Melatonin's role as an anticonvulsant and neuronal protector: experimental and clinical evidence

Twenty-four-hour pattern of children with febrile seizures presenting to a United States Pediatric Emergency Department

BACKGROUND

Febrile seizure (FS) is the most common convulsive disorder in children. Understanding its time-of-day pattern can provide insight into mechanisms and prevention.

PURPOSE

We explored clock-time variation of FS presentations of children to a US pediatric emergency department (PED) in comparison to two control cohorts: one (n = 5719) like-aged children presenting solely with fever, i.e., temperature > 100.4 °F/38°C, and one of children (n = 103,806) presenting for any medical emergency.

METHODS

Electronic medical records covering a 58-month span were searched for clock time of arrivals to the PED, with data assessed either by chi-square or Cosinor analyses to test for temporal variation and derive descriptive parameters.

MAJOR FINDINGS

Presentation of the 84 FS cases exhibited a time-of-day difference (p = .038), being 5-fold higher between 16:00-19:59 h than 08:00-11:59 h. Presentations of both control groups additionally exhibited such difference, with peak numbers between 16:00 and 19:59 h. Fever intensity of cases tended to be greater by 0.58 °F (p > .10) in those attending the PED between 16:00-23:59 h than 00:00-07:59 h. The control group of children solely with fever showed (p < .0001) time-of-day variation in body temperature, with the difference between presentations of highest and lowest temperature, respectively at ∼21:40 and ∼09:40 h, of 0.4 °F.

NOVELTY OF FINDINGS

This is the first study to report time-of-day variation in FS of American children, which is like that reported in children of other countries. The peak number of presentations for FS corresponds in time both with that for fever without seizure and that for any medical emergency, and, additionally, fever intensity of fever controls.

Safety and efficacy of melatonin supplementation as an add-on treatment for infantile epileptic spasms syndrome: A randomized, placebo-controlled, double-blind trial

This was a prospective, randomized, double-blind, single-center placebo-controlled trial to assess the efficacy and safety of melatonin as an add-on treatment for infantile epileptic spasms syndrome (IESS). Participants aged 3 months to 2 years with a primary diagnosis of IESS were recruited and assigned to two groups in a 1:1 ratio. Both treatment groups received a combination of adrenocorticotrophic hormone (ACTH) and magnesium sulfate (MgSO4 ) for 2 weeks, and the treatment group also received melatonin (3 mg) between 20:00 and 21:00 daily, 0.5-1 h before bedtime. The study's primary endpoint was the average reduction rate in spasm frequency assessed by seizure diaries. Secondary endpoints included assessment of the response rate, EEG hypsarrhythmia (Kramer score), and psychomotor development (Denver Developmental Screening Test, DDST). Sleep quality was assessed by using the Brief Infant Sleep Questionnaire (BISQ), the Infant Sleep Assessment Scale (ISAS), and actigraphy. Safety parameters were also evaluated. Statistical analyses were conducted on intention-to-treat and per-protocol populations. The trial is registered at Clinicaltrials.gov (ChiCTR2000036208). Out of 119 screened patients, 70 were randomized and 66 completed treatments. In the intention-to-treat population, there were no significant differences in the average percentage reduction of spasm frequency (median [interquartile range, IQR: Q3-Q1], 100% [46.7%] vs. 66.7% [55.3%], p = .288), the 3-day response rate (51.4% vs. 37.1%, p = .229), the 28-day response rate (42.9% vs. 28.6%, p = .212), EEG Kramer scores (2 [3.5] vs. 2 [3], p = .853), or DDST comprehensive months (5 [2.5] vs. 6 [6], p = .239) between the melatonin (n = 35) and placebo (n = 35) groups. However, caregivers reported improved sleep quality after melatonin treatment, with 85.7% reporting regular sleep compared to 42.9% with placebo (42.9%, p < .001). The melatonin group had lower ISAS scores in 4-11-month-old patients compared to the placebo (mean ± SD, 29.3 ± 4.4 vs. 35.2 ± 5.9, p < .001). Moreover, the median (IQR) value of sleep-onset latency was shortened by 6.0 (24.5) min after melatonin treatment, while that in the placebo group was extended by 3.0 (22.0) min (p = .030). The serum melatonin (6:00 h) level (pg/mL) of the children in the melatonin group after treatment was significantly higher than in the placebo group (median [IQR], 84.8 [142] vs. 17.5 [37.6], p < .001). No adverse effects related to melatonin were observed in the study, and there were no significant differences in adverse effects between the melatonin and placebo groups. Although not statistically significant, the results of this randomized clinical trial proved that melatonin supplementation, as an add-on treatment, can improve spasm control rate in the treatment of IESS. For IESS children treated with ACTH, the addition of melatonin was found to improve sleep quality, shorten sleep onset latency, and increase blood melatonin levels. Moreover, it was observed to be a safe treatment option.

Development of a prediction nomogram model of recurrent febrile seizures in pediatric children

The purpose of this study is to develop a prediction nomogram of recurrent febrile seizures in pediatric children based on the identified predictors for developing recurrent febrile seizures. This is a retrospective observational study. The medical records of 320 febrile seizure-afflicted children admitted to Zhoushan Women and Children Hospital from March 2019 to January 2023 were retrospectively reviewed. Children were divided into the recurrent febrile seizures group and the non-recurrent febrile seizures group. The predictors of recurrent febrile seizures were identified by univariate and multivariate analyses. A prediction nomogram model was developed via R software. The performance of the nomogram was internally validated to assess the model's discrimination and consistency, and decision curve analysis was employed to assess clinical utility. There were 41 out of 320 cases that had recurrent febrile seizures during the observation period, with a 12.81% prevalence rate of recurrent febrile seizures. The predictors of recurrent febrile seizures were young age at the first febrile seizures, a family history of febrile seizures in a first-degree relative, diurnal variation of initial febrile seizures occurrence, gender, and a low level of C-reactive protein. The area under the receiver operating characteristic curve of the nomogram is 0.795 (95% confidence interval: 0.720-0.871). Calibration plots and the result of the Hosmer-Lemeshow test (P = 0.472) reveal satisfactory consistency. Decision curve analysis showed a significant net benefit of the nomogram.

CONCLUSIONS

The prediction nomogram model demonstrates good performance and clinical utility, which would be a convenient tool for the detection of children in pediatrics with high-risk recurrent febrile seizures. It is useful for pediatric medical staff to provide early medical interventions and family counseling.

WHAT IS KNOWN

• A proportion of children experience recurrences of febrile seizures. • Recognition of risk factors for recurrent FS in pediatrics would be useful for the prediction of risk probabilities and help provide tailored counseling and follow-up.

WHAT IS NEW

• A nomogram model is developed for risk prediction of recurrent febrile seizures in this study, which would be a convenient risk prediction tool in pediatrics. • The predictor of diurnal variation of recurrent febrile seizures is with new ideas.

