Melatonin replacement therapy of elderly insomniacs

Investigation of the structural changes in the hippocampus and prefrontal cortex using FTIR spectroscopy in sleep deprived mice

Sleep is a basic, physiological requirement for living things to survive and is a process that covers one third of our lives. Melatonin is a hormone that plays an important role in the regulation of sleep. Sleep deprivation affect brain structures and functions. Sleep deprivation causes a decrease in brain activity, with particularly negative effects on the hippocampus and prefrontal cortex. Despite the essential role of protein and lipids vibrations, polysaccharides, fatty acid side chains functional groups, and ratios between amides in brain structures and functions, the brain chemical profile exposed to gentle handling sleep deprivation model versus Melatonin exposure remains unexplored. Therefore, the present study, aims to investigate a molecular profile of these regions using FTIR spectroscopy measurement's analysis based on lipidomic approach with chemometrics and multivariate analysis to evaluate changes in lipid composition in the hippocampus, prefrontal regions of the brain. In this study, C57BL/6J mice were randomly assigned to either the control or sleep deprivation group, resulting in four experimental groups: Control (C) (n = 6), Control + Melatonin (C + M) (n = 6), Sleep Deprivation (S) (n = 6), and Sleep Deprivation + Melatonin (S + M) (n = 6). Interventions were administered each morning via intraperitoneal injections of melatonin (10 mg/kg) or vehicle solution (%1 ethanol + saline), while the S and S + M groups underwent 6 h of daily sleep deprivation from using the Gentle Handling method. All mice were individually housed in cages with ad libitum access to food and water within a 12-hour light-dark cycle. Results presented that the brain regions affected by insomnia. The structure of phospholipids, changed. Yet, not only changes in lipids but also in amides were noticed in hippocampus and prefrontal cortex tissues. Additionally, FTIR results showed that melatonin affected the lipids as well as the amides fraction in cortex and hippocampus collected from both control and sleep deprivation groups.

Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis

Previous studies have reported inconsistent results about exogenous melatonin's sleep-promoting effects. A possible explanation relies on the heterogeneity in administration schedule and dose, which might be accountable for differences in treatment efficacy. In this paper, we undertook a systematic review and meta-analysis of double-blind, randomized controlled trials performed on patients with insomnia and healthy volunteers, evaluating the effect of melatonin administration on sleep-related parameters. The standardized mean difference between treatment and placebo groups in terms of sleep onset latency and total sleep time were used as outcomes. Dose-response and meta-regression models were estimated to explore how time of administration, dose, and other treatment-related parameters might affect exogenous melatonin's efficacy. We included 26 randomized controlled trials published between 1987 and 2020, for a total of 1689 observations. Dose-response meta-analysis showed that melatonin gradually reduces sleep onset latency and increases total sleep time, peaking at 4 mg/day. Meta-regression models showed that insomnia status (β = 0.50, p < 0.001) and time between treatment administration and the sleep episode (β = -0.16, p = 0.023) were significant predictors of sleep onset latency, while the time of day (β = -0.086, p < 0.01) was the only significant predictor of total sleep time. Our results suggest that advancing the timing of administration (3 h before the desired bedtime) and increasing the administered dose (4 mg/day), as compared to the exogenous melatonin schedule most used in clinical practice (2 mg 30 min before the desired bedtime), might optimize the efficacy of exogenous melatonin in promoting sleep.

A scoping review of over-the-counter products for depression, anxiety and insomnia in older people

BACKGROUND

Depression, anxiety, and insomnia are prevalent in older people and are associated with increased risk of mortality, dependency, falls and reduced quality of life. Prior to or whilst seeking treatment, older people often manage these symptoms or conditions using products purchased over the counter (OTC), such as medication or herbal products. This review aims to map the evidence available for OTC medications, herbal medicines and dietary supplements for depression, anxiety and insomnia in older adults.

METHODOLOGY

We carried out a scoping review, including searches of five databases to identify relevant randomised controlled trials (inception-Dec 2022). We took an inclusive approach to products to represent the wide range that may be available online. Trials were summarised according to condition and product.

RESULTS

We included 47 trials and 10 ongoing trial protocols. Most targeted insomnia (n = 25), followed by depression (n = 20), and mixed conditions (n = 2). None evaluated products targeted at anxiety alone. Where reported, most products appeared to be safe for use, but studies rarely included people with multiple comorbidities or taking concomitant medication. Some types of melatonin for insomnia (n = 19) and omega-3 fatty acids for depression (n = 7) had more substantive evidence compared to the other products.

CONCLUSION

There is a substantial gap in evidence for OTC products for anxiety in older people. This should be addressed in future trials. Research should also focus on products that are widely used, and these need to be tested in older populations that are similar to those who would use them in practice.

My voyage in the enchanted world of sleep

In this paper, I describe my 45-year career in sleep research. I started my undergraduate studies at Tel Aviv University, where I was first introduced to the enchanted world of sleep, continued to my graduate studies with Wilse B. Webb at the University of Florida, and then to post-doctoral training with Dan Kripke at the University of California at San Diego. Then, I describe the evolution of my academic career at the Technion-Israel Institute of Technology, where I started in 1975 as an Assistant Professor and retired in 2019 as the President of the Institute. I describe the areas of research that I pursued and how the research developed, emphasizing unexpected results that guided me and my lab team in new directions. This includes my early studies on ultradian rhythms, inspired by Nathaniel Kleitman's Basic Rest Activity Cyle hypothesis, utilizing the ultrashort sleep-wake paradigm to chart the 24-hour sleep propensity function, and how these studies led us to explore the role of melatonin in sleep regulation. I also explain why we directed our attention to sleep apnea, and how clinical observations led to the provocative hypothesis that sleep apnea-typically seen as a disorder-may also play a protective role. Under the leadership of my research partner and wife, Lena, we confirmed this hypothesis. Also in this article, I describe my enthusiasm for the history of our field and, as derived from my experience as a Dean of Medicine and President of a university, I share my philosophy about the role of members of academia in society. I emphasize that none of my achievements could have been accomplished without the hard work and motivation of my students and research partners, who shared my enthusiasm and passion for the enchanted world of sleep. This paper is part of the Living Legends in Sleep Research series, which is sponsored by Idorsia Pharmaceuticals and Jazz Pharmaceuticals.

The use of prolonged-release melatonin in circadian medicine: a systematic review

INTRODUCTION

Melatonin, a hormone produced by the pineal gland, regulates the sleep-wake cycle and is effective in restoring biological rhythms. Prolonged-release melatonin (PRM) is designed to mimic the natural physiological pattern of melatonin release. In circadian medicine, PRM can be used to treat sleep and circadian rhythm disorders, as well as numerous organic diseases associated with sleep disorders.

EVIDENCE ACQUISITION

This systematic review analyzed 62 studies and adhered to the PRISMA guidelines, examining the effectiveness of PRM in organic pathologies and mental disorders.

