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 ?
In the circadian pacemaker SCN, the QPCR analysis ( n = 3 for each time point, equals to n = 12 in each group) showed an obvious effect of time on the expression profile of Clock, Bmal1, Per2 in sham group [ P < 0.
The data were aligned with the melatonin rhythm which is a hormonal marker of the human brain circadian pacemaker, i.
Circadian modulation of sleep pressure, or circadian variations in susceptibility to sleep, primarily depend on the signal from the circadian pacemaker located in the hypothalamic suprachiasmatic nuclei, which is in the close interaction with various environmental and social markers [20].
Numerous studies have provided evidence to suggest the importance of the SCN as the mammalian circadian pacemaker, but in recent years, increasing studies have demonstrated a growing role for the LHb, which is thought to contribute significantly to the production of higher brain functions and may be implicated in the pathology of neurological disease [32, 36-39].
Circadian pacemaker in the Bursatella eye: properties of the rhythm and its effect on locomotor behavior.
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.
The circadian pacemaker is located in the suprachiasmatic nucleus of the hypothalamus and drives melatonin synthesis.
In humans, the primary circadian pacemaker is the suprachiasmatic nucleus (SCN).
The SCN is the site of the master circadian pacemaker in mammals, which governs the circadian rhythm of behavioral and physiological processes.
Everyone's circadian pacemaker ticks at a different rate but, as you age, your pacemaker speeds up or slows down, thus altering how the body responds to that 24-hour 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.
2 hours, (3) although daylight and social cues serve to entrain (synchronize) the circadian pacemaker to the 24-hour day ascribed by the rotation of the Earth.

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