Effects of season, daytime, sex, and stress on the incidence, latency, frequency, severity, and duration of neonatal seizures in a rat model of birth asphyxia

Neonatal seizures are common in newborn infants after birth asphyxia. They occur more frequently in male than female neonates, but it is not known whether sex also affects seizure severity or duration. Furthermore, although stress and diurnal, ultradian, circadian, or multidien cycles are known to affect epileptic seizures in adults, their potential impact on neonatal seizures is not understood. This prompted us to examine the effects of season, daytime, sex, and stress on neonatal seizures in a rat model of birth asphyxia. Seizures monitored in 176 rat pups exposed to asphyxia on 40 experimental days performed over 3 years were evaluated. All rat pups exhibited seizures when exposed to asphyxia at postnatal day 11 (P11), which in terms of cortical development corresponds to term human babies. A first examination of these data indicated a seasonal variation, with the highest seizure severity in the spring. Sex and daytime did not affect seizure characteristics. However, when rat pups were subdivided into animals that were exposed to acute (short-term) stress after asphyxia (restraint and i.p. injection of vehicle) and animals that were not exposed to this stress, the seizures in stress-exposed rats were more severe but less frequent. Acute stress induced an increase in hippocampal microglia density in sham-exposed rat pups, which may have an additive effect on microglia activation induced by asphyxia. When seasonal data were separately analyzed for stress-exposed vs. non-stress-exposed rat pups, no significant seasonal variation was observed. This study illustrates that without a detailed analysis of all factors, the data would have erroneously indicated significant seasonal variability in the severity of neonatal seizures. Instead, the study demonstrates that even mild, short-lasting postnatal stress has a profound effect on asphyxia-induced seizures, most likely by increasing the activity of the hypothalamic-pituitary-adrenal axis. It will be interesting to examine how postnatal stress affects the treatment and adverse outcomes of birth asphyxia and neonatal seizures in the rat model used here.

Effect of melatonin on sleep quality and EEG features in childhood epilepsy: a possible non-conventional treatment

Background

Sleep and epilepsy are characterized by a bidirectional relationship. Indeed, epilepsy predisposes to the development of sleep disorders, while sleep deprivation may exacerbate epilepsy. In addition, antiseizure medication can disrupt normal sleep architecture. Therefore, adequate sleep hygiene could lead to improvement in seizure control. The present study aimed to evaluate the effect of melatonin on seizure frequency, EEG tracing, and sleep in children with focal idiopathic epilepsy.

Methods

This observation study evaluated the effect of 4 mg oral melatonin in ameliorating sleep-wake cycle, seizure frequency, and EEG features in children with focal idiopathic epilepsy of infancy. Twenty children were enrolled from September 2020 to August 2021. The study consisted of serial controls at enrollment (t0), at 3 months (t1), and at 6 months (t2) including neurological examination, questionnaire about sleep disturbances (CSHQ), and EEG.

Results

A significant improvement in sleep quality and daytime sleepiness was observed after melatonin supplementation. Furthermore, we observed a noteworthy improvement in EEG tracing at t2 that exhibited a significant correlation with improvements in CSHQ scores.

Conclusion

The studies conducted so far to evaluate the effect of melatonin in persons with epilepsy do not lead to definitive conclusions. Despite the small population sample and the study design, we report sleep and EEG improvement after melatonin administration in our cohort. Larger studies are needed to further study the neuroprotective and anticonvulsant properties of melatonin.

Serum Levels of Neuropeptides in Epileptic Encephalopathy With Spike-and-Wave Activation in Sleep

BACKGROUND

Epileptic encephalopathy with spike-and-wave activation in sleep (EE-SWAS) is a syndrome of childhood, characterized by diffuse or generalized spike-wave activity in electroencephalography during non-rapid eye movement sleep. Neuropeptides have been demonstrated in several studies to function in the sleep-wake cycle and display convulsant and anticonvulsant features. In this study, we aimed to investigate the relationship between EE-SWAS and neuropeptides such as dynorphin, galanin, ghrelin, leptin, melatonin, and orexin.

METHODS

This multicenter study was conducted from July 2019 to January 2021. There were three groups: Group 1 contained patients with EE-SWAS. Group 2 consisted of patients with self-limited focal epilepsy of childhood (SeLFE), and group 3 was the control group. Levels of neuropeptides were compared in the sera of these three groups.

RESULTS

There were 59 children aged between four and 15 years. Group 1 contained 14 children, group 2 contained 24 children, and group 3 contained 21 children. The level of leptin is higher and the level of melatonin is lower in group 1 than in group 3 (P = 0.01 and P = 0.005, respectively). In group 3, the level of orexin was lower than in both groups 2 and 3 (P = 0.01 and P = 0.01).

CONCLUSIONS

These data show that the level of leptin was higher and the level of melatonin was lower in patients with EE-SWAS than in the control group. Furthermore, patients with EE-SWAS had lower orexin levels than both the control group and patients with SeLFE. Further research is required to understand the potential role of these neuropeptides in the pathophysiology of EE-SWAS.

Melatonin supplementation for the treatment of infantile spasms: protocol for a randomised placebo-controlled triple-blind trial

INTRODUCTION

Infantile spasms (IS) is a type of severe epileptic encephalopathy that occurs in infancy and early childhood. IS is characterised clinically by epileptic spasms, often accompanied by sleep disorder and abnormal circadian rhythm. The endogenous circadian rhythm disorder, in turn, can make spasms worse. Melatonin has also been found to have anticonvulsant and neuroprotective properties by adjusting the circadian rhythm. However, there are lack of relevant studies on controlling IS by using melatonin. This study aims to analyse the therapeutic effect of melatonin supplementation for the treatment of IS.

METHODS AND ANALYSIS

This is a triple-blinded (trial participant, outcome assessor and the data analyst), prospective, randomised controlled trial to be conducted in the Department of Paediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China from November 2020. Patients (n=70) aged 3 months to 2 years with IS will be recruited in this study after receiving written consent from their parents or guardians. Patients will be randomly divided into two equal groups and treated with a combination of adrenocorticotropic hormone, magnesium sulfate and either melatonin or placebo. Clinical data from the patients in the two groups before and after the treatment will be collected and compared. The primary outcome will be assessed 2 weeks later by seizure diaries and reported as the average reduced rate of spasms frequency. Secondary outcomes include the response rate (the rate of spasms-free), electroencephalogram hypsarrhythmia assessment and the psychomotor development assessment (Denver Developmental Screening Test). Sleep quality and safety will also be assessed.

ETHICS AND DISSEMINATION

The protocol for this study was approved by the Ethics Committee of Chinese PLA General Hospital (reference number S2020-337-01) and was reported according to the Standard Protocol Items: Recommendations for Interventional Trials statement. Findings of this research will be disseminated through national and international meetings, conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2000036208.

Melatonin's Benefits and Risks as a Therapy for Sleep Disturbances in the Elderly: Current Insights

Aging is accompanied by circadian changes, including disruptive alterations in the sleep/wake cycle, as well as the beginning of low-degree inflammation ("inflammaging"), a scenario that leads to several chronic illnesses, including cancer, and metabolic, cardiovascular, and neurological dysfunctions. As a result, any effective approach to healthy aging must consider both the correction of circadian disturbance and the control of low-grade inflammation. One of the most important prerequisites for healthy aging is the preservation of robust circadian rhythmicity (particularly of the sleep/wake cycle). Sleep disturbance disrupts various activities in the central nervous system, including waste molecule elimination. Melatonin is a chemical with extraordinary phylogenetic conservation found in all known aerobic creatures whose alteration plays an important role in sleep changes with aging. Every day, the late afternoon/nocturnal surge in pineal melatonin helps to synchronize both the central circadian pacemaker found in the hypothalamic suprachiasmatic nuclei (SCN) and a plethora of peripheral cellular circadian clocks. Melatonin is an example of an endogenous chronobiotic substance that can influence the timing and amplitude of circadian rhythms. Moreover, melatonin is also an excellent anti-inflammatory agent, buffering free radicals, down-regulating proinflammatory cytokines, and reducing insulin resistance, among other things. We present both scientific and clinical evidence that melatonin is a safe drug for treating sleep disturbances in the elderly.

