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Query: UMLS:C0917801 (insomnia)
 10,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of exogenous, supraphysiologic doses of melatonin on the total sleep time and daytime alertness of patients with chronic insomnia was examined in a double blind, single crossover study. Melatonin (75 mg per os) or identical placebo was administered at 10 PM daily to 13 insomniac patients for 14 consecutive days. A significant increase in the subjective assessment of total sleep time and daytime alertness was demonstrated with melatonin but not with placebo. However, 7 of the 13 patients reported that the active treatment had no significant effect on subjective feelings of well-being.
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PMID:The effects of exogenous melatonin on the total sleep time and daytime alertness of chronic insomniacs: a preliminary study. 191 28

Melatonin (MLT), a pineal hormone, has some sedative and hypnotic properties. To explore this effect further 20 young, healthy volunteers exposed to artificial insomnia participated in a double-blind, placebo controlled, parallel group design study. They slept in a sleep laboratory for several consecutive nights and were polygraphically monitored and subjected to a battery of psychometric tests and standardized self-report questionnaires each morning. One night all subjects received only placebo (21:00 hours) and on a second night half of them were subjected to placebo and half to MLT. On the later night blood MLT levels were measured. Polygraphic recordings revealed that MLT at bedtime decreased the time the subjects were awake before sleep onset (P less than 0.025), sleep latency (P less than 0.05), and the number of awakenings during the total sleep period (P less than 0.025), and increased sleep efficiency (P less than 0.05). In addition, it decreased sleep stage 1 (P less than 0.05) and increased sleep stage 2 (P less than 0.025). On the morning following the treatment most objective and subjective measures for awakening quality showed a trend towards improvement after MLT. One hour after its oral administration, serum MLT rose to a high pharmacological level (25817 pg/ml; median), but individual peak serum MLT levels varied by a factor of 300.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sleep laboratory investigations on hypnotic properties of melatonin. 230 9

Melatonin, produced by the pineal gland at night, has a role in regulation of the sleep-wake cycle. Among elderly people, even those who are healthy, the frequency of sleep disorders is high and there is an association with impairment of melatonin production. We investigated the effect of a controlled-release formulation of melatonin on sleep quality in 12 elderly subjects (aged 76 [SD 8] years) who were receiving various medications for chronic illnesses and who complained of insomnia. In all 12 subjects the peak excretion of the main melatonin metabolite 6-sulphatoxymelatonin during the night was lower than normal and/or delayed in comparison with non-insomniac elderly people. In a randomised, double-blind, crossover study the subjects were treated for 3 weeks with 2 mg per night of controlled-release melatonin and for 3 weeks with placebo, with a week's washout period. Sleep quality was objectively monitored by wrist actigraphy. Sleep efficiency was significantly greater after melatonin than after placebo (83 [SE 4] vs 75 [3]%, p < 0.001) and wake time after sleep onset was significantly shorter (49 [14] vs 73 [13] min, p < 0.001). Sleep latency decreased, but not significantly (19 [5] vs 33 [7] min, p = 0.088). Total sleep time was not affected. The only adverse effects reported were two cases of pruritus, one during melatonin and one during placebo treatment; both resolved spontaneously. Melatonin deficiency may have an important role in the high frequency of insomnia among elderly people. Controlled-release melatonin replacement therapy effectively improves sleep quality in this population.
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PMID:Improvement of sleep quality in elderly people by controlled-release melatonin. 749 Oct 13

We previously observed tht low oral doses of melatonin given at noon increase blood melatonin concentrations to those normally occurring nocturnally and facilitate sleep onset, as assessed using and involuntary muscle relaxation test. In this study we examined the induction of polysomnographically recorded sleep by similar doses given later in the evening, close to the times of endogenous melatonin release and habitual sleep onset. Volunteers received the hormone (oral doses of 0.3 or 1.0 mg) or placebo at 6, 8, or 9 PM. Latencies to sleep onset, to stage 2 sleep, and to rapid eye movement (REM) sleep were measured polysomnographically. Either dose given at any of the three time points decreased sleep onset latency and latency to stage 2 sleep. Melatonin did not suppress REM sleep or delay its onset. Most volunteers could clearly distinguish between the effects of melatonin and those of placebo when the hormone was tested at 6 or 8 PM. Neither melatonin dose induced "hangover" effects, as assessed with mood and performance tests administered on the morning after treatment. These data provide new evidence that nocturnal melatonin secretion may be involved in physiologic sleep onset and that exogenous melatonin may be useful in treating insomnia.
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PMID:Sleep-inducing effects of low doses of melatonin ingested in the evening. 776 78

Following abrupt phase shifts (real or simulated time zone changes, night shift work) there is desynchronisation between the internal circadian rhythms (including melatonin) and the external environment with consequent disturbances in sleep, mood and performance. In humans the pineal hormone melatonin has phase-shifting and resynchronising properties with regard to a number of circadian rhythms. Suitably timed melatonin administration hastened adaptation to phase shift and significantly improved self-rated jet lag in large numbers of time zone travellers. Preliminary results in night shift workers showed improved daytime sleep and night-time alertness. In simulated experiments, appropriately timed melatonin improved subjective sleep, alertness and performance and facilitated the readaptation of the melatonin rhythm following a rapid 9 h advance phase shift. Melatonin has also been assessed in circadian rhythm disorders with disturbed sleep (blindness and delayed sleep phase insomnia). Compared with placebo, melatonin significantly improved sleep and synchronised the sleep wake cycle in some blind subjects. Melatonin treatment significantly advanced the sleep onset time in delayed sleep phase insomnia. Taken together these findings suggest that melatonin is of benefit in facilitating adaptation to forced phase shifts and in conditions of circadian rhythm disturbance.
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PMID:Use of melatonin in circadian rhythm disorders and following phase shifts. 878 96

