Evening administration of melatonin and bright light: Interactions on the EEG during sleep and wakefulness

Abstract

SUMMARY Both the pineal hormone melatonin and light exposure are considered to play a major role in the circadian regulation of sleep. In a placebo-controlled balanced cross-over design, we investigated the acute effects of exogenous melatonin (5 mg p.o. at 20.40 hours) with or without a 3-h bright light exposure (5000 lux from 21.00 hours-24.00 hours) on subjective sleepiness, internal sleep structure and EEG power density during sleep and wakefulness in healthy young men. The acute effects of melatonin, bright light and their interaction were measured on the first day (treatment day), possible circadian phase shifts were assessed on the post-treatment day. On the treatment day, the evening rise in subjective sleepiness was accelerated after melatonin and protracted during bright light exposure. These effects were also reflected in specific changes of EEG power density in the theta/alpha range during wakefulness. Melatonin shortened and bright light increased sleep latency. REMS latency was reduced after melatonin administration but bright light had no effect. Slow-wave sleep and slow-wave activity during the first non-rapid eye movement (NREMS) episode were suppressed after melatonin administration and rebounded in the second NREMS episode, independent of whether light was co-administered or not. Self rated sleep quality was better after melatonin administration whereas the awakening process was rated as more difficult after bright light. On the post-treatment day after evening bright light, the rise in sleepiness and the onset of sleep were delayed, independent of whether melatonin was co-administered or not. Thus, although acute bright light and melatonin administration affected subjective sleepiness, internal sleep structure and EEG power density during sleep and wakefulness in a additive manner, the phase shifting effect of a single evening bright light exposure could not be blocked by exogenous melatonin. acute and phase shifting effects, circadian rhythms, EEG spectral analysis, sleep quality, sleepiness

Reduced sleep efficiency in cervical spinal cord injury; association with abolished night time melatonin secretion

“…10 Furthermore, acute suppression of the night time melatonin surge -either by light or beta-blockers -compromises sleep quality, which can be reversed by melatonin supplementation. 5,6 However, whether the chronic absence of night time melatonin secretion leads to compromised sleep is unclear. The results of the present study suggest that the absence of night time melatonin secretion results in chronically reduced sleep quality.…”

“…This demonstrates that the neural pathway for the endogenous production of melatonin passes through the cervical spinal cord. 4 Since exogenous melatonin can shorten sleep onset, improve sleep maintenance, and increase REM sleep, [5][6][7] we hypothesized that the absence of endogenous night time melatonin in subjects with cervical SCI would lead to prolonged sleep onset latency, reduced sleep efficiency, and reduced REM sleep.…”

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

“…When used near the time of habitual sleep, melatonin has produced less consistent results. Nocturnal administration has been reported to promote sleep (23,24), to have no significant clinical benefit (25) or to even increase wake time after sleep onset (26). Such variability may be related to differences in inclusion and exclusion criteria, outcome measures, hormone dose, and routes and timing of its administration.…”

What Keeps Us Awake?—the Role of Clocks and Hourglasses, Light, and Melatonin

“…It elicits time-dependent soporific effects, which have been corroborated with electrophysiological mea sures of sleepiness such as (EEG) theta activity during wakefulness (Cajochen et al, 1997b) and with brain correlates of sleepiness in an fMRI study, which highlighted the role of melatonin in priming sleep-associated brain activation patterns in anticipation of sleep (Gorfine et al, 2006). In an experiment where we blocked the natural evening increase in heat loss, subjective sleepiness, and melatonin secretion by light exposure, we could show that melatonin replace ment (5 mg) acutely recovered the evening increase in heat loss, subjective sleepiness, and also theta activity in the waking EEG (Cajochen et al, 1998;Krä uchi et al, 1997). Nighttime melatonin administration does not affect sleep consolidation or sleep efficiency (Cajochen et al, 1997a), whereas, during day time, an improvement in sleep efficiency could be found .…”

“…However, several lines of evidence suggest that endogenous melatonin levels may still play a role in consolidated sleep and/or wakefulness. Acute suppression of the nighttime melatonin surge-either by light or beta-blockers -compromises sleep quality, which can be reversed by melatonin supplementation (Cajochen et al, 1998;Van Den Heuvel et al, 1997). In a survey of 13 adult pineal surgery patients, over half the patients (54%) reported nighttime wake periods lasting 1 h or longer, 31% reported total nighttime sleep durations of less than 6 h, and 38% complained of experiencing poor or disturbed sleep every night (Macchi et al, 2002).…”