2.99 ( 1.17) and Gd = 6.60 ( 2.00) (Mann Whitney test, p = 0.35). Discussion and Conclusions: It is difficult to characterize the relationship between melatonin and GH in healthy individuals; however, the administration of intravenous melatonin stimulates GH secretion in normal adults. In some hypothalamic-pituitary alterations, changes in the secretory pattern of melatonin have been reported, but possible variations in GHD patients have not been

G, Fideleff; M, Surez; HR, Boquete; M, Azaretzky; P, Sobrado; O, Brunetto; HL, Fideleff.

2011-10-01

318

Melatonina y deficiencia de hormona de crecimiento: contribucin a la evaluacin de los desrdenes neuroendocrinos / Melatonin and growth hormone deficiency: a contribution to the evaluation of neuroendocrine disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish La melatonina constituye un integrante fundamental del denominado "reloj biolgico" y las alteraciones hormonales sueo-dependientes. Siendo la secrecin fisiolgica de GH, predominantemente nocturna, evaluamos en un grupo de nios y adultos deficitarios de GH (GHD) sin y con tratamiento sustitutivo, la [...] secrecin nocturna de melatonina. Estudiamos 44 pacientes GHD: Grupo a (Ga): Nios sin tratamiento; Grupo b (Gb): Nios con tratamiento con GH (0.16 mg/Kg/semana, dosis estable por mnimo de 6 meses); Grupo c (Gc): Adultos sin tratamiento y Grupo d (Gd): Adultos con tratamiento con GH (0.1- 0.8 mg/da, para mantener IGF1 entre 0 y +2 SDS, dosis estable por mnimo de 6 meses). Todos los pacientes con dficits hormonales asociados estaban adecuadamente sustituidos. La produccin de melatonina fue evaluada a travs de la medicin de su principal metabolito urinario: 6-Sulfatoximelatonina (6-SM), dosado por radioinmunoensayo, en muestras nocturnas (6PM a 8AM). Los niveles de 6-SM nocturna expresados como ?g/unidad de tiempo fueron (media SEM) para el grupo peditrico: Ga = 6.50 ( 5.10) y Gb = 8.21 ( 5.31) (Test de Mann-Whitney, p = 0.82). Para los adultos fueron: Gc = 2.99 ( 1.17) y Gd = 6.60 ( 2.00) (Test de Mann-Whitney, p = 0.35). En algunas alteraciones hipotlamo-hipofisarias han sido descriptas modificaciones del patrn secretorio de melatonina, pero no se han caracterizado en forma completa an, las posibles variaciones en pacientes con GHD. Si bien en las condiciones de este estudio, no hallamos diferencias en la excrecin nocturna de 6-SM entre los GHD no tratados y los tratados en ambos grupos, ello no invalida la existencia de posibles diferencias que podran detectarse estudiando la secrecin diurna de melatonina y su diferencia con la secrecin nocturna. Todo ello podr contribuir al conocimiento de los posibles desrdenes cronobiolgicos involucrados en la deficiencia de GH. Abstract in english Melatonin, a hormone secreted by the pineal gland, constitutes a landmark in neuroendocrine integration. The relationship between melatonin and different pituitary hormones and sex steroids has been studied; however, the relationship between growth hormone (GH) and melatonin remains unclear. Conside [...] ring that melatonin is an essential component of the so-called "biological clock", related to circadian rhythm, day-night cycle, and sleep-dependent hormonal alterations, and knowing that physiological GH secretion occurs predominantly at night, we decided to evaluate nocturnal melatonin secretion in a group of GH-deficient children and adults on and off replacement therapy. Patients and Methods: We studied 44 patients with GH deficiency (GHD), duly confirmed by pharmacological tests, divided into 4 groups: Group a (Ga ): untreated GHD children; Group b (Gb): GHD children on GH replacement therapy (0.16 mg/Kg/week, stable dose for at least 6 months); Group c (Gc): untreated GHD adults and Group d (Gd): GHD adults on GH replacement therapy (0.1- 0.8 mg/day, to maintain IGF1 between 0 and +2 SDS, stable dose for at least 6 months). All associated hormonal deficits were adequately replaced. Melatonin production was evaluated by measuring the excretion of its major urinary metabolite: 6-Sulphatoxymelatonin (6-SM). Urinary 6-SM was measured (radioimmunoassay, Stockgrand Ltd, Guildford, UK) in nocturnal samples (6PM to 8AM) in all patients. Results: Nocturnal 6-SM levels expressed as ?g/unit of time were (mean SEM) for the pediatric group: Ga = 6.50 ( 5.10) and Gb = 8.21 ( 5.31) (Mann Whitney test, p = 0.82). For adults: Gc = 2.99 ( 1.17) and Gd = 6.60 ( 2.00) (Mann Whitney test, p = 0.35). Discussion and Conclusions: It is difficult to characterize the relationship between melatonin and GH in healthy individuals; however, the administration of intravenous melatonin stimulates GH secretion in normal adults. In some hypothalamic-pituitary alterations, changes in the secretory pattern of melatonin have been reported, but possible variations in GHD patients have not been

G, Fideleff; M, Surez; HR, Boquete; M, Azaretzky; P, Sobrado; O, Brunetto; HL, Fideleff.

319

Interactions of the platelets in paroxysmal nocturnal hemoglobinuria with complement. Relationship to defects in the regulation of complement and to platelet survival in vivo.  

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The blood cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) have abnormal interactions with complement. The activity of the alternative pathway C3 convertase on the platelets of 9 out of 19 patients with PNH was elevated. 10 patients had C3 convertase activity within the normal range even though 80-95% of their platelets lacked the complement regulatory protein decay accelerating factor (DAF) that is absent from the affected blood cells in PNH. PNH and normal platelets released...

Devine, D. V.; Siegel, R. S.; Rosse, W. F.

1987-01-01

320

Effects of melatonin on liver of rats with experimental hyperthyroid  

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Full Text Available The aim of this study was to investigate the structural changes that occurred in the liver of rats with experimental hyperthyroidism and the possible effects of melatonin on these changes. The animals were designated as control group (group I, 3,3', 5-Triiodo-I-Thyronine (T3 injected group (group II and T3+ melatonin injected group (group III. At the end of study, tissue specimens were examined for changes in structure. In the T3 injected group dilatation in sinusoids and pale cytoplasm were observed, as well as an increased number of the Kupffer cells and an increased amount of glycogen. In T3 + melatonin injected group, the amount of glycogen was similar to the T3 injected groups while the number of Kupffer cells increased but sinusoid largeness and hepatocyte structure were similar to the control. On electron microscopic examination the mitochondria of T3 injected group were slightly larger than those of the control group. In T3 + melatonin injected group enlargement in the spaces of Disse, increased number of lipid vacuoles of Ito cells and increased number of microvilli of hepatocytes were observed. Kupffer cells were more active in this group. The results of this study indicate that T3 injection causes structural changes in the liver, and melatonin hormone has a small, if any, protective effect on the liver of rats with hyperthyroid.

