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 normotensi...

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 normotensi...

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...

PURPOSE The authors addressed three questions concerning the circadian rhythm of aqueous humor protein concentration in rabbits. First, is there an endogenous oscillator for this circadian rhythm? Second, does a circadian rhythm occur for individual aqueous humor protein components? Third, what is the role of ocular sympathetic nerves, which are more active in the dark phase, in this circadian ...

BACKGROUND Genes underlying circadian rhythm generation are expressed in many tissues. We explore a role for circadian rhythms in the timing and efficacy of mouse reproduction and development using a genetic approach. METHODS We compare fecundity in Clock(Delta19) mutant mice (a dominant-negative protein essential for circadian rhythm activity) and in Vipr2-/- null mutant mice (affecting the ...

Space travelers are reported to experience circadian rhythm disruption during spaceflight. However, how the space environment affects circadian rhythm is yet to be determined. The major focus of this study was to investigate the effect of spaceflight on the Drosophila circadian clock at both the behavioral and molecular level. We used China's Shenzhou-9 spaceship to carry Drosophila. After 13 d...

Fibromyalgia syndrome (FMS) is a complex chronic condition causing widespread pain and variety of other symptoms. It produces pain in the soft tissues located around joints throughout the body. FMS has unknown etiology and its pathophysiology is not fully understood. However, abnormality in circadian rhythm of hormonal profiles and cytokines has been observed in this disorder. Moreover, there a...

few researches have been performed on the circadian rhythm of oxidants and anti-oxidants and these studies have demonstrated different results. the aim of this study was to investigate the circadian variation of mda, pc and sod in non-athlete young men. the research method of this study was semi-experimental. for this purpose, 10 non-athlete active students (mean age: 23.2±2.57 years old, heigh...

The suprachiasmatic nucleus (SCN) is the site of the master circadian clock in mammals. The SCN neural network plays a critical role in expressing the tissue-level circadian rhythm. Previously, we demonstrated postnatal changes in the SCN network in mice, in which the clock gene products CRYPTOCHROMES (CRYs) are involved. Here, we show that vasoactive intestinal polypeptide (VIP) signaling is e...

When administered to humans the pineal honnone me\atonin can phase shift a number of circadian rhythms. This property has prompted the investigation of exogenous melatonin in sleep disorders known to have an underlying chronophysiological basis (i.e. circadian rhythm sleep disorders). Both in field and simulated studies of jet lag and shift work suitably timed melatonin improved sleep and, in s...