Effect of a short photoperiod on circadian rhythms of body temperature and motor activity in old rats

2002 ◽  
Vol 444 (1-2) ◽  
pp. 73-79 ◽  
Author(s):  
C. Benstaali ◽  
A. Bogdan ◽  
Y. Touitou
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Motor Activity ◽  
Short Photoperiod ◽  
Old Rats

Circadian rhythms of body temperature and motor activity in rodents

Life Sciences ◽  
2001 ◽  
Vol 68 (24) ◽  
pp. 2645-2656 ◽  
Author(s):  
C. Benstaali ◽  
A. Mailloux ◽  
A. Bogdan ◽  
A. Auzéby ◽  
Y. Touitou
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Motor Activity

Changes in circadian rhythms of body temperature and sleep in old rats

1995 ◽  
Vol 269 (1) ◽  
pp. R208-R214 ◽  
Author(s):  
H. Li ◽  
E. Satinoff
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Eye Movement ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Female Rats ◽  
Rapid Eye Movement ◽  
Adult Rats ◽  
Old Rats ◽  
The Stability

We examined the relationship between circadian rhythms of body temperature (CTR) and sleep in adult and old female rats. Body temperature was recorded telemetrically for months and sleep for 24 h in a 12:12-h light-dark cycle at 23 degrees C. Some old rats had robust CTRs (old good), and some had unstable or absent CTRs (old unstable). Old unstable rats had lower daily mean body temperatures, smaller daily amplitudes, and a more advanced CTR phase than adult rats and old good rats. Old good rats matched adult rats in all measures. In old good rats, circadian parameters of sleep were normal, whereas in old unstable rats the amplitudes of slow-wave and rapid eye movement sleep were decreased, although the amounts were equivalent. Rhythmic parameters of sleep correlate well with the stability or instability of the CTR, whereas homeostatic regulation of rapid eye movement and slow-wave sleep do not seem to be impaired during aging and are independent of the stability of the CTR.

Effects of a novel melatonin analog on circadian rhythms of body temperature and activity in young, middle-aged, and old rats

1993 ◽  
Vol 14 (6) ◽  
pp. 565-569 ◽  
Author(s):  
G.C. Koster-Van Hoffen ◽  
M. Mirmiran ◽  
N.P.A. Bos ◽  
W. Witting ◽  
P. Delagrange ◽  
...  
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Middle Aged ◽  
Old Rats

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.

Ambulatory Estimation of Circadian Rhythms Shows Core Body Temperature Phase Precedes Slow Wave Sleep Phase in the Normal Elderly

2020 ◽  
Vol 87 (9) ◽  
pp. S251
Author(s):  
Esther Blessing ◽  
Ankit Paresh ◽  
Arleener Turner ◽  
Andrew Varga ◽  
David Rapoport ◽  
...  
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Core Body Temperature ◽  
Temperature Phase ◽  
Sleep Phase ◽  
Core Body

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.

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