Oner J.

2005-01-01

 
 
 
 
321

ARE THE MELATONIN SUPPLEMENTS POTENTIAL TREATMENT OPTIONS? A SYSTEMATIC REVIEW  

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Full Text Available Introduction: Melatonin is a neuro-hormone secreted from the pineal gland and involved in various regulatory activities in body. Ever-increasing use of melatonin supplements and enlarging research evidences make the authors undertook the review to arrive at a qualitative conclusion whether melatonin supplements can act as potential treatment options or not.Methodology: A comprehensive search was undertaken in different electronic databases using various search terms. A total of 225 studies were identified including clinical research studies and basic experiments. Data were extracted individually from the studies and compiled in the end.Results: Melatonin has been used successfully in chronic insomnia and as an anti-oxidant in cancer and other age-related neuro-degenerative disorders, especially Alzheimer’s disease and Autistic disorders. Its evidences of use in other conditions remained insufficient and inconclusive.Conclusion: Melatonin therapy may be considered as efficacious and safe in insomnia and as an anti-oxidant; however, other roles needs to be evaluated in further studies.

Subhranil Saha*, Munmun Koley and Sandip Patra

2013-10-01

322

Melatonin, a possible promising panacea for premature ovarian failure  

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Full Text Available Premature ovarian failure (POF is characterized by impairment of ovarian function unrelated to elevatedfollicle-stimulating hormone (FSH before the age of 40. The consequence of POF is severe and distinctive, presentingfrom infertility to symptoms caused by hormone deprivation. The mechanism of POF remains unclearand current treatments are therefore ineffective. Melatonin (N-acetyl-5-methoxytryptamine is a neuroendocrinalhormone chiefly secreted by the pineal body. Melatonin exerts extensive physiological and pharmacologicaleffects on the biological rhythm, oxidative stress, reproduction, autoimmune and tumourigenesis. However,current researches have not yet brought melatonin into the study of POF. In the present review, we have involvedstate-of-the-art research progress of melatonin in ovary with regard to oxidation, follicle formation and function,and ovarian autoimmune disorders since these aspects mainly dispose to POF development. The features thatmelatonin scavenges reactive oxygen species (ROS, directly and indirectly induces follicle maturation, ovulationand inhibits apoptosis, and modulates autoimmune derangements in the ovaries are highly indicative that melatonincan effect in combating POF. Also, in this respect we have discussed the possibility of applying melatoninin the treatment of POF and have listed evidence of studies in vitro and in vivo. Vacant research directions aresubsequently suggested and the future application of melatonin in POF treatment is prospected.

Ting Guo

2011-04-01

323

Paroxysmal nocturnal hemoglobinuria in a girl with hemolysis and "hematuria".  

Science.gov (United States)

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder of unknown frequency. In its classic form, PNH is characterized by hemolysis accompanied by nocturnal hemoglobinuria. The clinical course is unpredictable and may vary from severe hemolysis and recurrent venous thrombosis to latent periods with milder symptoms. We report a 15-year-old girl with hemolytic episodes, abdominal pain, and passage of dark urine. Hemoglobinuria was demonstrated by a "blood"-positive dipstick test in the absence of red blood cells in the urinary sediment. The diagnosis of PNH was confirmed by flow cytometry. PMID:15278422

Dolezel, Zdenek; Dostalkova, Dana; Blatny, Jan; Starha, Jiri; Gerykova, Hana

2004-10-01

324

Presence of melatonin in various cat brainstem nuclei determined by radioimmunoassay  

International Nuclear Information System (INIS)

Microdissected samples of juvenile cat brain tissue were assayed for melatonin content using a double antibody radioimmunoassay. Immunoreactive melatonin was consistently detected, albeit in variable amounts, in pineal, habenula, the region of the nucleus gracilis, gigantocellular reticular formation of the pons and medulla oblongata. Among the negative areas were raphe nuclei, substantia nigra dn locus caeruleus. These findings suggest that melatonin may play a role in some structures of the central nervous system outside the pineal-hypothalamo-pituitary axis. This immunoreactive melatonin could reflect a local synthesis, or a tissular uptake of melatonin from blood or cerebrospinal fluid. (author)

325

Study Of The Effect Of Melatonin On Water Immersion Stress-Induced Gastric Lesions  

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Full Text Available One of the useful function of melatonin is its protective effect against endogenous oxidants. The object of this investigation was to study the protective effect of melatonin on stress-induced gastric lesions."nResults: Our results show that pretreatment of animals with melatonin decrease the stress-induced gastric lesions dose dependently."nL-NAME, a nitric oxide synthesis inhibitor, potentiat the stress-induce gastric lesions and melatonin produced gastro-protective effect against concurrent stress and L-NAME-induced gastric lesions."nConclusion: Our results indicate that melatonin may produce its gastro-protective effect Via increasing level of nitric oxide.

M. Samini

2003-08-01

326

Induction of sexual activity of male creole goats in subtropical northern Mexico using long days and melatonin.  

Science.gov (United States)

The aim of this study was to determine whether the sexual activity of local male Creole goats in subtropical Mexico can be induced during the non-breeding season by a long-day treatment followed by insertion of two melatonin implants. The experiment was carried out in the Laguna region in the State of Coahuila, Mexico (26 degrees N). Fourteen male goats were allocated to two balanced groups (n = 7 each) according to body and testicular weights. Males were kept together in two separate groups and fed lucerne hay for ad libitum intake and 300 g of commercial concentrate and had free access to water and mineral blocks. The control group remained in open sheds under natural photoperiod and ambient temperature conditions. The experimental group was placed in a light-proof building and exposed to 2.5 mo of long days (16 h of light/d) from November 1 to January 15. On January 16, each male received two s.c. melatonin implants and was exposed to natural photoperiodic changes in an open shed. In the control group, testicular weight exhibited seasonal variations; the highest value occurred on May 30 (146 +/- 10 g). Treated males reached maximum testicular weight earlier (March 15; 147 +/- 11 g), and sperm quality from January to March was higher than that observed in the control group (P testosterone remained low until mid-June and increased thereafter to remain elevated until the end of the study. In the experimental group, elevated plasma testosterone was observed from February to April and from July to November. Treating male goats in subtropical latitudes with artificial long days and melatonin can induce an intense sexual activity during the natural nonbreeding season. PMID:11583410

Delgadillo, J A; Carrillo, E; Morán, J; Duarte, G; Chemineau, P; Malpaux, B

2001-09-01

327

Melatonin and its potential biological functions in the fruits of sweet cherry.  