Associations between Melatonin, Neuroinflammation, and Brain Alterations in Depression

Pro-inflammatory systemic conditions that can cause neuroinflammation and subsequent alterations in brain regions involved in emotional regulation have been suggested as an underlying mechanism for the pathophysiology of major depressive disorder (MDD). A prominent feature of MDD is disruption of circadian rhythms, of which melatonin is considered a key moderator, and alterations in the melatonin system have been implicated in MDD. Melatonin is involved in immune system regulation and has been shown to possess anti-inflammatory properties in inflammatory conditions, through both immunological and non-immunological actions. Melatonin has been suggested as a highly cytoprotective and neuroprotective substance and shown to stimulate all stages of neuroplasticity in animal models. The ability of melatonin to suppress inflammatory responses through immunological and non-immunological actions, thus influencing neuroinflammation and neurotoxicity, along with subsequent alterations in brain regions that are implicated in depression, can be demonstrated by the antidepressant-like effects of melatonin. Further studies that investigate the associations between melatonin, immune markers, and alterations in the brain structure and function in patients with depression could identify potential MDD biomarkers.

Protective Effect of Melatonin Administration against SARS-CoV-2 Infection: A Systematic Review

Introduction: according to the World Health Organization (WHO), COVID-19 is an infectious disease caused by the SARS-CoV-2 virus, responsible for an increasing number of cases and deaths. From a preventive and therapeutic point of view, there are two concerns that affect institutions and healthcare professionals: global immunization (which is still far from being achieved) and the availability of drugs capable of preventing its consequences in the infected patient. In this sense, the role that melatonin can play is has been assessed in the recent literature. Justification and Objectives: the serious health, social and economic consequences of COVID-19 have forced an urgent search for preventive methods, such as vaccines, among others, and therapeutic methods that could be alternatives to the drugs currently used. In this sense, it must be accepted that one of the most recommended has been the administration of melatonin. The present study proposes to carry out a systematic review of its possible role in the treatment and/or prevention of COVID-19. Material and methods: a systematic review of the literature related to the prevention of COVID-19 through the administration of melatonin was carried out, following the sequence proposed by the Prisma Declaration regarding the identification and selection of documents, using the specialized health databases Trip Medical Database, Cochrane Library, PubMed, Medline Plus, BVS, Cuiden and generic databases such as Dialnet, Web of Science and Google Scholar for their retrieval. Appropriate inclusion and exclusion criteria are described for the articles assessed. The main limitation of the study has been the scarcity of works and the lack of defining a specific protocol in terms of dosage and administration schedule. Results: once the selection process was completed, and after an in-depth critical analysis, 197 papers were selected, and 40 of them were finally used. The most relevant results were: (1) melatonin prevents SARS-CoV-2 infection, (2) although much remains to be clarified, at high doses, it seems to have a coadjuvant therapeutic effect in the treatment of SARS-CoV-2 infection and (3) melatonin is effective against SARS-CoV-2 infection. Discussion: until group immunization is achieved in the population, it seems clear that we must continue to treat patients with SARS-CoV-2 infection, and, in the absence of a specific and effective antiviral therapy, it is advisable to continue researching and providing drugs that demonstrate validity based on the scientific evidence. In this regard, we believe that the available studies recommend the administration of melatonin for its anti-inflammatory, antioxidant, immunomodulatory, sleep-inducing, CD147, Mpro, p65 and MMP9 protein suppressing, nephrotoxicity-reducing and highly effective and safe effects. Conclusions: (1) melatonin has anti-inflammatory, antioxidant, immunomodulatory, and Mpro and MMP9 protein-inhibitory activity. (2) It has been shown to have a wide margin of safety. (3) The contributions reviewed make it an effective therapeutic alternative in the treatment of SARS-CoV-2 infection. (4) Further clinical trials are recommended to clearly define the administration protocol.

Melatonin salvages lead-induced neuro-cognitive shutdown, anxiety, and depressive-like symptoms via oxido-inflammatory and cholinergic mechanisms

INTRODUCTION

Lead is the most used nonphysiological neurotoxic heavy metal in the world that has been indicated to interfere with the cognitive and noncognitive processes via numerous mechanisms. The neuroprotective effect of melatonin is well known, but the effect of its interaction with lead in the brain remains inconclusive.

OBJECTIVE

To assess the therapeutic role of melatonin on cognitive deficit, anxiety and depressive-like symptoms in matured male Wistar rats exposed to a subchronic lead chloride (PbCl₂ ).

METHODS

Twenty male Wistar rats were blindly randomized into four groups (n = 5/group): group 1 to 4 underwent intragastric administration of physiological saline (10 ml/kg; vehicle), PbCl₂ (50 mg/kg), melatonin (10 mg/kg) and PbCl₂ + melatonin respectively for a period of 4 weeks during which neurobehavioral data were extracted, followed by neurochemical and histopathological evaluations.

RESULTS

Exposure to PbCl₂ reduced cognitive performance by increasing the escape latency and average proximity to the platform zone border, decreasing average path length in the platform zone, cognitive score, and time spent in probing. It raised the thigmotaxis percentage, time spent in rearing, number of pellet-like feces, and time spent in the dark compartment of a bright/dark box which are predictors of anxiety. It also induced depressive-like behavior as immobility time was enhanced. PbCl₂ deranged neurochemicals; malondialdehyde, interlukin-1β, and tumor necrotic factor-α were increased while superoxide dismutase and acetylcholinesterase were decreased without remarkable alteration in reduced glutathione and nitric oxide. Administration of PbCl₂ further disrupted neuronal settings of hippocampal proper and dentate gyrus. In contrast, the supplementation of melatonin reversed all the neurological consequences of PbCl₂ neurotoxicity by eliciting its properties against oxidative and nonoxidative action of PbCl₂ .

CONCLUSION

These findings suggest that melatonin down-regulates neurotoxicant interplays in the brain systems. Therefore, this study suggests the use of melatonin as an adjuvant therapy in neuropathological disorders/dysfunctions.

Melatonin for the Management of Preeclampsia: A Review

Preeclampsia is a disease specific to pregnancy characterised by new-onset hypertension with maternal organ dysfunction and/or fetal growth restriction. It remains a major cause of maternal and perinatal morbidity and mortality. For sixty years, antihypertensives have been the mainstay of treating preeclampsia and only recently have insights into the pathogenesis of the disease opened new avenues for novel therapies. Melatonin is one such option, an endogenous and safe antioxidant, that may improve the maternal condition in preeclampsia while protecting the fetus from a hostile intrauterine environment. Here we review the evidence for melatonin as a possible adjuvant therapy for preeclampsia, including in vitro evidence supporting a role for melatonin in protecting the human placenta, preclinical models, vascular studies, and clinical studies in hypertension and pregnancy.

Hypothermia Plus Melatonin in Asphyctic Newborns: A Randomized-Controlled Pilot Study

OBJECTIVES

To investigate the effect of adding melatonin to hypothermia treatment on neurodevelopmental outcomes in asphyctic newborns.

DESIGN

Pilot multicenter, randomized, controlled, double-blind clinical trial. Statistical comparison of results obtained in two intervention arms: hypothermia plus placebo and hypothermia plus melatonin.

SETTING

Level 3 neonatal ICU.

PATIENTS

Twenty-five newborns were recruited.

INTERVENTIONS

The hypothermia plus melatonin patients received a daily dose of IV melatonin, 5 mg per kg body weight, for 3 days. General laboratory variables were measured both at neonatal ICU admission and after intervention. All infants were studied with amplitude-integrated electroencephalography and brain MRI within the first week of life. The neurodevelopmental Bayley III test, the Gross Motor Function Classification System, and the Tardieu scale were applied at the ages of 6 and 18 months.

MEASUREMENTS AND MAIN RESULTS

Clinical characteristics, laboratory evaluations, MRI findings, and amplitude-integrated electroencephalography background did not differ between the treatment groups. The newborns in the hypothermia plus melatonin group achieved a significantly higher composite score for the cognitive section of the Bayley III test at 18 months old, with respect to the hypothermia plus placebo group (p = 0.05). There were no differences between the groups according to the Gross Motor Function Classification System and Tardieu motor assessment scales.