EVIDENCE SYNTHESIS

The main evidence concerns primary insomnia in subjects over the age of 55, showing significant improvements in sleep quality. In neurodevelopmental disorders, there is evidence of a positive impact on sleep quality and quality of life for patients and their caregivers. PRM shows efficacy in the treatment of sleep disorders in mood disorders, schizophrenia, and neurocognitive disorders, but requires further confirmation. The additional use of PRM is supported for the withdrawal of chronic benzodiazepine therapies. The tolerability and safety of PRM are excellent, with ample evidence supporting the absence of tolerance and dependence.

CONCLUSIONS

Overall, PRM in circadian medicine is an effective chronopharmaceutical for restoring the sleep-wake rhythm in patients with insomnia disorder. This efficacy may also extend to sleep disorders associated with mood, neurodevelopmental and neurocognitive disorders, suggesting a further potential role in insomnia associated with various organic diseases.

Melatonin and melatonin receptor agonists in the treatment of nocturia: A systematic review

AIM

Causes of nocturia may extend beyond primary bladder pathology and it has been commonly associated as a side effect of sleep disorders. This has led to the study of melatonin and melatonin receptor agonists as a primary treatment for nocturia hypothesized to be secondary to sleep disorders. We aim to systematically review the efficacy and reported safety of melatonin and melatonin receptor agonists in the treatment of nocturia.

METHODS

A search strategy of EMBASE and Pubmed/Medline databases was utilized to identify eligible studies. Two thousand and twenty-eight unique references were identified in concordance with the Preferred Reporting Items of Systematic Reviews and Meta-Analyses guidelines for systematic reviews, of which nine papers met the inclusion criteria. The Cochrane Collaboration risk of bias criteria in the open label and nonplacebo studies was used to assess bias.

RESULTS

The nine studies identified included 3 randomized double-blinded placebo-controlled trials, 2 randomized non-placebo trial, and 4 prospective open-label trials. Three utilized the melatonin-receptor agonist ramelteon (8 mg) and six utilized melatonin (four 2 mg extended release, two 2 mg normal release). Nocturia improved in 8 studies varying from moderate to low efficacy related to reduction in nocturia episodes. Five studies evaluated sleep parameters finding improvement in both nocturia and sleep quality. Male subjects represented 76.8% of 371 total subjects in prospective and randomized trials. Ramelteon and melatonin were both reported as well tolerated during nocturia treatment. A meta-analysis was not able to be performed due to the heterogeneity of bladder diagnoses.

CONCLUSIONS

At this time, there is insufficient evidence to routinely recommend melatonin as an effective treatment for nocturia given the limitations of current clinical studies. Randomized placebo-controlled trials and prospective open label studies in non-neurogenic populations report a trend towards nocturia improvement with good tolerability and rare side effects. Therefore, further larger scale randomized trials with focused urologic diagnoses in well-characterized patient populations are warranted.

Melatonin in Alzheimer's Disease: Literature Review and Therapeutic Trials

There are currently no effective treatments to prevent, halt, or reverse Alzheimer's disease (AD), the most common cause of dementia in older adults. Melatonin, a relatively harmless over-the-counter supplement, may offer some benefits to patients with AD. Melatonin is known for its sleep-enhancing properties, but research shows that it may provide other advantages as well, such as antioxidant and anti-amyloidogenic properties. Clinical trials for melatonin use in AD have mixed results but, overall, show modest benefits. However, it is difficult to interpret clinical research in this area as there is little standardization to guide the administration and study of melatonin. This review covers basic biology and clinical research on melatonin in AD focusing on prominent hypotheses of pathophysiology of neurodegeneration and cognitive decline in AD (i.e., amyloid and tau hypotheses, antioxidant and anti-inflammation, insulin resistance and glucose homeostasis, the cholinergic hypothesis, sleep regulation, and the hypothalamic-pituitary-adrenal axis and cortisol). This is followed by a discussion on pending clinical trials, considerations for future research protocols, and open questions in the field.

Efficacy of melatonin and ramelteon for the acute and long-term management of insomnia disorder in adults: A systematic review and meta-analysis

Melatonin has gained growing interest as a treatment of insomnia, despite contradictory findings, and a low level of evidence. A systematic review and meta-analysis was conducted following PRISMA criteria, to assess the efficacy of melatonin and ramelteon compared with placebo on sleep quantity and quality in insomnia disorder, while also considering factors that may impact their efficacy. This review included 22 studies, with 4875 participants, including 925 patients treated with melatonin, 1804 treated with ramelteon and 2297 receiving a placebo. Most studies evaluated the acute efficacy of prolonged release (PR) melatonin in insomnia disorder. Compared with placebo, PR melatonin appears efficacious with a small to medium effect size on subjective sleep onset latency (sSOL) (p = 0.031; weighted difference = -6.30 min), objective sleep onset latency (oSOL) (p < 0.001; weighted difference = -5.05 min), and objective sleep efficiency (oSE) (p = 0.043; weighted difference = 1.91%). For the subgroup mean age of patients ≥55, PR melatonin was efficacious on oSE with a large effect size (p < 0.001; weighted difference = 2.95%). Ramelteon was efficacious with a large effect size at 4 weeks on objective total sleep time (oTST) (p = 0.010; weighted difference = 17.9 min), subjective total sleep time (sTST) (p = 0.006; weighted difference = 11.7 min), sSOL (p = 0.009; weighted difference = -8.74 min), and oSOL (p = 0.017; weighted difference = -14 min). Regarding long-term effects, ramelteon has a large effect size on oTST (p < 0.001; weighted difference = 2.02 min) and sTST (p < 0.001; weighted difference = 14.5 min). PR melatonin and ramelteon appear efficacious compared with placebo for insomnia symptoms with PR melatonin showing mostly small to medium effect sizes. PR melatonin for individuals with a mean age ≥ 55 and ramelteon show larger effect sizes.

Short-Wavelength Light-Blocking Filters and Oral Melatonin Administration in Patients With Retinitis Pigmentosa: Protocol for a Randomized Controlled Trial

BACKGROUND

The medical community is beginning to recognize that retinitis pigmentosa (RP), due to its disabling progression, eventually leads to a reduction in the patient´s quality of life, a direct economic impact, and an increase in the burden on the health care system. There is no curative treatment for the origin of the disease, and most of the current interventions fail in reducing the associated negative psychological states, such as anxiety and depression, which lead to increased variability of vision and pose a continuous threat to the patient's independence.

OBJECTIVE

The aim of this study is to assess the effect of oral melatonin (OM) administration alone and combined with short-wavelength light (SWL)-blocking filters on patients with RP and test their effectiveness in improving the level of stress and sleep problems in many of these patients.

METHODS

We have developed a low-cost therapy protocol for patients with RP with sleep disorders and negative psychological stress. Patients will be randomized to receive a combined intervention with SWL-blocking filters and OM, SWL-blocking filters alone, or OM alone. There will also be a nonintervention arm as a control group. This study will be conducted across 2 retinal units in patients with RP with sleep disorders and high perceived stress and anxiety score reports. Patients will be assessed in the preintervention period, weekly during the 4 weeks of intervention, and then at 6 months postintervention. The primary outcomes are the differences in changes from baseline to postintervention in hormone release (α-amylase, cortisol, and melatonin) and sleep quality, as measured with the visual analog scale. Secondary outcome measures include clinical macular changes, as measured with optical coherence tomography and optical coherence tomography angiography; retinal function, as measured using the visual field and best-corrected visual acuity; sleep data collected from personal wearables; and several patient-reported variables, such as self-recorded sleep diaries, quality of life, perceived stress, and functional status.