Science.gov (United States)

Melatonin is a well-known molecule which possesses many beneficial effects on human health. Many agriculture products provide natural melatonin in the diet. Cherry is one such fruit as they are rich in melatonin. In order to understand the biological roles of melatonin in cherry fruit, melatonin synthesis and its changes over 24 hr period were systematically monitored both during their development and in the ripe cherries in two cultivars, 'Hongdeng' (Prunus avium L. cv. Hongdeng) and 'Rainier' (Prunus avium L. cv. Rainier). It was found that both darkness and oxidative stress induced melatonin synthesis, which led to dual melatonin synthetic peaks during a 24 hr period. The high levels of malondialdehyde induced by high temperature and high intensity light exposure were directly related to up-regulated melatonin production. A primary function of melatonin in cherry fruits is speculated to be as an antioxidant to protect the cherry from the oxidative stress. Importantly, plant tryptophan decaboxylase gene (PaTDC) was identified in cherry fruits. Our data shows that PaTDC expression is positively related to the melatonin production in the cherry. This provides additional information to suggest that tryptophan decaboxylase is a rate-limiting enzyme of melatonin synthesis in plants. PMID:23480341

Zhao, Yu; Tan, Dun-Xian; Lei, Qiong; Chen, Hao; Wang, Lin; Li, Qing-tian; Gao, Yinan; Kong, Jin

2013-08-01

328

Adrenergic Activation of Melatonin Secretion in Ovine Pineal Explants in Short-Term Superfusion Culture Occurs via Protein Synthesis Independent and Dependent Phenomena  

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The ovine pineal is generally considered as an interesting model for the study on adrenergic regulation of melatonin secretion due to some functional similarities with this gland in the human. The present investigations, performed in the superfusion culture of pineal explants, demonstrated that the norepinephrine-induced elevation of melatonin secretion in ovine pinealocytes comprised of two subsequent periods: a rapid increase phase and a slow increase phase. The first one included the quick rise in release of N-acetylserotonin and melatonin, occurring parallel to elevation of NE concentration in the medium surrounding explants. This rapid increase phase was not affected by inhibition of translation. The second, slow increase phase began after NE level had reached the maximum concentration in the culture medium and lasted about two hours. It was completely abolished by the treatment with translation inhibitors. The obtained results showed for the first time that the regulation of N-acetylserotonin synthesis in pinealocytes of some species like the sheep involves the on/off mechanism, which is completely independent of protein synthesis and works very fast. They provided strong evidence pointing to the need of revision of the current opinion that arylalkylamines N-acetyltransferase activity in pinealocytes is controlled exclusively by changes in enzyme abundance. PMID:25133175

2014-01-01

329

Rat liver mitochondrial damage under acute or chronic carbon tetrachloride-induced intoxication: Protection by melatonin and cranberry flavonoids  

Energy Technology Data Exchange (ETDEWEB)

In current societies, the risk of toxic liver damage has markedly increased. The aim of the present work was to carry out further research into the mechanism(s) of liver mitochondrial damage induced by acute (0.8 g/kg body weight, single injection) or chronic (1.6 g/ kg body weight, 30 days, biweekly injections) carbon tetrachloride – induced intoxication and to evaluate the hepatoprotective potential of the antioxidant, melatonin, as well as succinate and cranberry flavonoids in rats. Acute intoxication resulted in considerable impairment of mitochondrial respiratory parameters in the liver. The activity of mitochondrial succinate dehydrogenase (complex II) decreased (by 25%, p < 0.05). Short-term melatonin treatment (10 mg/kg, three times) of rats did not reduce the degree of toxic mitochondrial dysfunction but decreased the enhanced NO production. After 30-day chronic intoxication, no significant change in the respiratory activity of liver mitochondria was observed, despite marked changes in the redox-balance of mitochondria. The activities of the mitochondrial enzymes, succinate dehydrogenase and glutathione peroxidase, as well as that of cytoplasmic catalase in liver cells were inhibited significantly. Mitochondria isolated from the livers of the rats chronically treated with CCl{sub 4} displayed obvious irreversible impairments. Long-term melatonin administration (10 mg/kg, 30 days, daily) to chronically intoxicated rats diminished the toxic effects of CCl{sub 4}, reducing elevated plasma activities of alanine aminotransferase and aspartate aminotransferase and bilirubin concentration, prevented accumulation of membrane lipid peroxidation products in rat liver and resulted in apparent preservation of the mitochondrial ultrastructure. The treatment of the animals by the complex of melatonin (10 mg/kg) plus succinate (50 mg/kg) plus cranberry flavonoids (7 mg/kg) was even more effective in prevention of toxic liver injury and liver mitochondria damage. Highlights: ? After 30-day chronic CCl{sub 4} intoxication mitochondria displayed considerable changes. ? The functional parameters of mitochondria were similar to the control values. ? Melatonin + succinate + flavonoids prevented mitochondrial ultrastructure damage. ? The above complex enhanced regenerative processes in the liver.

Cheshchevik, V.T. [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Department of Biochemistry, Yanka Kupala Grodno State University, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Lapshina, E.A.; Dremza, I.K.; Zabrodskaya, S.V. [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Reiter, R.J. [Department of Cellular and Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229–3900 (United States); Prokopchik, N.I. [Grodno State Medical University, Gorkogo - 80, 230015 Grodno (Belarus); Zavodnik, I.B., E-mail: zavodnik_il@mail.ru [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Department of Biochemistry, Yanka Kupala Grodno State University, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus)

2012-06-15

330

Melatonin content of pepper and tomato fruits: effects of cultivar and solar radiation.  