CONCLUSIONS

The early addition of IV melatonin to asphyctic neonates is feasible and may improve long-term neurodevelopment. To our knowledge, this is the first clinical trial to analyze the administration of IV melatonin as an adjuvant therapy to therapeutic hypothermia.

Neuromodulation of the Pineal Gland via Electrical Stimulation of Its Sympathetic Innervation Pathway

Stimulation of the pineal gland via its sympathetic innervation pathway results in the production of N-acetylserotonin and melatonin. Melatonin has many therapeutic roles and is heavily implicated in the regulation of the sleep-wake cycle. In addition, N-acetylserotonin has recently been reported to promote neurogenesis in the brain. Upregulation of these indoleamines is possible via neuromodulation of the pineal gland. This is achieved by electrical stimulation of structures or fibres in the pineal gland sympathetic innervation pathway. Many studies have performed such pineal neuromodulation using both invasive and non-invasive methods. However, the effects of various experimental variables and stimulation paradigms has not yet been reviewed and evaluated. This review summarises these studies and presents the optimal experimental protocols and stimulation parameters necessary for maximal upregulation of melatonin metabolic output.

Levels of Melatonin in Continuous Spikes and Waves During Sleep

Levels of melatonin have been reported before in children with epilepsy, but such has not been reported to date in those with continuous spikes and waves during sleep. The aim of the present study was to assess serum melatonin levels and melatonin circadian rhythm in patients with continuous spikes and waves during sleep and epilepsy. Serum melatonin was measured in 39 children stratified into 3 groups. Group 1 included 15 patients with continuous spikes and waves during sleep, group 2 included 12 epilepsy patients, and group 3 included 12 controls, respectively. Blood samples were taken from all participants at 1:00 am and 9:00 am and melatonin levels were measured using a quantitative enzyme-linked immunosorbent assay test. The 9:00 am melatonin levels of group 1 were significantly decreased and pair groups were compared. The P_a value (representing a comparison between groups 1 and 2) was .002, the P_b value (representing a comparison between groups 1 and 3) was .001, and the P_c value (representing a comparison between groups 2 and 3) was .86. These findings suggest that the 9:00 am melatonin levels were significantly decreased in the comparison of groups 2 and 3. Further detailed research is necessary to determine the factors leading to the rapid decline of morning melatonin levels of children with continuous spikes and waves during sleep.

Serum Melatonin Values in Normal Dogs and Dogs with Seizures

Epilepsy, or recurrent seizures, is reported to be the most common neurologic condition in dogs; 20–30% of epileptic dogs are considered to be pharmacoresistent to one medication. The hormone melatonin has been shown to have significant anticonvulsant effects; epileptic humans have lower serum melatonin levels than unaffected individuals. We hypothesize that serum levels of melatonin will be lower in dogs with seizures as compared with normal dogs. Sixty-two dogs were enrolled in the study: 29 normal dogs (Group 1) and 33 dogs with seizures (Group 2). Blood sampling was done at three separate time points (8:00 a.m., 12:00, and 4:00 p.m.). The majority of dogs in Groups 1 (69%) and 2 (76%) had serum melatonin levels &lt;0.5 pg/mL as measured by radioimmunoassay. There were no significant differences in serum melatonin values between the groups or within groups when time of blood draw, length of sample freezing, time of day/year of sampling, or presence of anticonvulsant therapy were compared. There were no notable differences in daytime serum melatonin values in normal dogs versus dogs with seizures. The majority of daytime serum melatonin levels were &lt;0.5 pg/mL in dogs with and without seizures.

Analysis of Different Melatonin Secretion Patterns in Children With Sleep Disorders: Melatonin Secretion Patterns in Children

The objective of this study was to analyze circadian patterns of urinary 6-sulphatoxymelatonin (aMT6s) excretion in children with primary sleep disorders in comparison with healthy controls. A total of 124 control children and 124 patients (aged 4-14 years) diagnosed with diverse primary sleep disorders were recruited. aMT6s concentrations were measured in diurnal and nocturnal urine, as well as in 24-hour urine. aMT6s levels were significantly higher and showed significantly more evident circadian variations in the control group ( P < .001). Four different melatonin (aMT) production and excretion patterns were distinguished in the group with sleep disorders: (1) standard aMT production pattern, (2) low aMT production pattern, (3) aMT production pattern with absence of circadian variation, and (4) aMT hyperproduction pattern. This study highlights the importance of analyzing specific alterations of aMT secretion in each sleep disorder and provides evidences to explain why not all children with sleep disturbances do respond to aMT treatment.

Effects of agomelatine on pentylenetetrazole-induced kindling, kindling-associated oxidative stress, and behavioral despair in mice and modulation of its actions by luzindole and 1-(m-chlorophenyl) piperazine

In view of well-evidenced antiepileptic effects of melatonin and few reports of anticonvulsant action of agomelatine, the present study investigated whether agomelatine protects against pentylenetetrazole (PTZ)-induced kindling in mice and kindling-associated oxidative stress, depression, and impairment of spatial memory. In order to explore whether effects are mediated by melatonergic or serotonergic mechanisms, 1-(m-chlorophenyl) piperazine (mCPP), selective 5HT2c receptor agonist and luzindole, melatonergic receptor antagonist, were taken as pharmacological tools. In view of few hepatotoxic reports on agomelatine, the study evaluated effects on hepatic enzyme levels. Swiss strain albino mice were injected with PTZ (25mg/kg, i.p.) once every two days for 5weeks to induce kindling. The effects of agomelatine (10mg/kg, p.o.) alone and in combination with luzindole (2.5mg/kg, i.p.) or mCPP (7mg/kg, i.p.) on seizure severity during induction and % incidence of animals kindled at the end of 5weeks were recorded. Modified forced swim test was used for studying depression-like behavior while spontaneous alternation behavior was used for studying effects on spatial memory. Serum AST and ALT concentrations, cortical and hippocampal malondialdehyde, and reduced glutathione were measured. Agomelatine 10mg/kg, p.o. effectively delayed development of kindling, reduced seizure severity, and decreased % incidence. Luzindole reversed the protective effects of agomelatine while mCPP failed to show such a reversal, indicating melatonergic (and not serotonergic) mechanisms in the observed effects. Agomelatine also showed antioxidant effects that can partially contribute to its anticonvulsant action. In addition, it alleviated PTZ-kindling-associated behavioral despair and favorably modulated liver enzymes. Its effects on improvement of kindling-associated spatial memory could possibly be related to its effects on locomotor activity. Agomelatine, thus, could be explored as an adjunct to antiepileptic drugs for seizure control and for alleviating epilepsy-associated depression.

Melatonin in Critically Ill Children

Melatonin, while best known for its chronobiologic functions, has multiple effects that may be relevant in critical illness. It has been used for circadian rhythm maintenance, analgesia, and sedation, and has antihypertensive, anti-inflammatory, antioxidant, antiapoptotic, and antiexcitatory effects. This review examines melatonin physiology in health, the current state of knowledge regarding endogenous melatonin production in pediatric critical illness, and the potential uses of exogenous melatonin in this population, including relevant information from basic sciences and other fields of medicine. Pineal melatonin production and secretion appears to be altered in critical illness, though understanding in pediatric critical illness is in early stages, with only 102 children reported in the current literature. Exogenous melatonin may be used for circadian rhythm disturbances and, within the critically ill population, holds promise for diseases involving oxidant stress. There are no studies of exogenous melatonin administration to critically ill children beyond the neonatal period.

Melatonin as add-on treatment for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 6, 2012.Epilepsy is one of the most common chronic neurological disorders. Despite the plethora of antiepileptic drugs (AEDs) currently available, 30% of people continue having seizures. This group of people requires a more aggressive treatment, since monotherapy, the first choice scheme, fails to control seizures. Nevertheless, polytherapy often results in a number of unwanted effects, including neurological disturbances (somnolence, ataxia, dizziness), psychiatric and behavioural symptoms, and metabolic alteration (osteoporosis, inducement or inhibition of hepatic enzymes, etc.). The need for better tolerated AEDs is even more urgent in this group of people. Reports have suggested an antiepileptic role of melatonin with a good safety profile.

OBJECTIVES

To assess the efficacy and tolerability of melatonin as add-on treatment for epilepsy.

SEARCH METHODS

For the latest update, we searched the Cochrane Epilepsy Group's Specialized Register (12 January 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 12 January 2016), and MEDLINE (Ovid, 11 January 2016). We searched the bibliographies of any identified study for further references. We handsearched selected journals and conference proceedings. We applied no language restrictions. In addition, we contacted melatonin manufacturers (i.e. Nathura) and original investigators to identify any unpublished studies.

SELECTION CRITERIA

Randomized controlled trials; double, single, or unblinded trials; parallel group or cross-over studies. People with epilepsy regardless of age and gender, including children and adults with disabilities. Administration of melatonin as add-on treatment to any AED(s) compared to add-on placebo or no add-on treatment.

DATA COLLECTION AND ANALYSIS

Review authors independently selected trials for inclusion according to pre-defined criteria, extracted relevant data, and evaluated the methodological quality of trials. We assessed the following outcomes: at least 50% seizure reduction, seizure freedom, adverse events, and quality of life.

MAIN RESULTS

We included six publications, with 125 participants (106 aged under 18 years). Two different comparisons were available: melatonin versus placebo and melatonin 5 mg versus melatonin 10 mg. Despite our primary intention, due to insufficient information on outcomes, we were unable to perform any meta-analyses, but summarized data narratively. Four studies were randomized, double-blind, cross-over, placebo-controlled trials and two were randomized, double-blind, parallel, placebo-controlled trials. Only two studies provided the exact number of seizures during the trial compared to the baseline: none of the participants with seizures during the trial had a change in seizure frequency compared with the baseline. Two studies systematically evaluated adverse effects (worsening of headache was reported in a child with migraine under melatonin treatment). Only one study systematically evaluated quality of life, showing no statistically significant improvement in quality of life in the add-on melatonin group.

AUTHORS' CONCLUSIONS

Included studies were of poor methodological quality, and did not systematically evaluate seizure frequency and adverse events, so that it was impossible to summarize data in a meta-analysis. It is not possible to draw any conclusion about the role of melatonin in reducing seizure frequency or improving quality of life in people with epilepsy.

Evaluation of Plasma Melatonin Levels in Children With Afebrile and Febrile Seizures

BACKGROUND

Melatonin modulates central nervous system neuronal activity. We compared the melatonin levels of patients with febrile and afebrile seizures during and after seizure with those of healthy controls.

METHODS

We enrolled 59 individuals with afebrile and febrile seizures (mean age, 6.09 ± 4.46 years) and 28 age-, sex-, and weight-matched healthy children. Melatonin levels were measured near the time of a seizure (0 to 1 hour) and at 12 and 24 hours post-seizure, and control melatonin levels were measured from a single venous blood sample.

RESULTS

Plasma melatonin levels increased during seizures in the study group (P < 0.001). Post-seizure plasma melatonin levels were significantly lower in the study group than in the control group (P < 0.05). Plasma melatonin levels did not differ between patients with afebrile seizures who had and had not used antiepileptic drugs. Daytime (8 AM to 8 PM) and nighttime (8 PM to 8 AM) post-seizure melatonin levels were not significantly different.

CONCLUSIONS

Melatonin levels were lower in pediatric patients prone to seizures than in healthy children and increased during seizures. Further research is needed to test the role of melatonin in the pathophysiology and treatment of epilepsy.

Melatonin as add-on treatment for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 6, 2012.Epilepsy is one of the most common chronic neurological disorders. Despite the plethora of antiepileptic drugs (AEDs) currently available, 30% of people continue having seizures. This group of people requires a more aggressive treatment, since monotherapy, the first choice scheme, fails to control seizures. Nevertheless, polytherapy often results in a number of unwanted effects, including neurological disturbances (somnolence, ataxia, dizziness), psychiatric and behavioural symptoms, and metabolic alteration (osteoporosis, inducement or inhibition of hepatic enzymes, etc.). The need for better tolerated AEDs is even more urgent in this group of people. Reports have suggested an antiepileptic role of melatonin with a good safety profile.

OBJECTIVES

To assess the efficacy and tolerability of melatonin as add-on treatment for epilepsy.

SEARCH METHODS

For the latest update, we searched the Cochrane Epilepsy Group's Specialized Register (12 January 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 12 January 2016), and MEDLINE (Ovid, 11 January 2016). We searched the bibliographies of any identified study for further references. We handsearched selected journals and conference proceedings. We applied no language restrictions. In addition, we contacted melatonin manufacturers (i.e. Nathura) and original investigators to identify any unpublished studies.

SELECTION CRITERIA

Randomized controlled trials; double, single, or unblinded trials; parallel group or cross-over studies. People with epilepsy regardless of age and gender, including children and adults with disabilities. Administration of melatonin as add-on treatment to any AED(s) compared to add-on placebo or no add-on treatment.

DATA COLLECTION AND ANALYSIS

Review authors independently selected trials for inclusion according to pre-defined criteria, extracted relevant data, and evaluated the methodological quality of trials. We assessed the following outcomes: at least 50% seizure reduction, seizure freedom, adverse events, and quality of life.

MAIN RESULTS

We included six publications, with 125 participants (106 aged under 18 years). Two different comparisons were available: melatonin versus placebo and melatonin 5 mg versus melatonin 10 mg. Despite our primary intention, due to insufficient information on outcomes, we were unable to perform any meta-analyses, but summarized data narratively. Four studies were randomized, double-blind, cross-over, placebo-controlled trials and two were randomized, double-blind, parallel, placebo-controlled trials. Only two studies provided the exact number of seizures during the trial compared to the baseline: none of the participants with seizures during the trial had a change in seizure frequency compared with the baseline. Two studies systematically evaluated adverse effects (worsening of headache was reported in a child with migraine under melatonin treatment). Only one study systematically evaluated quality of life, showing no statistically significant improvement in quality of life in the add-on melatonin group.

AUTHORS' CONCLUSIONS

Included studies were of poor methodological quality, and did not systematically evaluate seizure frequency and adverse events, so that it was impossible to summarize data in a meta-analysis. It is not possible to draw any conclusion about the role of melatonin in reducing seizure frequency or improving quality of life in people with epilepsy.

Diurnal and seasonal occurrence of febrile seizures

BACKGROUND

Febrile seizures are the most common seizures in children, but their pathogenesis remains unknown. Some studies have suggested an association between the light-dependent secretion of melatonin and the occurrence of febrile seizures. The diurnal and seasonal occurrence of febrile seizures could clarify the role daylight plays in febrile seizures.

METHODS

In Finland, summer days are long and bright and winter days are short and dark. We evaluated the diurnal and seasonal occurrence of the first febrile seizures in 461 children and adjusted them according to the epidemiology of the febrile episodes in a population-based study of 1522 children.

RESULTS

The first febrile seizure most often occurred in the evening, peaking between 6 and 10 PM (31%), and least often at night, in the early morning hours between 2 and 6 AM (8%) (P < 0.001). This diurnal pattern repeated itself in different seasons according to variance in daylight duration. Febrile seizures occurred irregularly throughout the year, most frequently in winter, concurrently with the febrile episodes, and least frequently in summer; this seasonal variation in the occurrence of febrile seizures disappeared however when adjusted for the number of febrile events.

CONCLUSIONS

We found clear diurnal and seasonal variations in the occurrence of febrile seizures, even though they did not follow the amount of daylight. Our findings do not support the hypothesis that the diurnal and seasonal variation of daylight explains the occurrence of febrile seizures. Moreover, febrile events associated strongly with the occurrence of febrile seizures.