RESULTS

This project is still a study protocol and has not yet started. Bibliographic research for information for its justification began in 2020, and this working group is currently seeking start-up funding. As soon as we have the necessary means, we will proceed with the registration and organization prior to the preliminary phase.

CONCLUSIONS

In this feasibility randomized clinical controlled trial, we will compare the effects of SWL blocking alone, administration of OM alone, and a combined intervention with both in patients with RP. We present this study so that it may be replicated and incorporated into future studies at other institutions, as well as applied to additional inherited retinal dystrophies. The goal of presenting this protocol is to aid recent efforts in reducing the impact of sleeping disorders and other psychological disorders on the quality of life in patients with RP and recovering their self-autonomy. In addition, the results of this study will represent a significant step toward developing a novel low-cost therapy for patients with RP and validating a novel therapeutic target.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/49196.

Low Doses of Melatonin to Improve Sleep in Children with ADHD: An Open-Label Trial

OBJECTIVE

Only a few studies assessing the sleep effects of low doses of melatonin (aMT) have been performed in the past, most of them in adults, and only one in subjects with attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to provide evidence of the changes induced by aMT doses as low as 1 mg in the sleep pattern of pediatric patients with ADHD under treatment with methylphenidate (MPH).

METHODS

Children and adolescents (7-15 years) with ADHD who were receiving extended-release MPH were recruited. A seven-week sleep diary was collected prior to starting a four-week treatment with 1 mg of aMT (30 min before bedtime). Seven-day actigraphic assessments of sleep were performed before and after treatment.

RESULTS

Twenty-seven patients (17 males, 62.96%) participated in the study, who had been receiving MPH for 1.57 (1.11) months. A significant increase in sleep duration (TST) was observed after one month of treatment (463 (49) min to 485 (41) min; p < 0.040), with nonsignificant improvements in sleep-onset latency (SOL), nocturnal awakenings, or sleep efficiency. Only minor adverse effects were reported.

CONCLUSION

Low doses of melatonin (1 mg) are able to increase TST in children and adolescents with ADHD receiving treatment with psychostimulants, with an adequate tolerability profile. Further placebo-controlled trials adjusting the time of aMT administration to the individual circadian profile should explore the effects of low doses of this hormone to shorten SOL in this population of patients.

Evaluation of the Anxiolytic Effect of Ramelteon in Various Rat Models of Anxiety

Background Melatonin was found to have anxiolytic properties in several animal and human studies. The melatonin receptor agonist ramelteon might also have a similar anxiolytic action. Objectives The objective of the study was to evaluate the effect of ramelteon in various rat models of anxiety and to explore the possible mechanism of action. Methods The anxiolytic effect was compared between the control group, diazepam group (1 mg/kg and 0.5 mg/kg), and ramelteon group (0.25 mg/kg, 0.5 mg/kg, and 1 mg/kg) by an elevated plus maze, light-dark box, hole board apparatus, and open field test in Sprague Dawley rats. Antagonists flumazenil, picrotoxin, and Luzindole were used to explore the possible mechanism of action of ramelteon if it showed an anxiolytic property. Results Ramelteon as a standalone drug did not show an anxiolytic effect. However, a combination of ramelteon (1 mg/kg) and diazepam (0.5 mg/kg) showed an anxiolytic effect. Conclusion Further studies can evaluate the use of a fixed-dose combination of ramelteon and already-approved anxiolytic drugs to reduce the dose of the latter.

Effectiveness of melatonin for the treatment of nocturia: a randomized controlled trial

INTRODUCTION AND HYPOTHESIS

Nocturia affects health and quality of life (QoL). Current medical treatments can cause severe adverse effects, especially when treating elderly patients. Endogenous melatonin has a physiologic role in urinary bladder function, and the exogenous one may be beneficial for this condition. This article aims to evaluate the effectiveness and safety of melatonin for ameliorating nocturia in older women.

METHODS

This randomized, double-blind, placebo-controlled trial was conducted at a university hospital in Thailand. Sixty women with nocturia, aged > 55 years, were prospectively recruited and were later randomly allocated to treatment (melatonin 2 mg/day, n = 30) and control (placebo, n = 30) arms for 2 weeks. Outcome measures included nocturia episodes, nocturia-related parameters, Nocturia Quality of Life Questionnaire (N-QoL) scores, and adverse events.

RESULTS

The treatment and control groups were comparable in mean age (65.9 + 7.5 vs. 68.5 + 6.3 years). Both groups had comparable causes of nocturia with a baseline median voiding frequency of 2.3 (1.3, 6.3) and 2.3 (1.7, 5.3) episodes/night, respectively. The treatment group had significantly better outcomes than the placebo group in terms of median reduction in nocturia [-1.0 (-3.0, 0.0) vs. 0.0 (-2.3, 1.3) episodes/night; p < 0.001], increased median duration of the first uninterrupted sleep [1.0 (-0.3, 4.5) vs. 0.0 (-3.0, 2.3) h; p < 0.001], and improvement in N-QoL scoring, especially in the sleep/energy subscale (p = 0.019) and the total score (p = 0.016). Adverse events were comparable between groups.

CONCLUSIONS

Melatonin can be considered a safe and effective treatment for nocturia in elderly women.

Melatonin as a Chronobiotic with Sleep-promoting Properties

The use of exogenous melatonin (exo-MEL) as a sleep-promoting drug has been under extensive debate due to the lack of consistency of its described effects. In this study, we conduct a systematic and comprehensive review of the literature on the chronobiotic, sleep-inducing, and overall sleep-promoting properties of exo-MEL. To this aim, we first describe the possible pharmacological mechanisms involved in the sleep-promoting properties and then report the corresponding effects of exo-MEL administration on clinical outcomes in: a) healthy subjects, b) circadian rhythm sleep disorders, c) primary insomnia. Timing of administration and doses of exo-MEL received particular attention in this work. The exo-MEL pharmacological effects are hereby interpreted in view of changes in the physiological properties and rhythmicity of endogenous melatonin. Finally, we discuss some translational implications for the personalized use of exo-MEL in the clinical practice.

Efficacy of melatonin for chronic insomnia: Systematic reviews and meta-analyses

We conducted systematic reviews and meta-analyses to evaluate the efficacy of melatonin versus placebo or other hypnotic agents in improving sleep quality and quantity in patients with chronic insomnia. A literature search on Ovid-MEDLINE, EMBASE, and the Cochrane Library was performed up to November 2020. Sleep onset latency, total sleep time, sleep efficiency, sleep quality and quality of life were examined as outcomes. We identified 24 randomized controlled trials of chronic insomnia including four studies of patients with comorbid insomnia. All studies were compared with placebo. Due to heterogeneity, we conducted subgroup analyses by age group. In non-comorbid insomnia, melatonin was only significantly effective in sleep onset latency and total sleep time in children and adolescents. In adults group, melatonin was not significantly effective in improving sleep onset latency, total sleep time, and sleep efficiency. In comorbid insomnia, melatonin significantly improved sleep onset latency in all age groups, but there was only one study in adults group. In conclusion, melatonin did not appear to be effective in adults but might be effective in children and adolescents with chronic insomnia for both comorbid insomnia and non-comorbid insomnia. Further studies are needed to establish the efficacy and safety of melatonin by age groups.