Science.gov (United States)

We evaluated the effect of cultivar and solar radiation on the melatonin content of Capsicum annuum (pepper) and Solanum lycopersicum (tomato) fruits. The melatonin content of red pepper fruits ranged from 31 to 93ngg(-1) (dry weight). The melatonin content of tomato ranged from 7.5 to 250ngg(-1) (dry weight). We also studied the effect of ripeness on melatonin content and identified one group of pepper cultivars in which the melatonin content increased as the fruit ripened and another in which it decreased as the fruit ripened. Under shade conditions, the melatonin content in most of tomato cultivars tended to increase (up to 135%), whereas that of most pepper cultivars decreased (to 64%). Overall, the results also demonstrated that the melatonin content of the fruits was not related to carbon fluxes from leaves. PMID:24629979

Riga, Patrick; Medina, Sonia; García-Flores, Libia Alejandra; Gil-Izquierdo, Ángel

2014-08-01

331

Contribution of the daily melatonin profile to diagnosis of tumors of the pineal region.  

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Tumors of the pineal region (TPR) include different entities: germ cell tumors (GCT), pineal parenchymal tumors (PPT), meningiomas, and glial tumors. Except for GCT, there are no peripheral markers and histopathological diagnosis needs biopsy or surgery. We studied daily melatonin variations in twenty-nine patients with TPR and five with tectal plate glioma (TPG), used as controls, before and/or after surgery. Before surgery, a melatonin nycthemeral rhythm was observed in patients with TPG and TPR (one cyst, three PPT, one papillary tumor of the pineal region, two meningiomas, six gliomas). Melatonin rhythm was dramatically reduced for undifferentiated or invasive tumors. After surgery, the absence of melatonin variation in some cases could be the consequence of pineal damage by surgery. The contribution of determination of melatonin profiles to the diagnosis of TPR remains limited but of interest. The evidence for melatonin deficiency could justify melatonin administration to prevent the postpinealectomy syndrome. PMID:19169855

Leston, José; Mottolese, Carmine; Champier, Jacques; Jouvet, Anne; Brun, Jocelyne; Sindou, Marc; Chazot, Guy; Claustrat, Bruno; Fèvre-Montange, Michelle

2009-07-01

332

Formation of melatonin and its isomer during bread dough fermentation and effect of baking.  

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Melatonin is produced mainly by the pineal gland in vertebrates. Also, melatonin and its isomer are found in foods. Investigating the formation of melatonin and its isomer is of importance during bread dough fermentation and its degradation during baking since bread is widely consumed in high amounts. Formation of melatonin was not significant during dough fermentation. The melatonin isomer content of nonfermented dough was found to be 4.02 ng/g and increased up to 16.71 ng/g during fermentation. Lower amounts of isomer in crumb and crust than dough showed that the thermal process caused a remarkable degree of degradation in melatonin isomer. At the end of the 180 min fermentation Trp decreased by 58%. The results revealed for the first time the formation of a melatonin isomer in bread dough during yeast fermentation. PMID:24611648

Y?lmaz, Cemile; Kocada?l?, Tolgahan; Gökmen, Vural

2014-04-01

333

Synthesis of 2-iodo- and 2-phenyl-[{sup 11}C]melatonin: potential PET tracers for melatonin binding sites  

Energy Technology Data Exchange (ETDEWEB)

Two {sup 11}C-labelled melatonin derivatives, 2-iodo-[{sup 11}C]melatonin (2-iodo-5-methoxy-N[{sup 11}C-acetyl]-tryptamine, an agonist) and 2-phenyl-[{sup 11}C]melatonin (2-phenyl-5-methoxy-N[{sup 11}C-acetyl]tryptamine, a putative antagonist) were synthesized from [{sup 11}C]carbon dioxide. The reaction sequence was common to both compounds and consisted of three steps: (i) carbonylation of methyl magnesium bromide with [{sup 11}C]carbon dioxide, (ii) conversion of the adduct to [{sup 11}C]acetyl chloride, (iii) acetylation of the amine precursors (2-iodo-5-methoxy-tryptamine or 2-phenyl-5-methoxy-tryptamine) with [{sup 11}C]acetyl chloride. The precursors were especially prepared. The radiochemical yield was 19% for 2-iodomelatonin and 32% for 2-phenymelatonin, based on [{sup 11}C]carbon dioxide; the specific activity ranged from 300 to 600 mCi/{mu}mol. Both labelled 2-substituted-melatonins are intended to be used as radiotracers to study melatonin binding sites in man with positron emission tomography.

Chen Jiajun; Fiehn-Schulze, Brita; Firnau, Guenter [Section of Radiology and Nuclear Medicine, Hamilton Health Sciences Corporation, McMaster University Medical Centre, Hamilton, ON (Canada); Brough, Paul A.; Snieckus, Victor [Department of Chemistry, University of Waterloo, Waterloo, ON (Canada)

1998-12-01

334

Theoretical insight into the antioxidant properties of melatonin and derivatives.  

Science.gov (United States)

Density functional theory calculations on melatonin, metabolites and synthetic derivatives thereof, and a range of other biological antioxidant molecules are presented, with a view to understanding the antioxidant ability of these molecules. After testing of the necessary calculations, we show that melatonin lies close to vitamin E on a donor-acceptor map, indicating that it should be an excellent electron donor but a poor acceptor. The neutral radical metabolite of melatonin is predicted to be an even better donor, whereas other metabolites and synthetic derivatives should retain antioxidant ability but are less powerful than the parent. QSAR models of antioxidant activity, measured in two different assays, are presented. We show that octanol-water partition coefficient is an excellent predictor of activity in lipophilic media, while properties related to electron donor/acceptor power give good fits against activity in aqueous media. PMID:25164170

Johns, Jeffrey R; Platts, James A

2014-10-21

335

Concentration-dependent effect of melatonin on DSPC membrane  

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The concentration-induced effects of melatonin on distearoyl phosphatidylcholine (DSPC) model membranes were investigated by using two different non-invasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). An investigation of the Csbnd H, Cdbnd O and PO2- double bond stretching mode in FTIR spectra and DSC studies reveals that the inclusion of melatonin changes the physical properties of the DSPC multilamellar liposomes (MLVs) by shifting the main phase transition to lower temperatures, abolishing the pretransition, ordering the system in the gel phase and slightly disordering the system in the liquid crystalline phase, increasing the dynamics both in the gel phase and liquid crystalline phases. Melatonin also causes strong hydrogen bonding between Cdbnd O and PO2- groups of lipids and the water molecules around.