Analgesic, anxiolytic and anaesthetic effects of melatonin: new potential uses in pediatrics

Exogenous melatonin is used in a number of situations, first and foremost in the treatment of sleep disorders and jet leg. However, the hypnotic, antinociceptive, and anticonvulsant properties of melatonin endow this neurohormone with the profile of a drug that modulates effects of anesthetic agents, supporting its potential use at different stages during anesthetic procedures, in both adults and children. In light of these properties, melatonin has been administered to children undergoing diagnostic procedures requiring sedation or general anesthesia, such as magnetic resonance imaging, auditory brainstem response tests and electroencephalogram. Controversial data support the use of melatonin as anxiolytic and antinociceptive agents in pediatric patients undergoing surgery. The aim of this review was to evaluate available evidence relating to efficacy and safety of melatonin as an analgesic and as a sedative agent in children. Melatonin and its analogs may have a role in antinociceptive therapies and as an alternative to midazolam in premedication of adults and children, although its effectiveness is still controversial and available data are clearly incomplete.

Oxidative stress induced by epileptic seizure and its attenuation by melatonin

An epileptic seizure and postictal period in addition to well-known features are also characterized by massive consumption of energy. This is thought to lead to oxidative stress and increased generation of free radicals, which is reflected by increased levels of oxidative products. Our previous work described the neuroprotective effects of melatonin in preventing cognitive worsening after a single epileptic seizure. This work was aimed on direct measurement of free radicals in brain tissue using the EPR method 1, 15 and 60 minutes after seizure. The measurement was performed in adult male Wistar rats at the mentioned intervals after a single tonic-clonic seizure induced by flurothyl. In comparison to control animals there was a significant increase in hydroxyl and nitroxyl radicals 60 minutes after the seizure. The levels of hydroxyl radicals were significantly lower in animals that received melatonin 60 minutes before seizure induction compared to animals without preventive treatment. Therefore, melatonin affected the generation of the measured free radicals differently. An important finding was the delayed increase in free radicals after a single seizure in the later phases of recovery.

Circadian profile of salivary melatonin secretion and its concentration after epileptic seizure in patients with drug-resistant epilepsy--preliminary report

BACKGROUND

The results of a few previous studies assessing melatonin concentration in epileptic patient are ambiguous. This study aimed at: (1) comparing the circadian profile of salivary melatonin excretion in epileptic patients with that in healthy subjects and with circadian frequency profile of seizures and (2) assessing the effect of epileptic seizure upon salivary melatonin concentration.

METHODS

The study included thirty patients suffering from drug-resistant epilepsy aged from 22 to 45 years (mean age 37.17, SD ± 10.25). All subjects had their saliva taken in order to determine melatonin concentration and its circadian excretion profile performed every 4h. Additionally, saliva samples were collected in order to assess concentration of melatonin directly after epileptic seizure and 2h later.

RESULTS

The circadian profile of melatonin secretion in epileptic patients did not differ significantly from a profile in healthy subjects. Epileptic women showed statistically higher average salivary melatonin concentration at 2a.m., 6a.m. and 10a.m., compared to epileptic men; this may be related to lower age average of women as well as to their different hormonal profile.

CONCLUSION

The significantly higher salivary melatonin concentration at 6a.m. in patients with diurnal seizures (occurring mainly in the morning) may suggest proconvulsive effect of this hormone. Epileptic seizure did not lead to significantly elevated salivary melatonin concentration. Epileptogenic effect of melatonin might be corroborated by significantly elevated salivary melatonin levels directly after nocturnal tonic-clonic seizure which affected patients with highest concentration of this hormone at 2a.m. These observations would need confirmation based on studies of larger groups of epileptic patients.

Sleep disorders in children with developmental delay

Developmental disorders in children are common. Associated demanding co-morbidities that include sleep problems are prevalent in this group. In turn, these are linked to daytime performance issues, reduced developmental and academic growth, and considerable familial psychopathology. Behavioral modification measures are and should be the first line approach to management. Medications for sleep disorders have an important role in addition to behavioral modification therapy. This literature review looks into the occurrence and severity of sleep problems in children with developmental disorders. The probable advantages of using medications, mainly focusing on the neurohormone melatonin (a sleep inducer), are also explored.

Does melatonin affect epileptic seizures?

Melatonin is widely used for sleep disorders in patients with a range of developmental disorders and neurodisabilities, who also frequently have epilepsy. The aim of our review was to examine published data to assess the evidence for melatonin affecting seizure control. The literature search revealed 26 papers apparently reporting an association between melatonin and epilepsy or seizures but seven of these did not provide relevant information. Of the three double-blind, randomised, controlled trials, two showed no overall worsening or improvement in seizures, and one recent trial reported a statistically significant reduction in seizures. The open studies reported conflicting results. The few studies on the effect of seizures on melatonin levels have reported that baseline melatonin levels may be low in patients with uncontrolled epilepsy and that levels increase markedly following seizures. The striking finding of this review is the paucity of relevant data from the remarkably small number of studies. These results allow no firm conclusions to be drawn, although it would seem reasonable to observe that there was no marked overall effect on seizures, neither improvement nor worsening. There is a need for large, well designed, randomised, double-blind, placebo-controlled trials to establish the role of melatonin in either predisposing to or decreasing the likelihood of seizures.

Effect of melatonin on seizure frequency in intractable epilepsy: a pilot study

Melatonin is effective for treating sleep-wake cycle disturbances and has been reported occasionally to decrease epileptic seizure frequency, with no long-term side effects. In this pilot study, the investigators examined the effect of melatonin on seizures, sleep quality, and behavior in 10 patients aged 9 to 32 years with intractable epilepsy. Patients were randomized to receive melatonin (10 mg daily at bedtime) followed by placebo or placebo followed by melatonin for 3 weeks each, with a 1-week washout period in between. Seizure frequency was monitored by daily diaries and actigraphy recordings; behavioral and sleep parameters were rated by caregivers. Diurnal seizures decreased significantly with melatonin compared with placebo (P = .034, Wilcoxon test). Maximal number of seizures, seizure duration, sleep efficiency or latency, and behavioral parameters remained unchanged. No major side effects or seizure aggravation were documented. It is concluded that melatonin could be effective and safe for decreasing daytime seizure frequency in patients with intractable epilepsy.

Agomelatine: Its Role in the Management of Major Depressive Disorder

Circadian rhythm abnormalities, as shown by sleep/wake cycle disturbances, constitute one the most prevalent signs of depressive illness; advances or delays in the circadian phase are documented in patients with major depressive disorder (MDD), bipolar disorder, and seasonal affective disorder (SAD). The disturbances in the amplitude and phase of rhythm in melatonin secretion that occur in patients with depression resemble those seen in chronobiological disorders, thus suggesting a link between disturbed melatonin secretion and depressed mood. Based on this, agomelatine, the first MT1/MT2 melatonergic agonist displaying also 5-HT2C serotonergic antagonism, has been introduced as an antidepressant. Agomelatine has been shown to be effective in several animal models of depression and anxiety and it has beneficial effects in patients with MDD, bipolar disorder, or SAD. Among agomelatine's characteristics are a rapid onset of action and a pronounced effectiveness for correcting circadian rhythm abnormalities and improving the sleep/wake cycle. Agomelatine also improves the 3 functional dimensions of depression—emotional, cognitive, and social—thus aiding in the full recovery of patients to a normal life.

