scholarly journals Entrainment of circadian rhythms of locomotor activity by ambient temperature cycles in the dromedary camel

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hicham Farsi ◽  
Mohamed R. Achaâban ◽  
Mohammed Piro ◽  
Béatrice Bothorel ◽  
Mohammed Ouassat ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Ambient Temperature ◽  
Cycle Phase ◽  
Dromedary Camel ◽  
Dark Cycle ◽  
Free Running ◽  
Activity Onset ◽  
Master Clock

Abstract In the dromedary camel, a well-adapted desert mammal, daily ambient temperature (Ta)-cycles have been shown to synchronize the central circadian clock. Such entrainment has been demonstrated by examining two circadian outputs, body temperature and melatonin rhythms. Locomotor activity (LA), another circadian output not yet investigated in the camel, may provide further information on such specific entrainment. To verify if daily LA is an endogenous rhythm and whether the desert Ta-cycle can entrain it, six dromedaries were first kept under total darkness and constant-Ta. Results showed that the LA rhythm free runs with a period of 24.8–24.9 h. After having verified that the light–dark cycle synchronizes LA, camels were subjected to a Ta-cycle with warmer temperatures during subjective days and cooler temperatures during subjective nights. Results showed that the free-running LA rhythm was entrained by the Ta-cycle with a period of exactly 24.0 h, while a 12 h Ta-cycle phase advance induced an inversion of the LA rhythm and advanced the acrophase by 9 h. Similarly, activity onset and offset were significantly advanced. All together, these results demonstrate that the Ta-cycle is a strong zeitgeber, able to entrain the camel LA rhythm, hence corroborating previous results concerning the Ta non-photic synchronization of the circadian master clock.

Internal synchronization among several circadian rhythms in rats under constant light

1978 ◽  
Vol 235 (5) ◽  
pp. R243-R249 ◽  
Author(s):  
K. I. Honma ◽  
T. Hiroshige
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Continuous Light ◽  
Biological Rhythms ◽  
Plasma Corticosterone ◽  
Dark Cycle ◽  
Internal Oscillator ◽  
Free Running ◽  
Phase Angles

Three biological rhythms (locomotor activity, body temperature, and plasma corticosterone) were measured simultaneously in individual rats under light-dark cycles and continuous light. Spontaneous locomotor activity was recorded on an Animex and body temperature was telemetrically monitored throughout the experiments. Blood samples were obtained serially at 2-h intervals on the experimental days. Phase angles of these rhythms were calculated by a least-squares spectrum analysis. Under light-dark cycles, the acrophases of locomotor activity, body temperature, and plasma corticosterone were found at 0029, 0106, and 1940 h, respectively. When rats were exposed to 200 lx continuous light, locomotor activity and body temperature showed free-running rhythms with a period of 25.2 h on the average. Plasma corticosterone levels determined at 12 days after exposure to continuous light exhibited a circadian rhythm with the acrophase shifted to 0720. The acrophases of locomotor activity and body temperature, determined simultaneously on the same day, were found to be located at 1303 and 1358 h, respectively. Phase-angle differences among the three rhythms on the 12th day of continuous light were essentially the same with those under the light-dark cycle. These results suggest that circadian rhythms of locomotor activity, body temperature, and plasma corticosterone are most probably coupled to a common internal oscillator in the rat.

scholarly journals Effects of Resveratrol on Daily Rhythms of Locomotor Activity and Body Temperature in Young and Aged Grey Mouse Lemurs

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Fabien Pifferi ◽  
Alexandre Dal-Pan ◽  
Solène Languille ◽  
Fabienne Aujard
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Biological Clock ◽  
The Elderly ◽  
Aged Mouse ◽  
Dark Cycle ◽  
Temperature Rhythm ◽  
Mouse Lemurs ◽  
Body Temperature Rhythm ◽  
Activity Onset

In several species, resveratrol, a polyphenolic compound, activates sirtuin proteins implicated in the regulation of energy balance and biological clock processes. To demonstrate the effect of resveratrol on clock function in an aged primate, young and aged mouse lemurs(Microcebus murinus)were studied over a 4-week dietary supplementation with resveratrol. Spontaneous locomotor activity and daily variations in body temperature were continuously recorded. Reduction in locomotor activity onset and changes in body temperature rhythm in resveratrol-supplemented aged animals suggest an improved synchronisation on the light-dark cycle. Resveratrol could be a good candidate to restore the circadian rhythms in the elderly.

Endogenous ultradian rhythms in rats exposed to prolonged continuous light

1978 ◽  
Vol 235 (5) ◽  
pp. R250-R256 ◽  
Author(s):  
K. I. Honma ◽  
T. Hiroshige
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Continuous Light ◽  
Plasma Corticosterone ◽  
Ultradian Rhythm ◽  
Ultradian Rhythms ◽  
Serial Sampling ◽  
Free Running

Circadian rhythms of locomotor activity, body temperature, and plasma corticosterone were determined simultaneously in individual rats that were exposed to 200 lx continuous light for over 3 mo. Free-running circadian rhythms of locomotor activity persisted for about 2 mo under continuous light and then the rhythms gradually decomposed. After 3 mo of exposure, circadian rhythms disappeared and activity bursts of 1- to 2-h duration manifested themselves several times during a 24-h period. Body temperature also exhibited several bursts of fluctuation and these bursts were closely correlated in their temporal sequence with those of locomotor activity. A least-squares spectrum analysis revealed that the burst had regular 4- to 6-h periods. Plasma corticosterone, determined by serial sampling at 2-h intervals from individual rats, also exhibited several secretion episodes in a day. These episodic secretions synchronized with bursts of locomotor activity. These results suggest that the ultradian component, manifested under prolonged continuous light, is a fundamental unit of the circadian rhythm and an oscillator for the ultradian rhythm is common to the three functions examined.