Sahin, Ipek; Bilge, Duygu; Kazanci, Nadide; Severcan, Feride

2013-11-01

336

Identification and characteristic of melatonin receptor in human stomach  

International Nuclear Information System (INIS)

To determine whether melatonin receptors (MR) exist in human stomach, specific binding of melatonin receptor i human stomach was measured by radioligand binding assay. The maximum binding capacity (Bmax) of MR was 0.48 +- 0.11 fmol/mg protein. Equilibrium dissociation constant (Kd) of MR was 51 +- 17 pmol/L. Standard criteria of binding sites-saturability, reversibility, specificity and high affinity were observed in this assay to determine melatonin binding sites. The following was the subcellular distribution of MR in human stomach in an descending order: nuclear, mitochondrial, microsomal and cytosol. Specific binding of MR could be inhibited by GTPrS. Conclusion: MRs are present in the human stomach and the above findings suggested that MR may be coupled with Gi protein system

337

The pineal neurohormone melatonin and its physiologic opiatergic immunoregulatory role  

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Full Text Available The pineal gland functions as a neuroendocrine transducer that coordinate the organism response to changing environmental stimuli such as light and temperature. The main and best known pineal neurohormone is melatonin that is synthesized and released in a circadian fashion with a peak during the night darkness hours. We have recently reported that melatonin exerts important immuno regulatory functions. Here we describe the astonishing property of exogenous melatonin which is able to counteract completely the depressive effect of anxiety-restraint stress and/or of corticosterone on thymus weight, andibody production and antiviral responses. This effect seems to be mediated by antigen-activated T cells via an opiatergic mechanism.

Georges J. M. Maestroni

1987-01-01

338

The pineal neurohormone melatonin and its physiologic opiatergic immunoregulatory role  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The pineal gland functions as a neuroendocrine transducer that coordinate the organism response to changing environmental stimuli such as light and temperature. The main and best known pineal neurohormone is melatonin that is synthesized and released in a circadian fashion with a peak during the nig [...] ht darkness hours. We have recently reported that melatonin exerts important immuno regulatory functions. Here we describe the astonishing property of exogenous melatonin which is able to counteract completely the depressive effect of anxiety-restraint stress and/or of corticosterone on thymus weight, andibody production and antiviral responses. This effect seems to be mediated by antigen-activated T cells via an opiatergic mechanism.

Georges J. M., Maestroni; Ario, Conti; Walter, Pierpaoli.

339

Melatonin acts as antioxidant and improves sleep in MS patients.  

Science.gov (United States)

The relationship between the prevalence of multiple sclerosis (MS) and sunlight's ultraviolet radiation was proved. Oxidative stress plays a role in the pathogenic traits of MS. Melatonin possesses antioxidative properties and regulates circadian rhythms. Sleep disturbances in MS patients are common and contribute to daytime fatigue. The aim of study was to evaluate 5 mg daily melatonin supplementation over 90 days on serum total oxidant status (TOS), total antioxidant capacity (TAC) and its influence on sleep quality and depression level of MS patients. A case-control prospective study was performed on 102 MS patients and 20 controls matched for age and sex. The Kurtzke's Expanded Disability Status Scale, magnetic resonance imaging examinations, Athens Insomnia Scale (AIS), Beck Depression Inventory questionnaires were completed. Serum TOS and TAC levels were measured. We observed higher serum levels of TOS in all MS groups, while after melatonin treatment the TOS levels significantly decreased. The TAC level was significantly lower only in mitoxantrone-treated group and it increased after melatonin supplementation. A strong positive correlation between T1Gd(+) number lesions and TAC level in interferon-beta-1A group was observed. AIS group mean score above 6 defining insomnia were observed in interferon-beta-1B-group, glatiramer acetate-group and mitoxantrone-group: 6.62 ± 2.88, 8.45 ± 2.07, 11.1 ± 3.25, respectively. After melatonin treatment the AIS mean scores decrease in glatiramer acetate-group and mitoxantrone-group achieving 5.25 ± 1.14 and 7.08 ± 2.39, respectively (p < 0.05). Finding from our study suggest that melatonin can act as an antioxidant and improves reduced sleep quality in MS patients. PMID:24974099

Adamczyk-Sowa, Monika; Pierzchala, Krystyna; Sowa, Pawel; Mucha, Sebastian; Sadowska-Bartosz, Izabela; Adamczyk, Jowita; Hartel, Marcin

2014-08-01

340

Sleep efficiency and nocturnal hemodynamic dipping in young, normotensive adults.  

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Blunted dipping of nocturnal systolic arterial pressure (SAP) and heart rate (HR) are independent risk factors for hypertension and all-cause mortality. While several epidemiological studies report a significant association between short sleep duration and hypertension, associations between sleep efficiency and the nocturnal drop of SAP remain controversial. Moreover, relations between sleep efficiency and HR diurnal patterns have been overlooked. We hypothesized that low sleep efficiency (normotensive subjects (13 men, 9 women; age: 18-28 yr) wore an actigraphy watch for 7 days and nights, and an ambulatory blood pressure monitor for 24 h on a nonactigraph night. There were no differences in age, sex, body mass index, mean sleep time, number of awakenings, or 24-h blood pressure between the low (n = 12) and high (n = 10) sleep efficiency groups. However, the low sleep efficiency subjects demonstrated a blunted dip of nocturnal SAP (10 ± 1% vs. 14 ± 1%, P = 0.04) and HR (12 ± 3% vs. 21 ± 3%, P = 0.03) compared with the high sleep efficiency group. The low sleep efficiency group also demonstrated a higher mean nocturnal HR (63 ± 2 vs. 55 ± 2 beats/min; P = 0.02). These findings support growing evidence that sleep efficiency, independent of total sleep time, may be an important cardiovascular risk factor. PMID:25031228

Ross, Amanda J; Yang, Huan; Larson, Robert A; Carter, Jason R

2014-10-01

 
 
 
 
341

Wild Chimpanzees on the Edge: Nocturnal Activities in Croplands  

Science.gov (United States)

In a rapidly changing landscape highly impacted by anthropogenic activities, the great apes are facing new challenges to coexist with humans. For chimpanzee communities inhabiting encroached territories, not bordered by rival conspecifics but by human agricultural fields, such boundaries are risky areas. To investigate the hypothesis that they use specific strategies for incursions out of the forest into maize fields to prevent the risk of detection by humans guarding their field, we carried out video recordings of chimpanzees at the edge of the forest bordered by a maize plantation in Kibale National Park, Uganda. Contrary to our expectations, large parties are engaged in crop-raids, including vulnerable individuals such as females with clinging infants. More surprisingly chimpanzees were crop-raiding during the night. They also stayed longer in the maize field and presented few signs of vigilance and anxiety during these nocturnal crop-raids. While nocturnal activities of chimpanzees have been reported during full moon periods, this is the first record of frequent and repeated nocturnal activities after twilight, in darkness. Habitat destruction may have promoted behavioural adjustments such as nocturnal exploitation of open croplands. PMID:25338066

Krief, Sabrina; Cibot, Marie; Bortolamiol, Sarah; Seguya, Andrew; Krief, Jean-Michel; Masi, Shelly

2014-01-01

342

Orthodontic maxillary expansion and its effect on nocturnal enuresis.  

