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Aging increases upper airway collapsibility in Fischer 344 rats
Andrew D Ray1, Toshiyuki Ogasa, Ulysses J Magalang
1Center for Research and Education in Special Environments, State University of New York at Buffalo, 515 Kimball Tower, 3435 Main St., Buffalo, NY 14214, USA. adr@buffalo.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 30, 2008
Summary
Older rats have more collapsible upper airways, a change linked to aging and neural control, not muscle structure. This impacts breathing and may explain age-related sleep-disordered breathing.
Area of Science:
- Physiology
- Aging Research
- Sleep Medicine
Background:
- Upper airway muscles are crucial for preventing airway collapse.
- Sleep-disordered breathing incidence rises with age.
- Age-related changes in muscle mechanics may increase airway collapsibility.
Purpose of the Study:
- To investigate the link between aging, upper airway muscle function, and airway collapsibility.
- To determine if age-related changes in muscle structure or neural control affect airway collapsibility.
Main Methods:
- Compared pharyngeal pressure (Pcrit) in young and old Fischer 344 rats.
- Measured Pcrit with intact hypoglossal (cnXII) nerve, after denervation, and during cnXII stimulation.
- Analyzed myosin heavy chain composition in genioglossus and sternohyoid muscles.
Main Results:
- Older rats exhibited significantly more collapsible upper airways (higher Pcrit) than younger rats.
- Hypoglossal nerve denervation increased collapsibility in both age groups.
- Hypoglossal nerve stimulation decreased collapsibility in both age groups.
- Age-related shifts in myosin heavy chain isoforms were observed in specific muscles.
Conclusions:
- Upper airway collapsibility increases with age.
- This age-related increase is primarily associated with altered neural control of upper airway muscles, rather than intrinsic muscle structural changes.
- Findings suggest a mechanism for increased sleep-disordered breathing in older individuals.
