Abstract
We assessed whether alterations in endogenous circadian rhythm of core temperature (CRT) in aging rats are associated with chronological time or with a biological marker of senescence, i.e., spontaneous rapid body weight loss. CRT was measured in male Fischer 344 (F344) rats beginning at age 689 days and then continuously until death. Young rats were also monitored. The rats were housed under constant dim red light at 24-26°C, and core temperature was recorded every 10 min via biotelemetry. The CRT amplitude of the body weight-stable (presenescent) old rats was significantly less than that of young rats at all analysis periods. At the onset of spontaneous rapid weight loss (senescence), all measures of endogenous CRT differed significantly from those in the presenescent period. The suprachiasmatic nucleus (a circadian pacemaker) of the senescent rats maintained its light responsiveness as determined by an increase in c-fos expression after a brief light exposure. These data demonstrate that some characteristics of the CRT are altered slowly with chronological aging, whereas others occur rapidly with the onset of senescence.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 276 |
| Issue number | 3 45-3 |
| State | Published - Mar 1999 |
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Keywords
- Age-related anorexia
- Aging
- Biological age
- Hypothalamus
- Suprachiasmatic nucleus
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
Alterations in endogenous circadian rhythm of core temperature in senescent Fischer 344 rats. / Mcdonald, Roger B.; Hoban-Higgins, Tana M.; Ruhe, Rodney C.; Fuller, Charles A.; Horwitz, Barbara A.
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 276, No. 3 45-3, 03.1999.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Alterations in endogenous circadian rhythm of core temperature in senescent Fischer 344 rats
AU - Mcdonald, Roger B.
AU - Hoban-Higgins, Tana M.
AU - Ruhe, Rodney C.
AU - Fuller, Charles A.
AU - Horwitz, Barbara A
PY - 1999/3
Y1 - 1999/3
N2 - We assessed whether alterations in endogenous circadian rhythm of core temperature (CRT) in aging rats are associated with chronological time or with a biological marker of senescence, i.e., spontaneous rapid body weight loss. CRT was measured in male Fischer 344 (F344) rats beginning at age 689 days and then continuously until death. Young rats were also monitored. The rats were housed under constant dim red light at 24-26°C, and core temperature was recorded every 10 min via biotelemetry. The CRT amplitude of the body weight-stable (presenescent) old rats was significantly less than that of young rats at all analysis periods. At the onset of spontaneous rapid weight loss (senescence), all measures of endogenous CRT differed significantly from those in the presenescent period. The suprachiasmatic nucleus (a circadian pacemaker) of the senescent rats maintained its light responsiveness as determined by an increase in c-fos expression after a brief light exposure. These data demonstrate that some characteristics of the CRT are altered slowly with chronological aging, whereas others occur rapidly with the onset of senescence.
AB - We assessed whether alterations in endogenous circadian rhythm of core temperature (CRT) in aging rats are associated with chronological time or with a biological marker of senescence, i.e., spontaneous rapid body weight loss. CRT was measured in male Fischer 344 (F344) rats beginning at age 689 days and then continuously until death. Young rats were also monitored. The rats were housed under constant dim red light at 24-26°C, and core temperature was recorded every 10 min via biotelemetry. The CRT amplitude of the body weight-stable (presenescent) old rats was significantly less than that of young rats at all analysis periods. At the onset of spontaneous rapid weight loss (senescence), all measures of endogenous CRT differed significantly from those in the presenescent period. The suprachiasmatic nucleus (a circadian pacemaker) of the senescent rats maintained its light responsiveness as determined by an increase in c-fos expression after a brief light exposure. These data demonstrate that some characteristics of the CRT are altered slowly with chronological aging, whereas others occur rapidly with the onset of senescence.
KW - Age-related anorexia
KW - Aging
KW - Biological age
KW - Hypothalamus
KW - Suprachiasmatic nucleus
UR - http://www.scopus.com/inward/record.url?scp=0032920073&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032920073&partnerID=8YFLogxK
M3 - Article
C2 - 10070144
AN - SCOPUS:0032920073
VL - 276
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 3 45-3
ER -