Science.gov (United States)

A previous retrospective study of 10 children with varying degrees of nocturnal enuresis has shown that one side effect of rapid maxillary expansion (RME) is spontaneous reduction in bed-wetting at night. The aim of this prospective study was to analyze the effect of RME treatment (mean 2 weeks) in cases of chronic, long-standing nocturnal enuresis. Ten children, 8 to 13 years old, who had not responded to conventional medical treatment for bed-wetting, were referred from the pediatric department. Within 1 month of RME of 3 to 5 mm, 4 children were completely dry and 3 showed notable improvement. The results are encouraging, especially given the spontaneous recovery rate of about 15% per year. A reduction in nocturnal enuresis in children has also been reported after tonsillectomy. However, in this pilot study, no significant associations could be found between improvement in nocturnal enuresis and improvement in the nasal airway, age, amount of expansion, or nasopharyngeal dimension (measured on cephalograms). PMID:9622759

Kurol, J; Modin, H; Bjerkhoel, A

1998-06-01

343

Targeting nocturnal hypertension in type 2 diabetes mellitus.  

Science.gov (United States)

Several studies in different populations have suggested that nighttime blood pressure (BP) is a stronger predictor of cardiovascular events than daytime BP. Consequently, treatment strategies to target nighttime BP have come into focus. The aim of the present study was to investigate the effect of change of administration time of antihypertensive drugs. We included 41 patients with type 2 diabetes mellitus and nocturnal hypertension (nighttime systolic BP >120 mm Hg) in an open-label, crossover study. Patients were randomized to 8 weeks of either morning or bedtime administration of all of the individual's once-daily antihypertensive drugs, followed by 8 weeks of switched dosing regimen. Bedtime administration of antihypertensive drugs resulted in a significant reduction in nighttime (7.5 mm Hg; PC-reactive protein were significantly lower with bedtime administration, which may indicate an effect on low-grade inflammation. We found no difference in urinary albumin excretion, regardless of albuminuria status. Urinary sodium/creatinine was significantly increased and urinary osmolality significantly reduced with bedtime administration, which can be interpreted as increased nocturnal natriuresis. In patients with type 2 diabetes mellitus and nocturnal hypertension, administration of once-daily antihypertensive drugs at bedtime may be favorable. The increased nocturnal natriuresis may reflect increased effect of bedtime-administered thiazides and renin-angiotensin system inhibitors, suggesting a potential mechanism of the observed effects on BP with chronotherapeutic intervention. PMID:25259747

Rossen, Niklas Blach; Knudsen, Søren Tang; Fleischer, Jesper; Hvas, Anne-Mette; Ebbehøj, Eva; Poulsen, Per Løgstrup; Hansen, Klavs Würgler

2014-11-01

344

The impact of nocturnal hemodialysis on sexual function  

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Full Text Available Abstract Background Sexual dysfunction is common in patients with end stage renal disease (ESRD and treatment options are limited. Observational studies suggest that nocturnal hemodialysis may improve sexual function. We compared sexual activity and responses to sexual related questions in the Kidney Disease Quality of Life Short Form questionnaire among patients randomized to frequent nocturnal or thrice weekly conventional hemodialysis. Methods We performed a secondary analysis of data from an RCT which enrolled 51 patients comparing frequent nocturnal and conventional thrice weekly hemodialysis. Sexual activity and responses to sexual related questions were assessed at baseline and six months using relevant questions from the Kidney Disease Quality of Life Short Form questionnaire. Results Overall, there was no difference in sexual activity, or the extent to which people were bothered by the impact of kidney disease on their sex life between the two groups between randomization and 6?months. However, women and patients age? Conclusions Our results suggest that frequent nocturnal hemodialysis is not associated with an improvement in sexual activity in all patients but might have an effect on the burden of kidney disease on sex life in women and patients less than 60?years of age. The validity of these subgroup findings require confirmation in future RCTs.

Bass Adam

2012-07-01

345

Renal and hepatic scintigraphy in paroxysmal nocturnal hemoglobinuria (PNH)  

International Nuclear Information System (INIS)

Scintigraphic findings in paroxysmal nocturnal hemoglobinuria (PNH) have been presented. To summarize, a focal hot spot on liver imaging was better seen on the IDA scan, showing resolution following a satisfactory portacaval anastomosis. PNH is another cause of hot kidneys on bone imaging

346

Melatonin Serum Levels in Rheumatoid Arthritis  

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Full Text Available Objective: Recent studies suggest that endogenous melatonin (MLT production might play a role in the etiology of rheumatoid arthritis (RA. However, the role of MLT in RA pathogenesis remains unclear. This study was performed to determine MLT serum levels in RA patients.Materials and Methods: Twenty nine patients with RA and in 25 age- and sex-matched healthy controls were included in our study. Blood samples of the participants collected at 8AM. MLT was measured by enzyme-linked immunosorbent assay (ELISA. The MLT levels of the patients with RA were compared with healthy age- and sex-matched controls. The Mann-Whitney U-test was used to compare the data between the two groups.Results: MLT concentrations were significantly higher in RA patients than in the controls (p<0.05.Conclusion: Our results suggest that the higher blood concentrations of MLT in RA patients, especially in the early morning, may help to explain the morning stiffness and joint swelling. Turk J Phys Med Rehab 2013;59:42-4.

