Behavioral reactivity to novelty during youth as a predictive factor of stress-induced corticosterone secretion in the elderly--a life-span study in rats.
Inter- and intra-individual differences in hypothalamo-pituitary adrenal (HPA) axis activity and behavioral reactivity to novelty between young and old rats were evidenced in this longitudinal life-span study. Higher responders to novelty (HR) had a higher corticosterone secretion which showed a quicker increase with age than did the others (LR); the differences in response to novelty observed in youth were no longer apparent in the old rats. Response to novelty in youth is a predictive factor of accelerated aging of the HPA axis. These early changes, which precede the appearance of the memory deficits, may be a causal factor. Disappearance of behavioral and endocrinological inter-individual differences at 21 months highlights the importance of not restricting aging studies to old subjects.
Laboratoire de Psychobiologie des Comportements Adaptatifs, INSERM U.259, Université de Bordeaux II, France. FDELLU@pluto.scripps.edu
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D000375:Aging / Q000502:physiology*; D000818:Animals; D001143:Arousal / Q000502:physiology*; D003345:Corticosterone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007206:Individuality; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity / Q000502:physiology; D010913:Pituitary-Adrenal System / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012931:Social Environment
D003345:Corticosterone