Use of Melatonin and/on Ramelteon for the Treatment of Insomnia in Older Adults: A Systematic Review and Meta-Analysis

To investigate the efficacy of melatonin and/or ramelteon reporting sleep outcomes for older adults with chronic insomnia, a systematic review and a meta-analysis of PubMed, EMBASE, Cochrane library, International Pharmaceutical Abstracts, PsycINFO, science citation index, center for reviews and dissemination, CINAHL, grey literature and relevant sleep journal searches were conducted from 1 January 1990 to 20 June 2021. Randomized controlled trials and other comparative studies with melatonin and/or ramelteon use among older patients with chronic insomnia were included. Funnel plot and Egger’s test was used to determine publication bias. A forest plot was constructed to obtain a pooled standardized mean difference using either a fixed or random effects model for each of the two broad categories of sleep outcomes: objective and subjective. Of 5247 studies identified, 17 studies met the inclusion criteria for MA. Study sample size ranged from 10 to 829 with the mean age ≥55 years. There were significant improvements in total sleep time (objective), sleep latency and sleep quality (objective and subjective) for melatonin and/or ramelteon users compared with placebo. Sleep efficiency was not significantly different. The effects of these agents are modest but with limited safe treatment options for insomnia in older adults, these could be the drugs of choice.

Emergency Medicine Personnel's Preparation, Performance and Perception of Their Night Shifts: A Cross-Sectional Study from Saudi Arabia

PURPOSE

This study aimed to investigate the perceptions and habits of different emergency department (ED) workers (nurses, residents, and attending physicians) and their pre- or post-shift routines. The study also examined the effect of night shifts on personal life, social life, and health.

PATIENTS AND METHODS

An anonymous, online, cross-sectional, multiple-choice, self-rating (5-point Likert scale) survey was administered to the participants. All analyses were performed using the SPSS version 22.0. Ethical approval was obtained from the Institutional Review Board (IRB) of King Saud University Medical City (KSUMC) in Riyadh, Saudi Arabia.

RESULTS

Thirty-three nurses, 51 residents, and 39 attending physicians participated in the survey (response rates of 21%, 100%, and 100%, respectively). A significant difference was noted in the need to use physical sleeping aids between the three groups (P < 0.003), with more nurses using humidifiers as a sleeping aid (21.2%) than residents or attending physicians. However, there was no difference in the use of pharmacological aids between the three groups. All groups utilized coffee as the preferred stimulant, especially residents (76.5%, P <0.032). Nurses and attending physicians wake up 2 hours before their shift, while residents prefer 3 hours (P <0.001). Attending physicians reported the highest accident rates post-night shifts of 17.9% (P < 0.001). Residents reported satisfaction while working night shifts and were least in agreement with night shifts reducing life span. Attending physicians were more in agreement with the increasing risk of drug/alcohol misuse and the incidence of depression in relation to night shifts.

CONCLUSION

Participants shared many commonalities, yet residents were less likely to use sleeping aids and enjoy night shifts more than the other groups. All groups consumed coffee for stimulation. Attending physicians reported the highest accident rates post night shifts.

What do we really know about the safety and efficacy of melatonin for sleep disorders?

Melatonin is a hormonal product of the pineal gland, a fact that is often forgotten. Instead it is promoted as a dietary supplement that will overcome insomnia, as an antioxidant and as a prescription only drug in most countries outside the United States of America and Canada. The aim of this review is to step back and highlight what we know about melatonin following its discovery 60 years ago. What is the role of endogenous melatonin; what does melatonin do to sleep, body temperature, circadian rhythms, the cardiovascular system, reproductive system, endocrine system and metabolism when administered to healthy subjects? When used as a drug/dietary supplement, what safety studies have been conducted? Can we really say melatonin is safe when it has not been systematically studied and many studies show interactions with a wide range of physiological processes? Finally the results of studies investigating the efficacy of melatonin as a drug to alleviate insomnia are critically evaluated. In summary, melatonin is an endogenous pineal gland hormone with specific physiological functions in animals and humans, with its primary role in humans to maintain synchrony of sleep with the day/night cycle. When administered as a drug it affects a wide range of physiological systems and has clinically important drug interactions. With respect to efficacy for treating sleep disorders, melatonin can advance the time of sleep onset but the effect is modest and variable. In children with neurodevelopmental disabilities melatonin appears to have the greatest impact on sleep onset but little effect on sleep efficiency.

Beneficial Effect of Melatonin on Motor and Memory Disturbances in 6-OHDA-Lesioned Rats

Previous evidence has shown a link between neurodegenerative diseases, including Parkinson's disease (PD), and melatonin. The data in the literature about the impact of the hormone under different experimental PD conditions are quite controversial, and its effect on memory impairment in the disease is very poorly explored. The current research was aimed at investigating the role of melatonin pretreatment on memory and motor behavior in healthy rats and those with the partial 6-hydroxydopamine (6-OHDA) model of PD. All rodents were pretreated with melatonin (20 mg/kg, intraperitoneally) for 5 days. At 24 h and 7 days after the first treatment for healthy rats, and at the second and third week post-lesion for those with PD, the animals were tested behaviorally (apomorphine-induced rotations, rotarod, and passive avoidance tests). The neurochemical levels of dopamine (DA), acetylcholine (ACh), noradrenaline (NA), and serotonin (Sero) in the brain were also determined. The results showed that in healthy animals, melatonin pretreatment had amnestic and motor-suppressive effects and did not change the levels of measured brain neurotransmitters. In animals with PD, melatonin pretreatment exerted a neuroprotective effect, manifested as a significantly decreased number of apomorphine-induced rotations, reduced number of falls in the rotarod test, and improved memory performance. The brain DA and ACh concentrations in the same animals were restored to the control levels, and those of NA and Sero did not change. Our results demonstrate a beneficial effect of melatonin on memory and motor disturbance in 6-OHDA-lesioned rats.

Low-dose melatonin for sleep disturbances in early-stage cirrhosis: A randomized, placebo-controlled, cross-over trial

Background and aim

Melatonin is used to treat sleep disturbances (SDs). The aim of this study was to investigate the safety and efficacy of low‐dose melatonin for SDs in early‐stage cirrhosis.

Methods

In a single‐center, randomized, double‐blind, placebo‐controlled, cross‐over clinical trial, patients with early‐stage (Child‐Turcotte‐Pugh [CTP] class A or B) cirrhosis with SDs, without hepatic encephalopathy, were randomized to placebo or 3 mg of melatonin for 2 weeks. After 2 weeks, the patients were given a washout period of 1 week and crossed over to melatonin or placebo for a further 2 weeks. The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) were used to measure sleep quality and daytime sleepiness, respectively. Analysis of results was based on intention to treat, and linear mixed‐effect models were used to evaluate the effect of melatonin. Analysis was conducted using R‐programming language 3.5.1.

Results

Seventy one patients were recruited (mean age: 61.9 ± 8.7 years, males: 46 [64.8%], and CTP Class A = 52 [73.2%] and Class B = 19 [26.8%]). Sixty patients completed the study (mean age: 61.7 ± 8.8 years, males: 40 [66.6%], and CTP Class A = 45 [75.0%] and Class‐B = 15 [25.0%]). Two patients dropped out due to adverse events. Nine patients were lost to follow up. Patients given melatonin had a significantly lower PSQI and ESS compared to both pretreatment (P < 0.001) and postplacebo scores (P < 0.001). Incidence of adverse events was similar (two each of abdominal pain, one each of headache, one each of dizziness) in both groups.

Conclusion

Melatonin seems safe and effective for use in patients with SDs in early‐stage cirrhosis in the short term. However, larger and longer‐term studies to assess efficacy and safety are required before its clinical use can be recommended.

Public health impact and treatment of insomnia

A growing number of people are concerned about their sleep in the United States. There are an estimated 40 million US citizens with chronic sleep disorders. The cost to society of sleep disorders has been estimated at greater than $90 billion US dollars. Despite this enormous cost to society, there remains a pervasive lack of attention provided to medical management of this problem. This is compounded by inadequate funding of sleep disorders research. There are treatments available to improve insomnia. These include different behavioral and pharmacologic regimes that can be used separately or in combination. Successful treatment requires thorough knowledge of the differential diagnosis of insomnia. The greatest public health challenge in the management of insomnia is how to develop effective educational programs that will allow the general public to improve their sleep. This will require greater cooperation from primary care providers and the government. Sleep disorders are the most important public health problem not being addressed in the United States.

Regulation of Circadian Clock Genes on Sleep Disorders in Traumatic Brain Injury Patients

BACKGROUND

In patients with traumatic brain injury (TBI), whether sleep disorder is associated with disturbances in molecular rhythmicity is unclear. This study aimed to investigate the relationship between abnormal sleep and regulation by circadian rhythms in patients with TBI.

METHODS

We sampled buccal cells and human blood samples from patients with TBI diagnosed with sleep disorders and those with normal sleep and investigated differences in the expression levels of Clock, Per2, and Bmal1 between the 2 groups.

RESULTS

The expression peaks of Clock, Per2, and Bmal1 were at 12:00. There was a statistically significant difference between the sleep disorder group and the normal sleep group in the level of Clock mRNA expression (P = 0.0003 in oral mucosa and P < 0.0001 in mononuclear cells). There was no significant between-group difference in Bmal1 mRNA expression level (P = 0.1187 in oral mucosa and P = 0.2094 in mononuclear cells). There were significant between-group differences in Per2 mRNA expression levels at 12:00 (P = 0.0102 in oral mucosa and P = 0.0006 in mononuclear cells) and 18:00 (P = 0.0004 in oral mucosa and P = 0.0015 in mononuclear cells) but no significant difference at 24:00 (P = 0.7838 in oral mucosa and P = 0.2808 in mononuclear cells).

CONCLUSIONS

Abnormal expression levels of Per2, Clock, and Bmal1 were detected in patients with TBI-related sleep disorders. These novel findings demonstrate disturbances in the molecular clock in TBI patients and have important implications for our understanding of the aberrant rhythms reported in this disease.

Sleep as a Therapeutic Target in the Aging Brain

Sleep is a behavioral phenomenon conserved among mammals and some invertebrates, yet the biological functions of sleep are still being elucidated. In humans, sleep time becomes shorter, more fragmented, and of poorer quality with advancing age. Epidemiologically, the development of age-related neurodegenerative diseases such as Alzheimer's and Parkinson's disease is associated with pronounced sleep disruption, whereas emerging mechanistic studies suggest that sleep disruption may be causally linked to neurodegenerative pathology, suggesting that sleep may represent a key therapeutic target in the prevention of these conditions. In this review, we discuss the physiology of sleep, the pathophysiology of neurodegenerative disease, and the current literature supporting the relationship between sleep, aging, and neurodegenerative disease.

Effects of Melatonin Ingestion Before Nocturnal Sleep on Postural Balance and Subjective Sleep Quality in Older Adults

The present study aimed to investigate the effect of acute nocturnal melatonin (MEL) ingestion on sleep quality, cognitive performance, and postural balance in older adults. A total of 12 older men (58 ± 5.74 years) volunteered to participate in this study. The experimental protocol consisted in two testing sessions after nocturnal MEL (10 mg) or placebo ingestion the night before the tests. During each session, sleep quality tests, cognitive tests, and postural balance protocol were conducted. Static and dynamic postural control was assessed using a force platform. Most of the sleep parameters have been improved following nocturnal MEL ingestion without any effect on cognitive performance. Likewise, measurements related to the center of pressure (CoP) have been significantly decreased with MEL compared with placebo. In conclusion, postural control has been improved the morning following nocturnal MEL ingestion in older adults. This trend could be explained by the potential effect of MEL on sleep quality and cerebellum.

Association of the melatonin circadian rhythms with clock 3111T/C gene polymorphism in Caucasian and Asian menopausal women with insomnia

A comparative analysis of melatonin circadian rhythms in Caucasian (incoming population) and Asian (indigenous population) menopausal women with/without sleep disorders depending on the genotype of Clock 3111T/C gene polymorphism was realized.The melatonin level in the saliva was determined four times a day (6:00-7:00, 12:00-13:00, 18:00-19:00, 23:00-00:00 h). The Caucasian women-carriers of the TT-genotype with insomnia as compared to control group-had a higher morning melatonin level and a lower night melatonin level. The Asian women with TT-genotype and insomnia had a lower levels of melatonin as compared to control at daytime, evening and night. A significantly higher melatonin level in the early morning hours was detected in the Caucasian women-carriers of the TT-genotype with insomnia as compared to group womencarriers of the minor 3111C-allele. There were no statistically significant differences in the circadian rhythms of melatonin in the Asian women depending on the genotype of the Clock 3111T/C polymorphism. An assumption with respect to the protective role of the minor allele 3111C in the development of insomnia associated with the displacement of melatonin circadian rhythms in the representatives of the incoming population was made.

Efficacy of melatonin for sleep disturbance following traumatic brain injury: a randomised controlled trial

BACKGROUND

The study aimed to determine the efficacy of melatonin supplementation for sleep disturbances in patients with traumatic brain injury (TBI).

METHODS

This is a randomised double-blind placebo-controlled two-period two-treatment (melatonin and placebo) crossover study. Outpatients were recruited from Epworth and Austin Hospitals Melbourne, Australia. They had mild to severe TBI (n = 33) reporting sleep disturbances post-injury (mean age 37 years, standard deviation 11 years; 67% men). They were given prolonged-release melatonin formulation (2 mg; Circadin®) and placebo capsules for 4 weeks each in a counterbalanced fashion separated by a 48-hour washout period. Treatment was taken nightly 2 hours before bedtime. Serious adverse events and side-effects were monitored.

