Vitamin B12 (VB12) has been reported to normalize the entrainment of circadian rhythms in the non-24-h sleep wake cycle and delayed sleep phase insomnia in humans. The purpose of this work was to clarify whether the peripheral administration of VB12 has any sleep-promoting effect on the sleep-wake rhythm in freely moving rats. After a baseline day of saline infusion. VB12 (500 micrograms/kg/day...

The human circadian system is normally synchronised with the solar day, insuring that alertness and performance peak during daytime hours and consolidated sleep occurs during the night. In circadian rhythm sleep disorders, the pattern of sleep-wake is misaligned with the patient's circadian system or the external environment, resulting in insomnia, fatigue, and deterioration in performance. App...

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, or changes in rhythms' amplitude, being documented in patients with major depressive disorder (MDD), seasonal affective disorder or bipolar disorder. The disturbances in the amplitude and rhythm of melatonin secretio...

The pineal hormone melatonin is able to shift the timing of circadian rhythms, including the sleep-wake cycle, and to promote sleep. Melatonin agonists with similar properties have therapeutic potential for the treatment of circadian rhythm sleep disorders. Depression is specifically targeted by agomelatine, which is also a serotonin-2C (5-HT(2C)) antagonist.

The purpose of this study was to evaluate homeostatic and circadian sleep process in 'larks' and 'owls' under daily life conditions. Core body temperature, subjective sleepiness and waking electroencephalogram (EEG) theta-alpha activity (6.25-9 Hz) were assessed in 18 healthy men (nine morning and nine evening chronotypes, 21.4 +/- 1.9 years) during a 36-h constant routine that followed a week ...

(Section numbers run consecutively through Parts I and II) 9.0 Introduction 10.0 CRSDs and Molecular Genetics 11.0 Advanced Sleep Phase Disorder (ASPD) 11.1 Diagnostic Issues 11.2 Risk Factors 11.2.1 Age 11.2.2 Gender 11.2.3 Light Exposure 11.3 Assessment Tools 11.3.1 Sleep Logs and Actigraphy 11.3.2 Morningness-Eveningness Questionnaire (MEQ) 11.3.3 Polysomnography (PSG) 11.3.4 Phase Markers 1...

Effects of forced sleep-wake schedules with and without physical exercise were examined on the human circadian pacemaker under dim light conditions. Subjects spent 15 days in an isolation facility separately without knowing the time of day and followed a forced sleep-wake schedule of a 23 h 40-min period for 12 cycles, and physical exercise was imposed twice per waking period for 2 h each with ...