TY - JOUR
T1 - Control of nasal dilator muscle activities during exercise
T2 - Role of nasopharyngeal afferents
AU - Sullivan, Jenna
AU - Fuller, David
AU - Fregosi, Ralph F.
PY - 1996/5
Y1 - 1996/5
N2 - Our primary aim was to determine whether reducing the activity of nasal airway receptors would influence drive to the nasal dilator muscles (NDMs) during exercise. We used lidocaine (2%) or nasal splints to diminish afferent airway receptor activity and measured the electromyogram (EMG) activity of the NDMs during incremental bicycle exercise in subjects who breathed nasally. NDM EMG activities increased as a function of exercise intensity but were not changed by lidocaine and were only slightly reduced by splinting. Similarly, neither intervention altered the normal decrease in NDM EMG activity associated with reductions in airway resistance evoked by He-O2 breathing. We also compared the NDM EMG response to exercise with that evoked by CO2 rebreathing at rest to determine whether the nature of the ventilatory stimulus influences drive to the NDMs; comparisons were made at constant levels of nasal inspired ventilation and, therefore, constant total ventilatory output. The increase in EMG activity was much higher during exercise compared with hyperoxic hypercapnia. In conclusion, 1) desensitizing the nasal airway does not alter NDM activity significantly during exercise and 2) exercise results in much greater increases in NDM activity compared with hypercapnia, indicating that different ventilatory stimuli can evoke more or less activation of upper airway motoneurons, even when comparisons are made at constant levels of total ventilatory output.
AB - Our primary aim was to determine whether reducing the activity of nasal airway receptors would influence drive to the nasal dilator muscles (NDMs) during exercise. We used lidocaine (2%) or nasal splints to diminish afferent airway receptor activity and measured the electromyogram (EMG) activity of the NDMs during incremental bicycle exercise in subjects who breathed nasally. NDM EMG activities increased as a function of exercise intensity but were not changed by lidocaine and were only slightly reduced by splinting. Similarly, neither intervention altered the normal decrease in NDM EMG activity associated with reductions in airway resistance evoked by He-O2 breathing. We also compared the NDM EMG response to exercise with that evoked by CO2 rebreathing at rest to determine whether the nature of the ventilatory stimulus influences drive to the NDMs; comparisons were made at constant levels of nasal inspired ventilation and, therefore, constant total ventilatory output. The increase in EMG activity was much higher during exercise compared with hyperoxic hypercapnia. In conclusion, 1) desensitizing the nasal airway does not alter NDM activity significantly during exercise and 2) exercise results in much greater increases in NDM activity compared with hypercapnia, indicating that different ventilatory stimuli can evoke more or less activation of upper airway motoneurons, even when comparisons are made at constant levels of total ventilatory output.
KW - carbon dioxide rebreathing
KW - control of breathing
KW - facial motoneurons
KW - lidocaine
KW - nasal splints
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U2 - 10.1152/jappl.1996.80.5.1520
DO - 10.1152/jappl.1996.80.5.1520
M3 - Article
C2 - 8727535
AN - SCOPUS:0029913739
SN - 8750-7587
VL - 80
SP - 1520
EP - 1527
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -