circadian pacemaker

circadian pacemaker

A cluster of hypothalamic neurons, the activity of which fluctuates in ± 24-hour cycles, resides in the pineal gland—an aggregate of parenchymal cells surrounded by a neuroglial network with direct retinal innervation (retinohypothalamic tract), which is thought to act by secreting melatonin at night—weighs 100–180 mg, and derives embryologically from the ependyma at the roof of the third ventricle. In rats, the biogenic oscillator/internal clock resides in the ventral hypothalamus; in hamsters, in the suprachiasmatic nucleus. The circadian pacemaker influences the pineal gland.

circadian pacemaker

A cluster of neurons, the activity of which fluctuates in ± 24 hr cycles; the CP resides in the pineal gland, weighs 100-180 mg, and derives embryologically from the ependyma at the roof of the 3rd ventricle; the CP influences the pineal gland, which produces melatonin at night. See Bright light therapy, Chronotherapy, Circadian rhythm, Melatonin, Seasonal affective disorder, Zeitgeber.
References in periodicals archive ?
As is the case in a mutation of the twenty-four gene, when the Ataxin-2 gene is not present, very little PER protein is found in the circadian pacemaker neurons of the brain, and the fly's sleep-wake rhythm is disturbed.
Mop3 is an essential component of the master circadian pacemaker in mammals.
In humans, the primary circadian pacemaker is the suprachiasmatic nucleus (SCN).
N24HSWD occurs when individuals, primarily blind with no light perception, are unable to synchronize their endogenous circadian pacemaker to the 24-hour light/dark cycle.
For instance, exposure to a few hours of ordinary room light of about 100 lux brightness (which most people get every night before they go to bed) can significantly reset the human circadian pacemaker, Jamie Zeitzer and colleagues reported in the September 2005 American Journal of Physiology--Regulatory, Integrative and Comparative Physiology.
It promotes wakefulness as input from the retina goes to the suprachiasmatic nucleus (SCN) of the hypothalamus, which contains a circadian pacemaker.
After that time, the influence of the clock - known as the endogenous circadian pacemaker (ECP) - diminishes significantly and the quantity and quality of sleep drops.
However, because destroying the SCN does not affect the body clock that paces feeding behavior, the circadian pacemaker for feeding must be somewhere else, Dr.
Free-running circadian period is also a sensitive meter of the intensity of ambient light transduced to the circadian pacemaker.
This meant that their circadian pacemaker still responded to light although consciously they could perceive no light.
notatum and other eukaryotic organisms must have an input which could be the light signal, a master clock or a central circadian pacemaker that directs and integrates the light signal and dictates the day-night cycle of activities, and the output which is the circadian gene expression (Wolf et al, 2001).
The circadian control of the body rests with the SCN, which is considered the circadian pacemaker, or clock, of the body.

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