Tuba BAYKAL

2013-03-01

347

Hemoglobinuria paroxística nocturna: Actualización / Paroxysmal nocturnal haemoglobinuria  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish La hemoglobinuria paroxística nocturna (HPN) es una enfermedad clonal y adquirida causada por una mutación somática en el gen PIG-A que se encuentra en el cromosoma X y codifica una proteina involucrada en la síntesis del glicosilfosfatidilinositol (GPI), el cual le sirve como anclaje a muchas prote [...] ínas de la membrana celular. La mutación ocurre en el stem cell hematopoyético y da lugar a una deficiencia parcial o total de la proteína PIG-A con la consecuente alteración en la síntesis del GPI de anclaje; como resultado, una parte de las células sanguíneas serán deficientes de todas las proteínas ligadas al GPI. La ausencia de estas proteinas en la HPN explica algunos de los síntomas clínicos de la enfermedad, como la hemólisis intravascular mediada por el complemento, la trombosis venosa, el déficit de la hematopoyesis, etc; pero no el mecanismo mediante el cual el clon HPN se expande en la médula ósea. Varios estudios han demostrado que la inactivación del gen PIG- A por sí sola, no confiere una ventaja proliferativa al stem cell mutado, uno o más factores ambientales externos son necesarios para la expansión de este clon mutado, los cuales ejercen una presión selectiva a favor del clon HPN. La causa por el cual el clon HPN se estimula a proliferar podría ser un daño selectivo a la hematopoyesis normal. En el tratamiento de esta enfermedad se han utilizado varios agentes terapéuticos, pero el único tratamiento curativo es el trasplante de progenitores hematopoyéticos Abstract in english The paroxysmal nocturnal haemoglobinuria (PNH) is a clonal acquired disease caused by a somatic mutation in the PIG-A gene that is located in the chromosome X and codifies a protein involved in the synthesis of glycosil phosphatidylinositol (GPI), which serves as an anchor for many proetins of the c [...] ellular membrane. The mutations occurs in the hematopoietic stem cell and gives rise to a partial or total deficiency of the protein PIG-A with the subsequent alteration in the synthesis of the anchored GPI. As a result, a part of the blood cells will be lacking all the proteins bound to the GPI. The absence of these proteins in the NPH explains some of the clinical symptoms of the disease, such as the intravascular hemolysis mediated by the complement, the venous thrombosis, the deficit of hematopoiesis, etc., but not the mechanism by which the NPH clone expands into the bone marrow. Some studies have proved that the inactivation of the GPI-A gene does not confer a proliferative advantage to the mutated stem cell. One or more external environmental factors are needed for the expansion of this mutated clone. These factors exert a selective pressure in favor of the NPH clone. The cause for which the NPH clone is estimulated to proliferate may be a selective damage to the normal hematopoiesis. Several therapeutic agents have been used in the treatment of this disease, but the only curative treatment is the transplantation of hematopoietic progenitors

María Teresa, Milanés Roldán; Norma, Fernández Delgado; Teresa, Fundora Sarraff; Juan Carlos, Jaime Facundo; Porfirio, Hernández Ramírez.

2003-04-01

348

The inhibition of apoptosis by melatonin in VSC4.1 motoneurons exposed to oxidative stress, glutamate excitotoxicity, or TNF-alpha toxicity involves membrane melatonin receptors.  

Science.gov (United States)

Loss of motoneurons may underlie some of the deficits in motor function associated with the central nervous system (CNS) injuries and diseases. We tested whether melatonin, a potent antioxidant and free radical scavenger, would prevent motoneuron apoptosis following exposure to toxins and whether this neuroprotection is mediated by melatonin receptors. Exposure of VSC4.1 motoneurons to either 50 microm H(2)O(2), 25 microm glutamate (LGA), or 50 ng/mL tumor necrosis factor-alpha (TNF-alpha) for 24 h caused significant increases in apoptosis, as determined by Wright staining and ApopTag assay. Analyses of mRNA and proteins showed increased expression and activities of stress kinases and cysteine proteases and loss of mitochondrial membrane potential during apoptosis. These insults also caused increases in intracellular free [Ca(2+)] and activities of calpain and caspases. Cells exposed to stress stimuli for 15 min were then treated with 200 nm melatonin. Post-treatment of cells with melatonin attenuated production of reactive oxygen species (ROS) and phosphorylation of p38, MAPK, and JNK1, prevented cell death, and maintained whole-cell membrane potential, indicating functional neuroprotection. Melatonin receptors (MT1 and MT2) were upregulated following treatment with melatonin. To confirm the involvement of MT1 and MT2 in providing neuroprotection, cells were post-treated (20 min) with 10 microm luzindole (melatonin receptor antagonist). Luzindole significantly attenuated melatonin-induced neuroprotection, suggesting that melatonin worked, at least in part, via its receptors to prevent VSC4.1 motoneuron apoptosis. Results suggest that neuroprotection rendered by melatonin to motoneurons is receptor mediated and melatonin may be an effective neuroprotective agent to attenuate motoneuron death in CNS injuries and diseases. PMID:20082663

Das, Arabinda; McDowell, Misty; Pava, Matthew J; Smith, Joshua A; Reiter, Russel J; Woodward, John J; Varma, Abhay K; Ray, Swapan K; Banik, Naren L

2010-03-01

349

Distribution, function and physiological role of melatonin in the lower gut  

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Full Text Available Melatonin is a hormone with endocrine, paracrine and autocrine actions. It is involved in the regulation of multiple functions, including the control of the gastrointestinal (GI system under physiological and pathophysiological conditions. Since the gut contains at least 400 times more melatonin than the pineal gland, a review of the functional importance of melatonin in the gut seems useful, especially in the context of recent clinical trials. Melatonin exerts its physiological effects through specific membrane receptors, named melatonin-1 receptor (MT1, MT2 and MT3. These receptors can be found in the gut and their involvement in the regulation of GI motility, inflammation and pain has been reported in numerous basic and clinical studies. Stable levels of melatonin in the lower gut that are unchanged following a pinealectomy suggest local synthesis and, furthermore, implicate physiological importance of endogenous melatonin in the GI tract. Presently, only a small number of human studies report possible beneficial and also possible harmful effects of melatonin in case reports and clinical trials. These human studies include patients with lower GI diseases, especially patients with irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. In this review, we summarize the presently available information on melatonin effects in the lower gut and discuss available in vitro and in vivo data. We furthermore aim to evaluate whether melatonin may be useful in future treatment of symptoms or diseases involving the lower gut.

Chun-Qiu Chen

2011-01-01

350

Melatonin binding sites are functionally coupled to phosphoinositide hydrolysis in Syrian hamster RPMI 1846 melanoma cells.  