The hypnotic action of melatonin 5 mg p.o. was explored in 15 subjects with psychophysiological insomnia in a double-blind controlled self-report questionnaire study. Melatonin or placebo was taken at 20.00 hours for a 1-week period in random order. Effects on sleep and wakefulness were monitored by visual analogue scale and structured interview. Bedtime, sleep onset time, estimated total sleep and wake time, as well as self-rated sleep quality, were not altered by melatonin, and estimates of next-day function did not change. The period of melatonin, treatment was retrospectively correctly identified by 8 of 15 subjects. Despite unchanged ratings of night sleep quality on the last night of each treatment, 7 of 15 subjects reported that sleep had subjectively improved to a minor extent in the week of active treatment. Side-effects attributed to melatonin included headache and an odd taste in the mouth. These data indicate that melatonin is probably of no clinical value in the management of psychophysiological insomnia.
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PMID:Melatonin and insomnia. 879 4

Melatonin is being increasingly promoted as a treatment for "jet lag" and insomnia and has been suggested to act as an antioxidant in vivo. The antioxidant and potential pro-oxidant activities of melatonin were investigated in vitro. Melatonin was able to scavenge hypochlorous acid (HOCl) at a rate sufficient to protect catalase against inactivation by this molecule. Melatonin could also prevent the oxidation of 5-thio-2-nitrobenzoic acid by HOCl. Melatonin decreased the peroxidation of ox-brain phospholipids with a calculated IC50 of (210 +/- 2.3) microM. In contrast, serotonin which also scavenged HOCl, was much more effective in decreasing phospholipid peroxidation (IC50 15 +/- 5 microM). Both compounds reacted with trichloromethylperoxyl radical (CCl3O2) with rate constants of (2.7 +/- 0.2) x 10(8) and (1.2 +/- 0.1) x 10(8)M-1 s- respectively. Melatonin did not scavenge superoxide radical and weakly protected DNA against damage by the ferric bleomycin system. By contrast serotonin was weakly pro-oxidant in the ferric-bleomycin system and strongly pro-oxidant in the Fe(3+)-EDTA/H2O-deoxyribose system. Solubility restrictions precluded examination of melatonin in this system. Our data show that melatonin exerts only limited direct antioxidant activities.
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PMID:Evaluation of the antioxidant activity of melatonin in vitro. 885 41

Melatonin (MLT) is a methoxyindole secreted principally by the pineal gland. It is synthesized at night under normal environmental conditions. The endogenous rhythm of secretion is generated by the suprachiasmatic nuclei and activated by the light/dark cycle. Light is able to both suppress or activate melatonin production on the light schedule. The nycthohemeral rhythm of this hormone can be determined by repeated measurements of plasma or saliva MLT or urine sulfatoxy-MLT, the main hepatic metabolite. Melatonin can be considered as the output (the hand) of the endogenous clock. Since the regulating system follows a central and sympathetic nervous pathway, an abnormality at any level could unspecifically modify the MLT secretion, especially in patients with sympathalgia or dysautonomia. Melatonin plays the role of an endogenous zeitgeber on core temperature or sleep-wake cycle. Exogenous MLT is able to influence the endogenous secretion of the hormone according to a phase response curve. There are practical implications for this property in situations when biological rhythms are disturbed (jet-lag syndrome, delayed sleep phase syndrome, insomnia in blind people, shift-work, insomnia in elderly people). Improvement of pharmaceutical forms (controlled release preparations) or development of MLT analogs could lead to decisive progress.
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PMID:[Melatonin in humans: a biochemical marker of the circadian clock and an endogenous synchronizer]. 890 97

Melatonin is an indole hormone that is produced by the pineal gland, mainly at night, with a peak around 3.00 a.m. under normal environmental conditions. This endogenic secretion cycle is generated by the suprachiasmatic nuclei in response to the day/night alternation. Light either suppresses or entrains melatonin production according to the time of light exposure. Melatonin can be viewed as the "hand" of the internal clock and is regulated via the central nervous and sympathetic systems. Melatonin synchronizes biological cycles, particularly the temperature and sleep/wake cycles. Exogenous melatonin can influence the endogenous secretion of melatonin according to a phase response curve, an effect that provides a rationale for the use of melatonin to treat disorders of biological rhythms (rapid time-zone change syndrome, delayed sleep phase syndrome, desynchronization in blind subjects or shift workers, insomnia in the elderly). Other therapeutic indications are being considered (immune function disorders). Improvements in galenic forms (sustained-release presentations) or the development of analogs would be significant advances.
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PMID:[Melatonin: from hormone to drug?]. 897 21

Currently available as a dietary supplement, the pineal hormone melatonin is portrayed by the media as a formidable weapon against disease and aging. Accordingly, primary health care providers should be cognizant of which of its proposed uses are supported by biomedical research and which are, as yet, unproven. Melatonin entrains circadian rhythms and, thus, can treat jet lag, delayed sleep phase syndrome, and sleep disorders in the blind and in some neurologically impaired children. By virtue of its hypnotic effect, melatonin can mitigate insomnia in the elderly. Reductions in melatonin secretion have been associated with many disorders, including cardiovascular disease, Alzheimer's, diabetes, SIDS, and aging; however, melatonin's role in their etiology and/or pathophysiology is unproven. Preliminary studies suggest a possible adjuvant therapeutic role for melatonin in cancer therapy. Melatonin secretion is reduced by alcohol, caffeine, and some commonly prescribed drugs. Since tolerance, fatigue, and other side effects have been reported, melatonin use on consecutive nights should be avoided and only the lowest effective hypnotic dose should be taken.
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PMID:Melatonin: media hype or therapeutic breakthrough? 905 17


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