RESULTS

Melatonin supplementation significantly reduced global Pittsburgh Sleep Quality Index scores relative to placebo, indicating improved sleep quality [melatonin 7.68 vs. placebo 9.47, original score units; difference -1.79; 95% confidence interval (CI), -2.70 to -0.88; p ≤ 0.0001]. Melatonin had no effect on sleep onset latency (melatonin 1.37 vs. placebo 1.42, log units; difference -0.05; 95% CI, -0.14 to 0.03; p = 0.23). With respect to the secondary outcomes, melatonin supplementation increased sleep efficiency on actigraphy, and vitality and mental health on the SF-36 v1 questionnaire (p ≤ 0.05 for each). Melatonin decreased anxiety on the Hospital Anxiety Depression Scale and fatigue on the Fatigue Severity Scale (p ≤ 0.05 for both), but had no significant effect on daytime sleepiness on the Epworth Sleepiness Scale (p = 0.15). No serious adverse events were reported.

CONCLUSIONS

Melatonin supplementation over a 4-week period is effective and safe in improving subjective sleep quality as well as some aspects of objective sleep quality in patients with TBI.

TRIAL REGISTRATION

Identifier: 12611000734965; Prospectively registered on 13 July 2011.

Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline

INTRODUCTION

The purpose of this guideline is to establish clinical practice recommendations for the pharmacologic treatment of chronic insomnia in adults, when such treatment is clinically indicated. Unlike previous meta-analyses, which focused on broad classes of drugs, this guideline focuses on individual drugs commonly used to treat insomnia. It includes drugs that are FDA-approved for the treatment of insomnia, as well as several drugs commonly used to treat insomnia without an FDA indication for this condition. This guideline should be used in conjunction with other AASM guidelines on the evaluation and treatment of chronic insomnia in adults.

METHODS

The American Academy of Sleep Medicine commissioned a task force of four experts in sleep medicine. A systematic review was conducted to identify randomized controlled trials, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence. The task force developed recommendations and assigned strengths based on the quality of evidence, the balance of benefits and harms, and patient values and preferences. Literature reviews are provided for those pharmacologic agents for which sufficient evidence was available to establish recommendations. The AASM Board of Directors approved the final recommendations.

RECOMMENDATIONS

The following recommendations are intended as a guideline for clinicians in choosing a specific pharmacological agent for treatment of chronic insomnia in adults, when such treatment is indicated. Under GRADE, a STRONG recommendation is one that clinicians should, under most circumstances, follow. A WEAK recommendation reflects a lower degree of certainty in the outcome and appropriateness of the patient-care strategy for all patients, but should not be construed as an indication of ineffectiveness. GRADE recommendation strengths do not refer to the magnitude of treatment effects in a particular patient, but rather, to the strength of evidence in published data. Downgrading the quality of evidence for these treatments is predictable in GRADE, due to the funding source for most pharmacological clinical trials and the attendant risk of publication bias; the relatively small number of eligible trials for each individual agent; and the observed heterogeneity in the data. The ultimate judgment regarding propriety of any specific care must be made by the clinician in light of the individual circumstances presented by the patient, available diagnostic tools, accessible treatment options, and resources. We suggest that clinicians use suvorexant as a treatment for sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use eszopiclone as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use zaleplon as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use zolpidem as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use triazolam as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use temazepam as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use ramelteon as a treatment for sleep onset insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians use doxepin as a treatment for sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use trazodone as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use tiagabine as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use diphenhydramine as a treatment for sleep onset and sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use melatonin as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use tryptophan as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK). We suggest that clinicians not use valerian as a treatment for sleep onset or sleep maintenance insomnia (versus no treatment) in adults. (WEAK).

Sleep, Melatonin, and the Menopausal Transition: What Are the Links?

The pineal hormone Melatonin plays an important role in the regulation of the circadian sleep/wake cycle, mood, and perhaps immune functions, carcinogensis and reproduction. The human circadian rhythm of melatonin release from the pineal gland is tightly synchronized with the habitual hours of sleep. Peri- and postmenopausal women often complain of difficulties initiating and/or maintaining sleep, with frequent nocturnal and early morning awakenings. In this review we discuss the pathophysiology of melatonin function as it relates to sleep disorders in menopausal women, highlighting the potential use of exogenous melatonin during the menopausal transition and beyond.

The Efficacy of Oral Melatonin in Improving Sleep in Cancer Patients with Insomnia: A Randomized Double-Blind Placebo-Controlled Study

BACKGROUND

The natural hormone melatonin has sleep inducing properties. Insomnia in cancer patients is common. So far, melatonin has been seldom tried for the improvement of sleep in patients with malignancies. Keeping this in mind, we planned and conducted a double-blind study to test the efficacy of melatonin in promoting sleep in patients with malignancies suffering from insomnia.

OBJECTIVE

To assess the hypnotic efficacy of oral melatonin in cancer patients with insomnia.

MATERIALS AND METHODS

After Ethical Committee approval, 50 patients (age range 20-65 years) from our pain clinic NIVARANE who met the Diagnostic and Statistical Manual of Mental Disorders 4(th) edition criteria for primary insomnia were randomized to receive melatonin 3 mg or placebo at 7 pm orally every day for 14 days from our pharmacist. After 1, 7, 14 days, the patients were reviewed with the Athens insomnia scale oral questionnaire to document the subjective sleep quality. The patients and we, the investigators were blinded to the study drug.

RESULTS

There were 2 drop outs (one from each group) as they failed to complete visit on day 14. Significant differences in favor of melatonin treatment were found in clinically relevant improvements in insomnia (46.53%; P = 0.00001 vs. 11.30%; P = 0.1026) There was improvement in sleep from 1 to 7 days (19.91%; P = 0.00001 vs. 0.98%; P = 0.2563). More significant improvements were seen between 7 and 14 days (33.24%; P = 0.00001 vs. 10.42%; P = 0.1469).

CONCLUSION

We conclude that daily intake of oral melatonin 2 h before bedtime improves sleep induction and quality in cancer patients with insomnia.

The potential physiological crosstalk and interrelationship between two sovereign endogenous amines, melatonin and homocysteine

The antioxidant melatonin and the non-proteinogenic excitotoxic amino acid homocysteine (Hcy) are very distinct but related reciprocally to each other in their mode of action. The elevated Hcy level has been implicated in several disease pathologies ranging from cardio- and cerebro-vascular diseases to neurodegeneration owing largely to its free radical generating potency. Interestingly, melatonin administration potentially normalizes the elevated Hcy level, thereby protecting the cells from the undesired Hcy-induced excitotoxicity and cell death. However, the exact mechanism and between them remain obscure. Through literature survey we have found an indistinct but a vital link between melatonin and Hcy i.e., the existence of reciprocal regulation between them, and this aspect has been thoroughly described herein. In this review, we focus on all the possibilities of co-regulation of melatonin and Hcy at the level of their production and metabolism both in basal and in pathological conditions, and appraised the potential of melatonin in ameliorating homocysteinemia-induced cellular stresses. Also, we have summarized the differential mode of action of melatonin and Hcy on health and disease states.

