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Alterations in the circadian system in advanced age
1NSF Science and Technology Center for Biological Timing, Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208-3520, USA.
Ciba Foundation Symposium
|January 1, 1995
Summary
Aging impairs the circadian clock
Area of Science:
- Chronobiology
- Neuroscience
- Gerontology
Background:
- Circadian rhythms regulate daily physiological processes.
- Non-photic stimuli also influence circadian clock phase.
- Aging impacts circadian clock responses.
Purpose of the Study:
- Investigate age-related changes in circadian clock response to photic and non-photic stimuli.
- Explore the physiological basis of these age-related alterations.
- Identify potential mechanisms for restoring circadian function.
Main Methods:
- Studied old hamsters (>16 months) and young controls.
- Assessed responses to light pulses and activity-inducing stimuli.
- Examined effects of monoamine depletion and fetal tissue transplantation.
Main Results:
- Old hamsters showed altered entrainment, light response, and re-entrainment.
- Aging led to reduced responsiveness to non-photic stimuli.
- Monoamine depletion mimicked aging effects; fetal tissue partially reversed them.
Conclusions:
- Aging significantly alters circadian clock responsiveness to external stimuli.
- Monoaminergic pathways are implicated in age-related circadian dysfunction.
- Restoring circadian function may involve targeting these pathways or neural transplantation.
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