Age-related changes in circadian responses to dark pulses

Marilyn J. Duncan, Anthony W. Deveraux

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Aging involves many alterations in circadian rhythms, including a loss of sensitivity to both photic and nonphotic time signals. This study investigated the sensitivity of young and old hamsters to the phase advancing effect of a 6-h dark pulse on the locomotor activity rhythm. Each hamster was tested four times during a period of ~9 mo; periods of exposure to a 14-h photoperiod were alternated with the periods of exposure to constant light (20-80 lx), during which the dark pulses were administered. There was no significant difference in the phase shifts exhibited by the young (4-10 mo) and old hamsters (19-25 mo) or in the amount of wheel running activity displayed during each dark pulse. However, young hamsters had a significantly greater propensity to exhibit split rhythms immediately after the dark pulses. These results suggest that, although aging does not reduce the sensitivity of the circadian pacemaker to this nonphotic signal, it alters one property of the pacemaker, i.e., the flexibility of the coupling of its component oscillators.

Original languageEnglish
Pages (from-to)R586-R590
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume279
Issue number2 48-2
DOIs
StatePublished - 2000

Funding

FundersFunder number
National Institute on AgingR01AG013418

    Keywords

    • Circadian rhythms
    • Hamsters
    • Locomotor rhythms
    • Splitting

    ASJC Scopus subject areas

    • Physiology
    • Physiology (medical)

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