Multiphotoreceptor and multioscillator system in avian circadian organization

2001 ◽  
Vol 53 (1) ◽  
pp. 43-47 ◽  
Author(s):  
Tadashi Oishi ◽  
Mikaru Yamao ◽  
Chieko Kondo ◽  
Yuka Haida ◽  
Atsuko Masuda ◽  
...  
Keyword(s):  
Circadian Organization

scholarly journals Chronothyroidology: Chronobiological Aspects in Thyroid Function and Diseases

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 426
Author(s):  
Giuseppe Bellastella ◽  
Maria Ida Maiorino ◽  
Lorenzo Scappaticcio ◽  
Annamaria De Bellis ◽  
Silvia Mercadante ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Biological Rhythms ◽  
Cellular Level ◽  
Scientific Discipline ◽  
Biological Phenomena ◽  
Pituitary Thyroid Axis ◽  
Circadian Organization ◽  
Thyroid Axis ◽  
Central Clock ◽  
Thyroid Dysfunctions

Chronobiology is the scientific discipline which considers biological phenomena in relation to time, which assumes itself biological identity. Many physiological processes are cyclically regulated by intrinsic clocks and many pathological events show a circadian time-related occurrence. Even the pituitary–thyroid axis is under the control of a central clock, and the hormones of the pituitary–thyroid axis exhibit circadian, ultradian and circannual rhythmicity. This review, after describing briefly the essential principles of chronobiology, will be focused on the results of personal experiences and of other studies on this issue, paying particular attention to those regarding the thyroid implications, appearing in the literature as reviews, metanalyses, original and observational studies until 28 February 2021 and acquired from two databases (Scopus and PubMed). The first input to biological rhythms is given by a central clock located in the suprachiasmatic nucleus (SCN), which dictates the timing from its hypothalamic site to satellite clocks that contribute in a hierarchical way to regulate the physiological rhythmicity. Disruption of the rhythmic organization can favor the onset of important disorders, including thyroid diseases. Several studies on the interrelationship between thyroid function and circadian rhythmicity demonstrated that thyroid dysfunctions may affect negatively circadian organization, disrupting TSH rhythm. Conversely, alterations of clock machinery may cause important perturbations at the cellular level, which may favor thyroid dysfunctions and also cancer.

Circadian organization of locomotor activity in the Turkish hamster (Mesocricetus brandti)

1983 ◽  
Vol 37 (2) ◽  
pp. 362-366 ◽  
Author(s):  
H. Elliott Albers ◽  
Dennis S. Carter ◽  
Janet M. Darrow ◽  
Bruce D. Goldman
Keyword(s):  
Locomotor Activity ◽  
Circadian Organization ◽  
Turkish Hamster

Circadian organization of chitin in some insect skeletons

1965 ◽  
Vol s3-106 (76) ◽  
pp. 315-325
Author(s):  
A. C. NEVILLE
Keyword(s):  
Circadian Clock ◽  
General Feature ◽  
Periplaneta Americana ◽  
Constant Darkness ◽  
Actual Rate ◽  
Rate Of Increase ◽  
Parallel Fibres ◽  
Astronomical Clock ◽  
Circadian Organization ◽  
Water Bugs

A circadian clock is shown to be involved in the control of macromolecular orientation of chitin by cells secreting and organizing insect endocuticle. Daily organization of locust endocuticle into alternating lamellate and non-lamellate layers persists in constant temperature (36° C) and constant darkness for at least 2 weeks; the freerunning period is then about 23 h, so that after a number of days the circadian clock is 180° out of phase with the astronomical clock, with which it is normally phased. The rhythm is almost independent of temperature, with a Q10 of 1.04, as contrasted with a Q10 of 2.0 for the actual rate of increase of endocuticular thickness. Locust epidermal cells differ in response to specific imposed environmental conditions according to their location in the integument. In some cells, constant low temperature uncouples chitin lamellogenesis from the circadian clock, provided that illumination (light or dark) is constant also: the result is continuously lamellate endocuticle. In other cells constant light acts as an uncoupling factor, provided that temperature (high or low) is constant also: the result in this case is continuously non-lamellate endocuticle. The circadian rhythm of chitin lamellogenesis persists in a cave cricket (Dolichopoda linderi). A similar circadian lamellogenesis rhythm occurs in the endocuticle of nymphs and adults of the cockroach Periplaneta americana. A crossed-fibre multiple-ply endocuticle in the legs and wings of giant toe-biter water bugs (Belosto-matidae) also displays circadian organization, the chitin macromolecules in any one layer lying in parallel fibres, at an angle of approximately 6o° to those in the next layer. It is suggested that daily organization of the skeleton may be a general feature of arthropods. Examples include the phenomena of timing of chitin lamellogenesis; chitin crossed-fibrillar organization; degree of fluorescence of the rubber-like protein resilin; and mineralization of crayfish gastroliths.

Circadian Organization of the Autonomic Nervous System

2000 ◽  
pp. 117-157 ◽  
Author(s):  
Ruud M. Buijs ◽  
Michael L. H. J. Hermes ◽  
Jiapei Dai ◽  
Frank Scheer ◽  
Andries Kalsbeek
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Autonomic Nervous ◽  
Circadian Organization

Circadian Organization of the Avian Annual Cycle

1985 ◽  
pp. 303-343 ◽  
Author(s):  
Albert H. Meier ◽  
Albert C. Russo
Keyword(s):  
Annual Cycle ◽  
Circadian Organization

Loss of circadian organization of sleep and wakefulness during hibernation

2002 ◽  
Vol 282 (4) ◽  
pp. R1086-R1095 ◽  
Author(s):  
Jennie E. Larkin ◽  
Paul Franken ◽  
H. Craig Heller
Keyword(s):  
Brain Temperature ◽  
Nrem Sleep ◽  
Wave Activity ◽  
Ground Squirrels ◽  
Ultradian Rhythm ◽  
Organization Of Sleep ◽  
Sleep Homeostasis ◽  
Circadian Organization ◽  
Frequency Components ◽  
Torpor Bouts

We investigated circadian and homeostatic regulation of nonrapid eye movement (NREM) sleep in golden-mantled ground squirrels during euthermic intervals between torpor bouts. Slow-wave activity (SWA; 1–4 Hz) and sigma activity (10–15 Hz) represent the two dominant electroencephalographic (EEG) frequency components of NREM sleep. EEG sigma activity has a strong circadian component in addition to a sleep homeostatic component, whereas SWA mainly reflects sleep homeostasis [Dijk DJ and Czeisler CA. J Neurosci 15: 3526–3538, 1995; Dijk DJ, Shanahan TL, Duffy JF, Ronda JM, and Czeisler CA. J Physiol (Lond) 505: 851–858, 1997]. Animals maintained under constant conditions continued to display circadian rhythms in both sigma activity and brain temperature throughout euthermic intervals, whereas sleep and wakefulness showed no circadian organization. Instead, sleep and wakefulness were distributed according to a 6-h ultradian rhythm. SWA, NREM sleep bout length, and sigma activity responded homeostatically to the ultradian sleep-wake pattern. We suggest that the loss of sleep-wake consolidation in ground squirrels during the hibernation season may be related to the greatly decreased locomotor activity during the hibernation season and may be necessary for maintenance of multiday torpor bouts characteristic of hibernating species.

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