RATIONALE Blood pressure (BP) usually decreases during nocturnal sleep and increases during daytime activities. Whether the endogenous circadian control system contributes to this daily BP variation has not been determined under appropriately controlled conditions. OBJECTIVE To determine whether there exists an endogenous circadian rhythm of BP in humans. METHODS AND RESULTS In 28 normotens...

The rhythms of spontaneously occurring seizures (spike-wave discharges, SWD) and motor activity, as well as the relationship between SWD and sleep-wake states were investigated in the WAG/Rij rat model of absence epilepsy. In order to establish whether SWD are controlled by external (Zeitgebers) or by endogenous factors such as circadian influences or the state of vigilance, the study was perfo...

Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of hum...

1. In a group of 11 normal individuals we measured glomerular filtration rate (GFR) by inulin clearances and effective renal plasma flow (ERPF) by p-aminohippurate clearances during a period of 24 h and a regimen of bedrest, identical food intake per 3 h and normal sleep/wake and light/dark cycles. 2. All subjects had a circadian rhythm for GFR with a maximum of 122 ml/min (SD 22) in the daytim...

671 Sleep-Wake Behavior in CFS—Rahman et al about the mechanisms responsible for the experience of poor quality sleep in CFS. Human sleep is part of an oscillating sleep-wake pattern following a circadian rhythm.8 These cyclical rhythms are directed by the brain’s biological “clock” located in the suprachiasmatic nucleus and cause fluctuation of body temperature, hormone levels, and sleep over ...

The pineal hormone melatonin plays a major role in circadian sleep-wake rhythm. Patients with Chronic Kidney Disease (CKD), especially those who are on hemodialysis, frequently suffer from sleep disturbances. In this review an overview is given of the classification of stages of chronic kidney disease, followed by a presentation of the circadian rhythm disorders in renal disease involving sleep...