scholarly journals Drugs of Abuse Can Entrain Circadian Rhythms

2007 ◽  
Vol 7 ◽  
pp. 203-212 ◽  
Author(s):  
Ann E. K. Kosobud ◽  
Andrea G. Gillman ◽  
Joseph K. Leffel ◽  
Norman C. Pecoraro ◽  
G. V. Rebec ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Drug Metabolism ◽  
Suprachiasmatic Nucleus ◽  
Drugs Of Abuse ◽  
Social Cues ◽  
Dark Cycle ◽  
Drug Reward ◽  
Locomotor Stimulation ◽  
Almost All

Circadian rhythms prepare organisms for predictable events during the Earth's 24-h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

Light-induced suppression of the rat circadian system

1995 ◽  
Vol 268 (5) ◽  
pp. R1111-R1116 ◽  
Author(s):  
P. Depres-Brummer ◽  
F. Levi ◽  
G. Metzger ◽  
Y. Touitou
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Continuous Light ◽  
Circadian System ◽  
Short Exposure ◽  
Complete Suppression ◽  
Continuous Darkness

In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.

Organization of rat circadian rhythms during daily infusion of melatonin or S20098, a melatonin agonist

1999 ◽  
Vol 277 (3) ◽  
pp. R812-R828 ◽  
Author(s):  
B. Pitrosky ◽  
R. Kirsch ◽  
A. Malan ◽  
E. Mocaer ◽  
P. Pevet
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Phase Response Curve ◽  
Constant Darkness ◽  
Time Interval ◽  
General Activity ◽  
Activity Peak ◽  
Free Running ◽  
Wheel Activity ◽  
Free Running Period

Daily administration of melatonin or S20098, a melatonin agonist, is known to entrain the free-running circadian rhythms of rats. The effects of the duration of administration on entrainment were studied. The animals demonstrated free-running circadian rhythms (running-wheel activity, body temperature, general activity) in constant darkness. Daily infusions of melatonin or S20098 for 1, 8, or 16 h entrained the circadian rhythms to 24 h. Two daily infusions of 1 h (separated by 8 h) entrained the activity peak within the shorter time interval. The entraining properties of melatonin and S20098 were similar and were affected neither by pinealectomy nor by infusion of 1- or 8-h duration. However, with 16-h infusion, less than half of the animals became entrained. Once entrained, the phase angle between the onset of infusion and the rhythms (onset of activity or acrophase of body temperature) increased with the duration of infusion. Before entrainment, the free-running period increased with the duration of infusion, an effect that was not predictable from the phase response curve.

Transient circadian internal desynchronization after light-dark phase shift in monkeys

1977 ◽  
Vol 232 (1) ◽  
pp. R31-R37 ◽  
Author(s):  
M. C. Moore-Ede ◽  
D. A. Kass ◽  
J. A. Herd
Keyword(s):  
Body Temperature ◽  
Saimiri Sciureus ◽  
Cycle Phase ◽  
Dark Phase ◽  
Dark Cycle ◽  
Water Excretion ◽  
Urinary Potassium ◽  
Timing System ◽  
Internal Desynchronization ◽  
Circadian Timing System

In four conscious chair-acclimatized squirrel monkeys (Saimiri sciureus) studied with lights on (600 lx) from 0800 to 2000 h daily (LD 12:12), prominent 24-h rhythms in feeding, drinking, activity, body temperature, and urinary potassium, sodium, and water excretion were seen. When the monkeys were subjected to 36 h of darkness followed by 36 h of light each variable demonstrated a circadian rhythm which was not passively dependent on the light-dark cycle. After the 24-h light-dark cycle was abruptly phase-delayed by 8 h, all the rhythms resynchronized with the new light-dark cycle phase, demonstrating that light-dark cycles are an effective zeitgeber. However, the resynchronization of the rhythms of feeding, drinking, activity, and body temperature was 90% complete within approximately 2 days while the 90% resynchronization of the urinary rhythms took approximately 5 days. These results suggest that the circadian timing system in S. sciureus may consist of several spontaneously oscillating units which can become transiently uncoupled during pertubations of environmental time cues.

scholarly journals Photoperiodic modulation of circadian rhythms in the silk gland protein profiles of Bombyx mori and its influence on the silk productivity and quality

2010 ◽  
Vol 2 (1) ◽  
pp. 48-56 ◽  
Author(s):  
B. Sailaja ◽  
S. Sivaprasad
Keyword(s):  
Circadian Rhythms ◽  
Bombyx Mori ◽  
Continuous Light ◽  
Silk Gland ◽  
Protein Profiles ◽  
Dark Cycle ◽  
Response Curves ◽  
Silk Proteins ◽  
Free Running ◽  
Clock Shift

Circadian rhythms in the silk gland protein profiles of Bombyx mori were analyzed under 12 h light and 12 h dark cycle (LD), continuous light (LL) and continuous dark (DD) conditions. The phase response curves of protein rhythms indicate the prevalence of a series of silk cycles, each comprising three phases; transcription, translation and consolidation of silk proteins. In the 24h- protein rhythm, the silk cycle repeats every 3h, 42 m under LD, 2h, 36m under LL and 3h under DD. The light and dark conditions advanced the rhythm of each silk cycle by 48m and 24m respectively. As a result the silk gland completes 7 rounds of protein synthesis under LD, 9 rounds under LL and 8 rounds under DD during the 24h-free running time of the rhythm. The light-induced clock-shift in the protein rhythm caused significant gains in economic parameters of sericulture with positive signals for enhancing silk productivity and quality.

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