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Recent pharmacological studies demonstrate that Syrian hamster melanoma (RPMI 1846) cells possess a nanomolar-affinity binding site for melatonin. Inhibition of 2-[125I]-iodomelatonin binding to RPMI membranes by melatonergic ligands exhibit a rank order relationship similar to that observed in hamster hypothalamus. Biochemical studies indicate that the melatonin binding site in RPMI 1846 cells is not coupled in either a stimulatory or inhibitory fashion to adenylate cyclase as a second messenger. We now report that stimulation of RPMI 1846 melanoma cells with melatonergic agonists induces phosphoinositide hydrolysis in a concentration-dependent manner (EC50: N-acetylserotonin = 0.29 microM; 2-I-Melatonin = 0.39 microM; 6-Cl-Melatonin = 0.38 microM; Melatonin = 0.45 microM). Further, phosphoinositide hydrolysis induced by 2-I-melatonin and N-acetylserotonin was blocked by pre-incubation with the melatonin antagonist N-acetyltryptamine and prazosin, an antagonist which exhibits potency at the nanomolar affinity melatonin binding site. 2-I-melatonin and N-acetylserotonin-induced phosphoinositide hydrolysis were not blocked by the serotonin type 2 antagonist ketanserin or alpha-adrenergic antagonist, phentolamine. These data suggest that melatonin binding sites on RPMI 1846 cells are linked to phosphoinositide hydrolysis as a second messenger. PMID:8246675

Eison, A S; Mullins, U L

1993-01-01

351

Beneficial effects of melatonin on bovine oocytes maturation: a mechanistic approach.  

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This study was performed to investigate the effect of melatonin on bovine oocyte maturation and subsequent embryonic development in vitro. The endogenous melatonin concentration in bovine follicular fluid is approximately 10(-11) M. To examine the potential beneficial effects of melatonin on bovine oocyte maturation in vitro, germinal vesicle (GV) oocytes were incubated with different concentrations of melatonin (10(-11), 10(-9), 10(-7), 10(-5), 10(-3) M). Melatonin supplementation at suitable concentrations significantly promoted oocyte maturation. The development of embryos and the mean cell number/blastocyst produced after in vitro fertilization were remarkably improved. The most effective melatonin concentrations obtained from the studies ranged from 10(-9) to 10(-7) M. The expression of melatonin receptor MT1 and MT2 genes was identified in cumulus cells, granulosa cells, and oocytes using reverse transcription PCR, immunofluorescence, and Western blot. The mechanistic studies show that the beneficial effects of melatonin on bovine oocyte maturation are mediated via melatonin membrane receptors as the melatonin receptor agonist (IIK7) promotes this effect while the melatonin receptor antagonist (luzindole) blocks this action. Mechanistic explorations revealed that melatonin supplementation during bovine oocyte maturation significantly up-regulated the expressions of oocyte maturation-associated genes (GDF9, MARF1, and DNMT1a) and cumulus cells expansion-related gene (PTX3, HAS1/2) and that LHR1/2, EGFR are involved in signal transduction and epigenetic reprogramming. The results obtained from the studies provide new information regarding the mechanisms by which melatonin promotes bovine oocyte maturation in vitro and provide an important reference for in vitro embryo production of bovine and the human-assisted reproductive technology. PMID:25070516

Tian, XiuZhi; Wang, Feng; He, ChangJiu; Zhang, Lu; Tan, DunXian; Reiter, Russel J; Xu, Jing; Ji, PengYun; Liu, GuoShi

2014-10-01

352

The effect of elevation data representation on nocturnal drainage wind simulations. Revision 1  

Energy Technology Data Exchange (ETDEWEB)

A critical requirement for accurately representing surface-atmosphere interactions within an atmospheric model is to realistically characterize the land surface. Data must be extracted from a geographical database and transformed so that it is consistent with the needs of the numerical model. In such a process, there are two major classes of error that must be understood and minimized whenever possible. The first class involves the accuracy, precision, and resolution of the geographical data itself. The second is error introduced by the transformations used to assimilate the data into the atmospheric model. Thus, this research has two coupled objectives: to understand the effects of errors within the geographical data base upon the accuracy of the atmospheric model simulation and to design optimal techniques for the transformation of the data.

Walker, H.; Leone, J.M. Jr.

1994-02-04

353

A novel and sensitive radioreceptor assay for serum melatonin levels  

International Nuclear Information System (INIS)

A simple and sensitive radioreceptor assay (RRA) has been developed to measure melatonin levels in serum. The assay is based on competition between 2-[125I]iodomelatonin ([125I]MEL) and melatonin for binding to high-affinity binding sites in chick forebrain. To measure the amount of melatonin present in a serum sample, it was extracted with dichloromethane and added to the assay medium. The percentage inhibition of radioligand binding in the presence of the extracted serum was determined and compared to the percent displacement by known amounts of melatonin in a standard curve. There was little or no cross-reactivity with other structurally related compounds. The sensitivity of the assay is ?1.5pg/0.15 mL and the intra- and inter-assay variations are approximately 8%. Since the RRA results are comparable to that of an established radioimmunoassay (RIA), it provides a sensitive and rapid alternative to the more time consuming RIA

354

Heteromeric MT1/MT2 Melatonin Receptors Modulate Photoreceptor Function  

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The formation of G protein-coupled receptor (GPCR) heteromers elicits signaling diversification and holds great promise for improved drug selectivity. Most studies have been conducted in heterologous expression systems; however, in vivo validation is missing from most cases thus questioning the physiological significance of GPCR heteromerization. Melatonin MT1 and MT2 receptors have been shown to exist as homo- and heteromers in vitro. We show here that the effect of melatonin on rod photoreceptor light sensitivity is mediated by melatonin MT1/MT2 receptor heteromers. This effect involves activation of the heteromer-specific PLC/PKC pathway and is abolished in MT1?/? and MT2?/? mice as well as in mice overexpressing a non-functional MT2 receptor mutant that competes with the formation of functional MT1/MT2 heteromers in photoreceptor cells. This study establishes the essential role of melatonin receptor heteromers in retinal function and supports the physiological importance of GPCR heteromerization. Finally, our work may have important therapeutic implications, as the heteromer complex may provide a unique pharmacological target to improve photoreceptor functioning and to extend the viability of photoreceptors during aging. PMID:24106342

Baba, Kenkichi; Benleulmi-Chaachoua, Abla; Journe, Anne-Sophie; Kamal, Maud; Guillaume, Jean-Luc; Dussaud, Sebastien; Gbahou, Florence; Yettou, Katia; Liu, Cuimei; Contreras-Alcantara, Susana; Jockers, Ralf; Tosini, Gianluca

2013-01-01

355

Myocardial ischemia-reperfusion injury: Possible role of melatonin  

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Our knowledge and understanding of the pathophysiology of coronary atherosclerosis has increased enormously over the last 20 years. Reperfusion through thrombolysis or percutaneous coronary angioplasty is the standard treatment for p