Complementary and integrative medicine for older adults in palliative care

Complementary and Integrative Medicine (CIM) encompasses many diverse therapies, including natural products and mind and body practices. Use of CIM is common and can benefit patients in palliative care. However, because patients in palliative care are often frail and elderly, the clinician should consider a patient's comorbidities before recommending certain therapies, such as natural products. In this article, specific examples of CIM are provided for symptoms commonly seen in palliative care.

Melatonin, the Hormone of Darkness: From Sleep Promotion to Ebola Treatment

Melatonin is a hormone secreted by the enigmatic pineal gland in response to darkness, hence the name hormone of darkness. It has generated a great deal of interest as a therapeutic modality for various diseases particularly sleep disorders. This pleiotropic molecule has anti-inflammatory, antioxidant and anticoagulopathic properties in addition to its endothelial protective effects. In this article we discuss melatonin secretion and mechanisms of action as well as therapeutic rationale. We also highlight the potential utility of melatonin in the deadly modern-day Ebola epidemic.

Role in therapy of melatonin for the treatment of insomnia in children and adults

Melatonin is an endogenous indolamine produced by the pineal gland which may have a role in the biological regulation of circadian rhythms, sleep, and mood. Melatonin receptor activation in the hypothalamus likely regulates circadian rhythms. In the United States, melatonin is marketed as a dietary supplement. Clinical trials in children and adults have shown modest clinical benefit in the treatment of insomnia. Adverse events reported in patients receiving melatonin were not significantly different in type or occurrence from those reported in patients receiving placebo. Considering the potential for benefit, lack of significant adverse events, and lack of abuse potential, melatonin may be considered a valid therapeutic option for improving outcomes in certain pediatric and adult patients with insomnia.

Optimizing the Pharmacologic Treatment of Insomnia: Current Status and Future Horizons

A number of medications are available for treating patients with insomnia. These medications include agents approved as insomnia therapies by the U.S. Food and Drug Administration (FDA), agents approved by the FDA for another condition that are used "off-label" to treat insomnia, and agents available "over-the-counter" that are taken by individuals with insomnia. These agents differ in their properties, their safety and efficacy when used for different insomnia patient subtypes, and the available data on their efficacy and safety in these subtypes. As a result, optimizing the medication treatment of insomnia for a given patient requires that the clinician select an agent for use which has characteristics that make it most likely to effectively and safely address the type of sleep difficulty experienced by that individual. This article is intended to assist clinicians and researchers in carrying out this optimization. It begins by reviewing the basic characteristics of the medications used to treat insomnia. This is followed by a review of the fundamental ways that individuals with insomnia may differ and affect the choice of medication therapy. This review includes discussions that illustrate how to best choose a medication based on the characteristics of the available medications, the key differences among insomnia patients, and the available research literature. Lastly, we discuss future directions for the optimizing pharmacologic management of insomnia. It is hoped that the treatment tailoring methods discussed herein serve as a means of improving the clinical management of insomnia and, thus, improve the lives of the many patients who suffer from this common and impairing condition.

Meta-analysis: melatonin for the treatment of primary sleep disorders

STUDY OBJECTIVES

To investigate the efficacy of melatonin compared to placebo in improving sleep parameters in patients with primary sleep disorders.

DESIGN

PubMed was searched for randomized, placebo-controlled trials examining the effects of melatonin for the treatment of primary sleep disorders. Primary outcomes examined were improvement in sleep latency, sleep quality and total sleep time. Meta-regression was performed to examine the influence of dose and duration of melatonin on reported efficacy.

PARTICIPANTS

Adults and children diagnosed with primary sleep disorders.

INTERVENTIONS

Melatonin compared to placebo.

RESULTS

Nineteen studies involving 1683 subjects were included in this meta-analysis. Melatonin demonstrated significant efficacy in reducing sleep latency (weighted mean difference (WMD) = 7.06 minutes [95% CI 4.37 to 9.75], Z = 5.15, p<0.001) and increasing total sleep time (WMD = 8.25 minutes [95% CI 1.74 to 14.75], Z = 2.48, p = 0.013). Trials with longer duration and using higher doses of melatonin demonstrated greater effects on decreasing sleep latency and increasing total sleep time. Overall sleep quality was significantly improved in subjects taking melatonin (standardized mean difference = 0.22 [95% CI: 0.12 to 0.32], Z = 4.52, p<0.001) compared to placebo. No significant effects of trial duration and melatonin dose were observed on sleep quality.

CONCLUSION

This meta-analysis demonstrates that melatonin decreases sleep onset latency, increases total sleep time and improves overall sleep quality. The effects of melatonin on sleep are modest but do not appear to dissipate with continued melatonin use. Although the absolute benefit of melatonin compared to placebo is smaller than other pharmacological treatments for insomnia, melatonin may have a role in the treatment of insomnia given its relatively benign side-effect profile compared to these agents.

Pineal melatonin level disruption in humans due to electromagnetic fields and ICNIRP limits

The International Agency for Research on Cancer (IARC) classifies electromagnetic fields (EMFs) as 'possibly carcinogenic' to humans that might transform normal cells into cancer cells. Owing to high utilisation of electricity in day-to-day life, exposure to power-frequency (50 or 60 Hz) EMFs is unavoidable. Melatonin is a natural hormone produced by pineal gland activity in the brain that regulates the body's sleep-wake cycle. How man-made EMFs may influence the pineal gland is still unsolved. The pineal gland is likely to sense EMFs as light but, as a consequence, may decrease the melatonin production. In this study, more than one hundred experimental data of human and animal studies of changes in melatonin levels due to power-frequency electric and magnetic fields exposure were analysed. Then, the results of this study were compared with the International Committee of Non-Ionizing Radiation Protection (ICNIRP) limit and also with the existing experimental results in the literature for the biological effect of magnetic fields, in order to quantify the effects. The results show that this comparison does not seem to be consistent despite the fact that it offers an advantage of drawing attention to the importance of the exposure limits to weak EMFs. In addition to those inconsistent results, the following were also observedfrom this work: (i) the ICNIRP recommendations are meant for the well-known acute effects, because effects of the exposure duration cannot be considered and (ii) the significance of not replicating the existing experimental studies is another limitation in the power-frequency EMFs. Regardless of these issues, the above observation agrees with our earlier study in which it was confirmed that it is not a reliable method to characterise biological effects by observing only the ratio of AC magnetic field strength to frequency. This is because exposure duration does not include the ICNIRP limit. Furthermore, the results show the significance of disruption of melatonin due to exposure to weak EMFs, which may possibly lead to long-term health effects in humans.