Melatonin as add-on treatment for epilepsy

BACKGROUND

Epilepsy is one of the most common chronic neurologic disorders. Despite the plethora of antiepileptic drugs (AEDs) currently available, 30% of patients continue having seizures. This group of patients requires a more aggressive treatment, since monotherapy, the first choice scheme, fails to control seizures. Nevertheless, polytherapy often results in a number of unwanted effects, including neurologic disturbances (somnolence, ataxia, dizziness), psychiatric and behavioral symptoms, and metabolic alteration (osteoporosis, inducement or inhibition of hepatic enzymes, etc.). The need for better tolerated AEDs is even more urgent in this group of patients. Reports have suggested an antiepileptic role of melatonin with a good safety profile.

OBJECTIVES

To assess the efficacy and tolerability of melatonin as add-on treatment for epilepsy.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (May 2012), the Cochrane Central Register of Controlled Trials (CENTRAL Issue 4 of 12, The Cochrane Library 2012), and MEDLINE (1946 to April 2012). The bibliographies of any identified study were searched for further references. We handsearched selected journals and conference proceedings. No language restrictions were imposed. In addition, we contacted melatonin manufacturers (i.e. Nathura) and original investigators to identify any unpublished study.

SELECTION CRITERIA

Randomized controlled trials; double, single, or unblinded trials; parallel group or cross-over studies. People with epilepsy regardless of age and sex, including children and adults with disabilities. Administration of melatonin as add-on treatment to any AED(s) compared to add-on placebo or no add-on treatment.

DATA COLLECTION AND ANALYSIS

Review authors independently selected trials for inclusion according to predefined criteria, extracted relevant data, and evaluated the methodologic quality of trials. The following outcomes were assessed: at least 50% seizure reduction, seizure freedom, adverse events, and quality of life.

MAIN RESULTS

Four publications, with a total of 102 participants (90 aged under 18 years), were included. Two different comparisons were available: 1. melatonin versus placebo and 2. melatonin 5 mg versus melatonin 10 mg. Despite our primary intention, due to insufficient information on outcomes, we were unable to perform any meta-analysis, but summarized data narratively. Two studies were randomized, double-blind, cross-over, placebo-controlled trials and two were randomized, double-blind, parallel, placebo-controlled trials. Only one study provided the exact number of seizures during the trial compared to the baseline: none of the patients with seizures during the trial had a change in seizure frequency compared with the baseline. Adverse events were systematically evaluated in only one study (no adverse events observed). Only one study systematically evaluated quality of life, showing no statistically significant improvement in quality of life in the add-on melatonin group.

AUTHORS' CONCLUSIONS

Included studies were of poor methodologic quality, and did not systematically evaluate seizure frequency and adverse events, so that it was impossible to summarize data in a meta-analysis. It is not possible to draw any conclusion about the role of melatonin in reducing seizure frequency or improving quality of life in patients with epilepsy.

The interaction of melatonin and agmatine on pentylenetetrazole-induced seizure threshold in mice

Melatonin, the major hormone produced by the pineal gland, has a number of functions in mammals, for example, its function as an anticonvulsant. Agmatine, a biogenic amine formed by decarboxylation of L-arginine by arginine decarboxylase, also has anticonvulsant effects. This study investigated the effect of the interaction of melatonin and agmatine on seizure susceptibility in the mouse model of pentylenetetrazole (PTZ)-induced clonic seizures. Further, the researchers investigated the involvement of melatonin receptors in this interaction using luzindole, a ML(1/2) receptor antagonist and prazosin, a ML(3) receptor antagonist. Melatonin, at 40 and 80 mg/kg, and agmatine, at 10 and 20mg/kg, exerted anticonvulsant effects. Luzindole, at 1.25 and 2.5mg/kg, or prazosin, at 0.5mg/kg, did not change the seizure threshold as compared with that of vehicle-treated mice. The anticonvulsant effect of melatonin (40 and 80 mg/kg) was prevented by luzindole (2.5mg/kg) (P<0.001) but not prazosin (0.5mg/kg), indicating the possible involvement of ML(1/2) receptors in the anticonvulsant effect of melatonin. Agmatine (5mg/kg) significantly increased the anticonvulsant effect of both the noneffective dose (20mg/kg) (P<0.05) and the effective dose (80 mg/kg) (P<0.001) of melatonin. Luzindole (2.5mg/kg), but not prazosin (0.5mg/kg), decreased the anticonvulsant effect of agmatine (20mg/kg) (P<0.05). Luzindole (2.5mg/kg), but not prazosin (0.5mg/kg), also decreased the seizure threshold when agmatine (5mg/kg) was administered before melatonin (20mg/kg); the decrease was significant compared with that of the group that received only agmatine and melatonin (P<0.001). In conclusion, melatonin and agmatine exhibit an additive effect in decreasing pentylenetetrazole-induced seizure threshold in mice, probably through ML(1/2) receptors.

Clinical uses of melatonin in pediatrics

This study analyzes the results of clinical trials of treatments with melatonin conducted in children, mostly focused on sleep disorders of different origin. Melatonin is beneficial not only in the treatment of dyssomnias, especially delayed sleep phase syndrome, but also on sleep disorders present in children with attention-deficit hyperactivity, autism spectrum disorders, and, in general, in all sleep disturbances associated with mental, neurologic, or other medical disorders. Sedative properties of melatonin have been used in diagnostic situations requiring sedation or as a premedicant in children undergoing anesthetic procedures. Epilepsy and febrile seizures are also susceptible to treatment with melatonin, alone or associated with conventional antiepileptic drugs. Melatonin has been also used to prevent the progression in some cases of adolescent idiopathic scoliosis. In newborns, and particularly those delivered preterm, melatonin has been used to reduce oxidative stress associated with sepsis, asphyxia, respiratory distress, or surgical stress. Finally, the administration of melatonin, melatonin analogues, or melatonin precursors to the infants through the breast-feeding, or by milk formula adapted for day and night, improves their nocturnal sleep. Side effects of melatonin treatments in children have not been reported. Although the above-described results are promising, specific studies to resolve the problem of dosage, formulations, and length of treatment are necessary.

Sleep and epilepsy in children and adolescents

Epilepsy and sleep disorders are considered by many to be common bedfellows. Several sleep phenomena may occur during nighttime taking a wide variety of forms and which can mimic seizures. Although most seizure sub-types have the potential to occur during sleep or wakefulness, sleep has a well-documented and strong association with specific epilepsy syndromes. Seizures in sleep also tend to occur during lighter stages of non-REM (NREM) sleep. The neurophysiologic process involved in the deepening of NREM sleep may also facilitate both seizures and IEDs. Epilepsy per se and/or seizures themselves promote sleep disruption and significantly affect the quality, quantity, and architecture of sleep. There are many causes of sleep disruption in patients with epilepsy, including inadequate sleep hygiene, coexisting sleep disorders, and circadian rhythm disturbances. Seizures themselves can disrupt sleep, even when they occur during wakefulness. Anti-epileptic drugs (AEDs) can also alter sleep in positive and negative ways, and these effects are independent of anticonvulsant actions. The end result of sleep disruption is excessive daytime sleepiness, worsening seizures, and poor quality of life. Screening for sleep disorders in the epilepsy population and appropriate intervention strategies will lead to overall improved quality of life and seizure control.

Neurotoxins: free radical mechanisms and melatonin protection

Toxins that pass through the blood-brain barrier put neurons and glia in peril. The damage inflicted is usually a consequence of the ability of these toxic agents to induce free radical generation within cells but especially at the level of the mitochondria. The elevated production of oxygen and nitrogen-based radicals and related non-radical products leads to the oxidation of essential macromolecules including lipids, proteins and DNA. The resultant damage is referred to as oxidative and nitrosative stress and, when the molecular destruction is sufficiently severe, it causes apoptosis or necrosis of neurons and glia. Loss of brain cells compromises the functions of the central nervous system expressed as motor, sensory and cognitive deficits and psychological alterations. In this survey we summarize the publications related to the following neurotoxins and the protective actions of melatonin: aminolevulinic acid, cyanide, domoic acid, kainic acid, metals, methamphetamine, polychlorinated biphenyls, rotenone, toluene and 6-hydroxydopamine. Given the potent direct free radical scavenging activities of melatonin and its metabolites, their ability to indirectly stimulate antioxidative enzymes and their efficacy in reducing electron leakage from mitochondria, it would be expected that these molecules would protect the brain from oxidative and nitrosative molecular mutilation. The studies summarized in this review indicate that this is indeed the case, an action that is obviously assisted by the fact that melatonin readily crosses the blood brain barrier.

