No abstract available.
Melatonin*

Circadian rhythm is an essential biological process that regulates the sleep-wake cycle，hormone secretion，and metabolism，and the stability of circadian rhythm is crucial for maintaining normal cognitive function. Melatonin （MT），a key hormone secreted by the pineal gland，is involved in the regulation of circadian rhythm and thus has a significant impact on cognitive function. This article systematically reviews the multiple mechanisms by which MT regulates cognitive function through circadian rhythm，including improving sleep quality，promoting the clearance of metabolic waste by the glymphatic system，exerting antioxidant and anti-inflammatory effects，and regulating neuronal activity and the improvement of synaptic plasticity. In addition，this article also discusses the association between circadian rhythm disorders and neurodegenerative diseases. Future studies are needed in the future to further clarify the neuroprotective mechanisms of MT，in order to provide new insights for the prevention and treatment of cognitive impairment.
Melatonin

No Abstract Available.
Melatonin* ; Pineal Gland*

Animals ; Humans ; Melatonin ; physiology ; Receptors, Melatonin ; physiology ; Signal Transduction ; physiology

PURPOSE: To investigate the effect of intravitreal melatonin on retina in rabbit. METHODS: In four pigmented rabbit, melatonin was intravitreally injected 100 mu g/0.1 ml, 300 mu g/0.1 ml concentration in left eye, DMSO was injected in right eye as control. we examined gross fundus finding and electroretinogram and then light and electronic microscopic findings at 24 hours and 1 week with both eye. RESULTS: intravitreally melatonin injected eye at 100 mu g/0.1 ml, 300 mu g/0.1 ml concentration and control eye at 1 day and 1 week, significant difference was not shown in gross fundus finding, electroretinogram, light and electronic microscopic finding. Additionally edema, toxic effect change was not found in retina. CONCLUSIONS: Intravitreally injected melatonin has not influenced on retina grossly, histologically, physiologically at 100 mu g/0.1 ml and 300 mu g/0.1 ml concentration. Further study is required about toxic effect of melatonin over 300 mu g/0.1 ml concentration and clinical usefulness of melatonin in retina.
Dimethyl Sulfoxide ; Edema ; Intravitreal Injections ; Melatonin* ; Retina*

OBJECTIVE: Light pollution has become a social and health issue. We performed an experimental study to investigate impact of dim light at night (dLAN) on sleep in female subjects, with measurement of salivary melatonin. METHODS: The 25 female subjects (Group A: 12; Group B: 13 subjects) underwent a nocturnal polysomnography (NPSG) session with no light (Night 1) followed by an NPSG session randomly assigned to two conditions (Group A: 5; Group B: 10 lux) during a whole night of sleep (Night 2). Salivary melatonin was measured before and after sleep on each night. For further investigation, the female and male subjects of our previous study were collected (48 subjects), and differences according to gender were compared. RESULTS: dLAN during sleep was significantly associated with decreased total sleep time (TST; F=4.818, p=0.039), sleep efficiency (SE; F=5.072, p=0.034), and Stage R latency (F=4.664, p=0.041) for female subjects, and decreased TST (F=14.971, p<0.001) and SE (F=7.687, p=0.008), and increased wake time after sleep onset (F=6.322, p=0.015) and Stage R (F=5.031, p=0.03), with a night-group interaction (F=4.579, p=0.038) for total sample. However, no significant melatonin changes. There was no significant gender difference of the impact of dLAN on sleep, showing the negative changes in the amount and quality of sleep and the increase in rapid eye movement (REM) sleep in the both gender group under 10 lux condition. CONCLUSION: We found a negative impact of exposure to dLAN on sleep in female as well as in merged subjects. REM sleep showed a pronounced increase under 10 lux than under 5 lux in merged subjects, suggesting the possibility of subtle influences of dLAN on REM sleep.
Female* ; Humans ; Male* ; Melatonin ; Polysomnography ; Sleep, REM

Circadian clock is an internal mechanism evolved to adapt to cyclic environmental changes, especially diurnal changes. Keeping the internal clock in synchronization with the external clock is essential for health. Mismatch of the clocks due to phase shift or disruption of molecular clocks may lead to circadian disorders, including abnormal sleep-wake cycles, as well as disrupted rhythms in hormone secretion, blood pressure, heart rate, body temperature, etc. Long-term circadian disorders are risk factors for various common critical diseases such as metabolic diseases, cardiovascular diseases, and tumor. To prevent or treat the circadian disorders, scientists have conducted extensive research on the function of circadian clocks and their roles in the development of diseases, and screened hundreds of thousands of compounds to find candidates to regulate circadian rhythms. In addition, melatonin, light therapy, exercise therapy, timing and composition of food also play a certain role in relieving associated symptoms. Here, we summarized the progress of both drug- and non-drug-based approaches to prevent and treat circadian clock disorders.
Circadian Rhythm ; Circadian Clocks ; Melatonin/physiology*

The selective melatonin receptor agonism effect of ramelteon is useful for insomnia. Here we wanted to present a refractory chronic migraine case, who had significant improvements in migraine after using ramelteon. The possible mechanism for the ramelteon in the migraine relief might be related to melatonin effects.
Felodipine ; Melatonin ; Migraine Disorders* ; Receptors, Melatonin ; Sleep Initiation and Maintenance Disorders ; Sleep Wake Disorders

Recently, melatonergic agents have been gaining much interest in the treatment of mood disorders. The elucidation of the underlying biological mechanisms related to the melatonergic system in mood disorders is warranted to ensure the proper use of melatonergic agents. Changes of the melatonergic system have been investigated in several studies of patients with bipolar disorder (BP) and depression. Accumulating evidence has indicated that patients with BP might exhibit abnormal melatonin secretion patterns, increased light-induced melatonin suppression, altered pineal gland volume, genetically abnormal melatonin synthesis enzyme, and modified melatonin receptors. In this review, the findings of studies performed to explore the association between the melatonergic system and BP are discussed. Moreover, the interpretations and limitations of these findings are described.
Bipolar Disorder ; Depression ; Humans ; Melatonin ; Mood Disorders ; Pineal Gland ; Receptors, Melatonin

PURPOSE: This study aims to evaluate and compare the efficacy of exogenous melatonin associated with desmopressin (dDAVP) and dietary recommendations. METHODS: A total of 189 patients were enrolled from the Service of Pediatrics, Campus Bio-Medico University Hospital of Rome, from January 2013 to June 2015. Of the 189 original patients, 153 children, aged between 5 and 14 years (mean age, 8.7 years) were included in the study. After clinical evaluation and a 3-month period of observation without treatment, children were assigned to receive treatment in one of 3 groups: group 1, dDAVP at a dose of 120 mcg a day (Minirin); group 2, dDAVP at a dose of 120 mcg and dietary recommendations; or group 3, dDAVP at a dose of 120 mcg, dietary recommendations, and melatonin at a dose of 1 mg a day (Melamil plus). Each patient was treated for 3 months. RESULTS: After the 3 months of therapy, a desiderable response was achieved in 30 of 51 patients (58.82%) treated with dDAVP, 35 of 53 patients (66.04%) treated with dDAVP and dietary recommendations, and 35 of 49 patients (71.43%) treated with dDAVP, dietary recommendations, and melatonin. CONCLUSIONS: Although not statistically significant, the results show that the association between dDAVP treatment with dietary recommendations and melatonin could be considered a safe and effective treatment of NE. Considering that the statistically insignificant results might be due to the small sample size, the study will be continued to increase the number of subjects.
Child ; Deamino Arginine Vasopressin* ; Enuresis* ; Humans ; Melatonin ; Pediatrics ; Sample Size