Melatonin supplementation in patients with complete tetraplegia and poor sleep

People with complete tetraplegia have interrupted melatonin production and commonly report poor sleep. Whether the two are related is unclear. This pilot study investigated whether nightly supplementation of 3 mg melatonin would improve objective and subjective sleep in tetraplegia. Five participants with motor and sensory complete tetraplegia ingested 3 mg melatonin (capsule) two hours prior to usual sleep time for two weeks. Full portable sleep studies were conducted in participants' homes on the night before commencing melatonin supplementation (baseline) and on the last night of the supplementation period. Endogenous melatonin levels were determined by assaying saliva samples collected the night of (just prior to sleep) and morning after (upon awakening) each sleep study. Prior to each sleep study measures of state sleepiness and sleep behaviour were collected. The results showed that 3 mg of melatonin increased salivary melatonin from near zero levels at baseline in all but one participant. A delay in time to Rapid Eye Movement sleep, and an increase in stage 2 sleep were observed along with improved subjective sleep experience with a reduction in time to fall asleep, improved quality of sleep and fewer awakenings during the night reported. Daytime sleepiness increased however. A randomised, placebo controlled trial with a larger sample is required to further explore and confirm these findings.

Batch variation and pharmacokinetics of oral sustained release melatonin-loaded sugar spheres in human subjects

The three different batches of an oral sustained release melatonin (MT) delivery system were prepared by aqueous-based fluid-bed coating of the sugar spheres for the evaluation ofin vitro release characteristics and plasma concentration profiles in human subjects. The MT contents in 20% coated sugar spheres of three batches (B1, B2 and B3) were 3.3+/-0.08, 2.4+/-0.1 and 2.5+/-0.13 mg per gram of coated sugar spheres, respectively. The release profiles of three different batches had a very similar fashion. However, the release half-lives (T(50%)) of MT from B1, B2 and B3 was 3.70+/-0.2, 5.2+/-0.2 and 4.9+/-0.07h, respectively. Plasma concentration profiles of sustained release 0.2mg melatonin-loaded sugar spheres containing 10% immediate release melatonin in gelatin capsules (B1 and B2) were then evaluated in human subjects. Thein vivo plasma concentration profiles of the two batches (B1 and B2) were very similar each other and located between the physiological endogenous ranges. The time to reach the peak concentration (T(max)) was more advanced in case of B1 when compared to B2. However, there was no statistically significant difference in the maximum concentration (C(max)) and the area under the curve (AUC) between B1 and B2. The AUC of melatonin-loaded sugar spheres containing 10% and 20% immediate release MT in human subjects had a good linearity between dose and AUC, regardless of the fraction of immediate release MT, indicating the first order elimination process of MT within these doses. The current oral sustained release MT delivery system may be utilized to treat circadian rhythm disorders if it is proven to be more clinically useful when compared to immediate release MT.

Pharmacotherapy of insomnia

INTRODUCTION

Insomnia is one of the most prevalent sleep disorders in developed countries, being surpassed only by chronic sleep deprivation. Patients with insomnia tend to have an altered quality of life, impaired daytime functioning and an increased risk of work accidents and motor vehicle crashes. Insomnia is commonly associated with chronic medical conditions, metabolic illnesses and mental disorders (such as depression and anxiety), with which there is a dual, reciprocal relationship.

AREAS COVERED

This paper focuses on current pharmacotherapy options for the treatment of insomnia, particularly benzodiazepine receptor agonists, which nowadays represent the mainstay of hypnotic therapy. The melatonin receptor antagonist, ramelteon, is reviewed (an alternative for some patients with only sleep-onset difficulty), as are sedating antidepressants, which are commonly used 'off-label' to treat insomnia, despite limited efficacy data and potential significant safety concerns. Orexin (OX) antagonists are also discussed, especially those that block OX2 or both OX1 and OX2 receptors, as these are the most promising new agents for the treatment of insomnia, with encouraging results in preliminary clinical trials.

EXPERT OPINION

Research to evaluate and formulate treatments for insomnia is often complicated by the fact that insomnia is usually of multifactorial etiology. Understanding the molecular and receptor mechanisms involved in promoting sleep in varied disorders could provide future approaches in new drug development. In the long term, more randomized controlled trials are needed to assess both short-term and long-term effects of these medications and their efficacy in comorbid diseases that affect sleep quality or quantity.

A novel pathway underlying the inhibitory effects of melatonin on isolated rat urinary bladder contraction

The aim of the present study was to elucidate the direct effects of melatonin on bladder activity and to determine the mechanisms responsible for the detrusor activity of melatonin in the isolated rat bladder. We evaluated the effects of melatonin on the contractions induced by phenylephrine (PE), acetylcholine (ACh), bethanechol (BCh), KCl, and electrical field stimulation (EFS) in 20 detrusor smooth muscle samples from Sprague-Dawley rats. To determine the mechanisms underlying the inhibitory responses to melatonin, melatonin-pretreated muscle strips were exposed to a calcium channel antagonist (verapamil), three potassium channel blockers [tetraethyl ammonium (TEA), 4-aminopyridine (4-AP), and glibenclamide], a direct voltage-dependent calcium channel opener (Bay K 8644), and a specific calcium/calmodulin-dependent kinase II (CaMKII) inhibitor (KN-93). Melatonin pretreatment (10^-8~10^-6 M) decreased the contractile responses induced by PE (10^-9~10^-4 M) and Ach (10^-9~10^-4 M) in a dose-dependent manner. Melatonin (10^-7 M) also blocked contraction induced by high KCl ([KCl]_ECF; 35 mM, 70 mM, 105 mM, and 140 mM) and EFS. Melatonin (10^-7 M) potentiated the relaxation response of the strips by verapamil, but other potassium channel blockers did not change melatonin activity. Melatonin pretreatment significantly decreased contractile responses induced by Bay K 8644 (10^-11~10^-7 M). KN-93 enhanced melatonin-induced relaxation. The present results suggest that melatonin can inhibit bladder smooth muscle contraction through a voltage-dependent, calcium-antagonistic mechanism and through the inhibition of the calmodulin/CaMKII system.

Mood disorders, circadian rhythms, melatonin and melatonin agonists

Recent advances in the understanding of circadian rhythms have led to an interest in the treatment of major depressive disorder with chronobiotic agents. Many tissues have autonomous circadian rhythms, which are orchestrated by the master clock, situated in the suprachiasmatic nucleus (SNC). Melatonin (N-acetyl-5-hydroxytryptamine) is secreted from the pineal gland during darkness. Melatonin acts mainly on MT1 and MT2 receptors, which are present in the SNC, regulating physiological and neuroendocrine functions, including circadian entrainment, referred to as the chronobiotic effet. Circadian rhythms has been shown to be either misaligned or phase shifted or decreased in amplitude in both acute episodes and relapse of major depressive disorder (MDD) and bipolar disorder. Manipulation of circadian rhythms either using physical treatments (such as high intensity light) or behavioral therapy has shown promise in improving symptoms. Pharmacotherapy using melatonin and pure melatonin receptor agonists, while improving sleep, has not been shown to improve symptoms of depression. A novel antidepressant, agomelatine, combines 5HT2c antagonist and melatonin agonist action, and has shown promise in both acute treatment of MDD and in preventing relapse.