A review of the effects of vitamins and other dietary supplements on seizure activity

The role of pharmacological and surgical management of epilepsy continues to expand, but these treatments are often associated with significant side effects and morbidity. As a result, many patients with epilepsy and their physicians alike have gained interest in the role of vitamins and other dietary supplements for seizure management. In this review, we examine the potential anticonvulsant and proconvulsant effects of commonly used dietary supplements, as well as their potential effects on cognition or behavior. Our review was conducted through a literature search focusing on clinical trials involving patients with epilepsy and their seizure response to dietary supplementation. We summarize findings from previous clinical studies and comment on practical considerations regarding dietary supplementation for patients with epilepsy.

Neuroprotection by radical avoidance: search for suitable agents

Neurodegeneration is frequently associated with damage by free radicals. However, increases in reactive oxygen and nitrogen species, which may ultimately lead to neuronal cell death, do not necessarily reflect its primary cause, but can be a consequence of otherwise induced cellular dysfunction. Detrimental processes which promote free radical formation are initiated, e.g., by disturbances in calcium homeostasis, mitochondrial malfunction, and an age-related decline in the circadian oscillator system. Free radicals generated at high rates under pathophysiological conditions are insufficiently detoxified by scavengers. Interventions at the primary causes of dysfunction, which avoid secondary rises in radical formation, may be more efficient. The aim of such approaches should be to prevent calcium overload, to reduce mitochondrial electron dissipation, to support electron transport capacity, and to avoid circadian perturbations. L-theanine and several amphiphilic nitrones are capable of counteracting excitotoxicity and/or mitochondrial radical formation. Resveratrol seems to promote mitochondrial biogenesis. Mitochondrial effects of leptin include attenuation of electron leakage. Melatonin combines all the requirements mentioned, additionally regulates anti- and pro-oxidant enzymes and is, with few exceptions, very well tolerated. In this review, the perspectives, problems and limits of drugs are compared which may be suitable for reducing the formation of free radicals.

Melatonin prevents damage elicited by the organophosphorous pesticide diazinon on the mouse testis

Organophosphates like O,O-diethyl O-2-isopropyl-6-methyl pyrimidinyl-4-g-1-phosphorothioate (diazinon) are pesticides used worldwide, which can affect both animals and man even after a single exposure. Whereas their toxicity is due to acetylcholinesterase inhibition, their secondary toxic effects have been related to free oxygen radicals. This study evaluates the effects of a single dose of diazinon and melatonin-a powerful antioxidant-on plasmatic acetylcholinesterase activity and testis histopathology in adult mice 1 and 32 days post-treatment. Diazinon diminished the plasma acetylcholinesterase activity on day 1 post-treatment, although testosterone levels remained unaffected. Morphometrical analysis showed a decrease in seminiferous epithelium height (days 1 and 32), whereas an increase in testicular superoxide dismutase (SOD) activity was detected (day 32). Melatonin pretreatment prevented every alteration induced by diazinon, except the diminution of acetylcholinesterase plasmatic activity. Testicular damage might be due to elevated concentrations of free oxygen radicals released upon diazinon exposure, inducing alterations in the DNA and promoting local apoptosis; however, antioxidant pretreatment with melatonin prevents or diminishes this damage.

Physical exercise program reverts the effects of pinealectomy on the amygdala kindling development

Several studies have demonstrated the anticonvulsant effect of melatonin. In view of the positive effects of physical exercise in epilepsy, this study analyzed the influence of physical exercise program on the amygdala kindling development in pinealectomized rats. Animals were divided into six groups: pinealectomized rats (PX), sham rats (SHAM), control rats (CTL), pinealectomized rats submitted to an aerobic exercise program (PX ATL), sham rats submitted to an aerobic exercise program (SHAM ATL) and control rats submitted to an aerobic exercise program (CTL ATL). The stimulus parameters consisted of 60 Hz frequency, diphasic square pulses of 1 ms duration applied for 2 s. The mean number of stimulations and the after-discharge (AD) duration for each stage of kindling were similar among CTL and SHAM animals. PX animals showed particular characteristics during kindling development. They did not present stage 1 and spent a shorter time in stage 2 in relation to the CTL and SHAM animals. Consequently, the AD duration and number of stimulations required to reach stage 5 was lower for the PX group when compared to the CTL and SHAM groups. Concerning the exercising groups, CTL ATL and SHAM ATL animals spent a higher time in stage 1 compared to CTL and SHAM groups. Thus, CTL ATL animals also presented a higher number of stimulations in stage 5 compared to CTL animals. The stage 1 not observed in PX animals was present in PX ATL. Consequently, the number of stimulations required to reach stage 5 was statistically higher for the PX ATL group in relation to the PX group. Our results demonstrate that the acceleration in the kindling development of pinealectomized animals can be reverted by physical exercise.

Melatonin enhances the anticonvulsant and proconvulsant effects of morphine in mice: Role for nitric oxide signaling pathway

Melatonin has different interactions with opioids including enhancing their analgesic effect and reversal of opioid tolerance and dependence. Opioids are known to exert dose-dependent anti- and proconvulsant effects in different experimental seizure paradigms. This study investigated the effect of melatonin on biphasic modulation of seizure susceptibility by morphine, in mouse model of pentylenetetrazole (PTZ)-induced clonic seizures. We further investigated the involvement of the nitric oxidergic pathway in this interaction, using a nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl-ester (L-NAME). Melatonin exerted anticonvulsant effect with doses as high as 40-80 mg/kg, but with a dose far bellow that amount (10 mg/kg), it potentiated both the anticonvulsant and proconvulsant effects of morphine on the PTZ-induced clonic seizures. Possible pharmacokinetic interaction of melatonin and morphine cannot be ruled out in the enhancement of two opposing effects of morphine on seizure threshold. L-NAME (1 mg/kg) reversed the anticonvulsant property of the combination of melatonin (10 mg/kg) plus morphine (0.5 mg/kg). Moreover, L-NAME (5 mg/kg) blocked the enhancing effect of melatonin (10 mg/kg) on proconvulsant activity of morphine (60 mg/kg). Our results indicate that co-administration of melatonin enhances both anti- and proconvulsant effects of morphine via a mechanism that may involve the nitric oxidergic pathway.

Complementary medicines in psychiatry: review of effectiveness and safety

BACKGROUND

The use of complementary medicines in those with mental health problems is well documented. However, their effectiveness is often not established and they may be less harmless than commonly assumed.

AIMS

To review the complementary medicines routinely encountered in psychiatric practice, their effectiveness, potential adverse effects and interactions.

METHOD

Electronic and manual literature search on the effectiveness and safety of psychotropic complementary medicines.

RESULTS

Potentially useful substances include ginkgo and hydergine as cognitive enhancers, passion flower and valerian as sedatives, St John's wort and s-adenosylmethionine as antidepressants, and selenium and folate to complement antidepressants. The evidence is less conclusive for the use of omega-3 fatty acids as augmentation treatment in schizophrenia, melatonin for tardive dyskinesia and 18-methoxycoronaridine, an ibogaine derivative, for the treatment of cocaine and heroin addiction.

CONCLUSIONS

Systematic clinical trials are needed to test promising substances. Meanwhile, those wishing to take psychotropic complementary medicines require appropriate advice.