title: Changes with age characterize circadian rhythm in telemetered core temperature of stroke-prone rats.
abstract: In a stroke-prone (SP) strain of laboratory rats, aging is associated with quantifiable changes of the circadian rhythm in body core temperature: (1) its timing becomes less tight, as revealed by a larger standard error of the acrophase (the peak in the 24-hour cosine function best approximating all data) and (2) the acrophase in old SPs occurs earlier than in young ones--quite apart from (3) a decrease in circadian amplitude reported earlier. These results gain particularly in interest in the context of the recent finding that a large (approximately 90 degrees) acrophase-advance is associated with bilateral lesions of the suprachiasmatic nuclei in inbred (non-SP) Fischer rats. These observations may be of interest to those developing models of aging functions in disorders with blood pressure elevation.
mesh_terms: D000375:Aging; D000818:Animals; D001831:Body Temperature; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D002940:Circadian Rhythm; D005260:Female; D008297:Male; D051381:Rats