Effects of aging on entrainment and rate of resynchronization of circadian locomotor activity

P. C. Zee*, R. S. Rosenberg, F. W. Turek

*Corresponding author for this work

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

The phase angle of entrainment of the circadian rhythm of the locomotor activity rhythm to a light-dark (LD) cycle was examined in young (2-5 mo old) and middle-aged (13-16 mo old) hamsters. An age-related phase advance in the onset of locomotor activity relative to lights off was seen during stable entrainment to a 14:10-h LD cycle. In addition, the effects of age on the rate of reentrainment of the circadian rhythm of locomotor activity were examined by subjecting young and middle-aged hamsters to either an 8-h advance or delay shift of the LD cycle. Middle-aged hamsters resynchronized more rapidly after a phase advance of the LD cycle than did young hamsters, whereas young hamsters were able to phase delay more rapidly than middle-aged hamsters. The age-related phase advance of activity onset under entrained conditions, and the alteration of responses in middle-aged hamsters reentraining to a phase-shifted LD cycle, may be due to the shortening of the free-running period of the circadian rhythm of locomotor activity with advancing age that has previously been observed in this species.

Original languageEnglish (US)
Pages (from-to)R1099-R1103
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume263
Issue number5 32-5
DOIs
StatePublished - 1992

Keywords

  • phase angle
  • reentrainment

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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