In green iguanas, the pineal controls the circadian rhythm of body temperature but not the rhythm of locomotor activity. As part of a program to investigate the characteristics of this multioscillator circadian system, the authors studied the circadian rhythms of the electroretinographic response (ERG) and asked whether the pineal gland is necessary for the expression of this rhythm. ERGs from ...

BACKGROUND AMP protein kinase (AMPK) plays an important role in food intake and energy metabolism, which are synchronized to the light-dark cycle. In vitro, AMPK affects the circadian rhythm by regulating at least two clock components, CKIα and CRY1, via direct phosphorylation. However, it is not known whether the catalytic activity of AMPK actually regulates circadian rhythm in vivo. METHODO...

Mammalian physiology and behavior are regulated by an internal time-keeping system, referred to as circadian rhythm. The circadian timing system has a hierarchical organization composed of the master clock in the suprachiasmatic nucleus (SCN) and local clocks in extra-SCN brain regions and peripheral organs. The circadian clock molecular mechanism involves a network of transcription-translation...

Recent studies indicate that rats can increase or decrease H-reflex amplitude in response to an operant conditioning paradigm. In addition, rats also display a circadian rhythm in H-reflex amplitude. As part of the development of H-reflex conditioning in the rat as a new model for defining the plasticity underlying a simple form of learning, this study examined the relationship in the rat betwe...

The Circadian rhythm sleep disorder of the dementia is apt to cause night wandering, delirium and even sundowning syndrome. And these behaviors put a major burden on the patients themselves and their caregivers. The ratio of complication of Circadian rhythm sleep disorder in Alzheimer's disease, the major figure of dementia, is considerably high. Circadian rhythm sleep disorder in Alzheimer's d...

The circadian rhythm of pineal melatonin is the best marker of internal time under low ambient light levels. The endogenous melatonin rhythm exhibits a close association with the endogenous circadian component of the sleep propensity rhythm. This has led to the idea that melatonin is an internal sleep "facilitator" in humans, and therefore useful in the treatment of insomnia and the readjustmen...

Chlamydomonas reinhardtii expresses a well-documented circadian rhythm of phototaxis, which peaks in the subjective daytime. We find that vegetative cells also express circadian rhythms of chemotaxis to ammonium and ammonium uptake (as gauged by uptake of [(14)C]methylammonium). The chemotaxis rhythm peaks in the subjective night. Methylammonium uptake is light dependent, and its rhythm peaks a...

OBJECTIVES To investigate at what age preterm infants develop a salivary cortisol circadian rhythm and identify whether it is dependent on gestational age and/or postnatal age. To evaluate whether salivary cortisol circadian rhythm development is related to behavioral regularity. To elucidate salivary cortisol levels in preterm infants during the first year of life. METHODS This prospective, ...