Abstract
Rationale: Historically, respiratory-related research in sleep apnea has focused exclusively on the extrinsic tongue muscles (i.e., genioglossus, hyoglossus, and styloglossus). Until recently, the respiratory control and function of intrinsic tongue muscles (i.e., inferior and superior longitudinals, transverses, and verticalis), which comprise the bulk of the tongue, were unknown. Objectives: The current study sought to determine if extrinsic and intrinsic tongue muscles are coactivated in conditions of hypoxemia comparable to that experienced by adults with obstructive sleep apnea. Measurements: Esophageal pressure and EMG activity of an extrinsic (hyoglossus) and an intrinsic (superior longitudinal) tongue muscle were studied in anesthetized, tracheotomized, spontaneously breathing rats. Average EMG activity was compared in a control gas condition (Pao2, 160 ± 12 mm Hg) and in mild isocapnic hypoxia (Pao2, 69 ± 7.2 mm Hg), with and without brief (3-breath) airway occlusions, pre- and postbilateral vagotomy. Main Results: (1) intrinsic and extrinsic tongue muscles are coactivated in mild hypoxia, (2) airway occlusion increased the activities of intrinsic retractor muscles in mild hypoxia, and (3) extrinsic retractor muscles have a steeper rate of rise of activity and an earlier burst onset relative to intrinsic retractor activities in mild hypoxia. Conclusions: These findings support our working hypothesis that airway patency is maintained not simply by activation of extrinsic tongue muscles but by the coactivation of intrinsic and extrinsic protrudor and retractor muscles.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1403-1407 |
| Number of pages | 5 |
| Journal | American Journal of Respiratory and Critical Care Medicine |
| Volume | 171 |
| Issue number | 12 |
| DOIs | |
| State | Published - Jun 15 2005 |
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Keywords
- EMG
- Hypoxia
- Sleep apnea
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
Cite this
Po2-dependent changes in intrinsic and extrinsic tongue muscle activities in the rat. / Bailey, Elizabeth F; Janssen, Patrick L.; Fregosi, Ralph F.
In: American Journal of Respiratory and Critical Care Medicine, Vol. 171, No. 12, 15.06.2005, p. 1403-1407.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Po2-dependent changes in intrinsic and extrinsic tongue muscle activities in the rat
AU - Bailey, Elizabeth F
AU - Janssen, Patrick L.
AU - Fregosi, Ralph F
PY - 2005/6/15
Y1 - 2005/6/15
N2 - Rationale: Historically, respiratory-related research in sleep apnea has focused exclusively on the extrinsic tongue muscles (i.e., genioglossus, hyoglossus, and styloglossus). Until recently, the respiratory control and function of intrinsic tongue muscles (i.e., inferior and superior longitudinals, transverses, and verticalis), which comprise the bulk of the tongue, were unknown. Objectives: The current study sought to determine if extrinsic and intrinsic tongue muscles are coactivated in conditions of hypoxemia comparable to that experienced by adults with obstructive sleep apnea. Measurements: Esophageal pressure and EMG activity of an extrinsic (hyoglossus) and an intrinsic (superior longitudinal) tongue muscle were studied in anesthetized, tracheotomized, spontaneously breathing rats. Average EMG activity was compared in a control gas condition (Pao2, 160 ± 12 mm Hg) and in mild isocapnic hypoxia (Pao2, 69 ± 7.2 mm Hg), with and without brief (3-breath) airway occlusions, pre- and postbilateral vagotomy. Main Results: (1) intrinsic and extrinsic tongue muscles are coactivated in mild hypoxia, (2) airway occlusion increased the activities of intrinsic retractor muscles in mild hypoxia, and (3) extrinsic retractor muscles have a steeper rate of rise of activity and an earlier burst onset relative to intrinsic retractor activities in mild hypoxia. Conclusions: These findings support our working hypothesis that airway patency is maintained not simply by activation of extrinsic tongue muscles but by the coactivation of intrinsic and extrinsic protrudor and retractor muscles.
AB - Rationale: Historically, respiratory-related research in sleep apnea has focused exclusively on the extrinsic tongue muscles (i.e., genioglossus, hyoglossus, and styloglossus). Until recently, the respiratory control and function of intrinsic tongue muscles (i.e., inferior and superior longitudinals, transverses, and verticalis), which comprise the bulk of the tongue, were unknown. Objectives: The current study sought to determine if extrinsic and intrinsic tongue muscles are coactivated in conditions of hypoxemia comparable to that experienced by adults with obstructive sleep apnea. Measurements: Esophageal pressure and EMG activity of an extrinsic (hyoglossus) and an intrinsic (superior longitudinal) tongue muscle were studied in anesthetized, tracheotomized, spontaneously breathing rats. Average EMG activity was compared in a control gas condition (Pao2, 160 ± 12 mm Hg) and in mild isocapnic hypoxia (Pao2, 69 ± 7.2 mm Hg), with and without brief (3-breath) airway occlusions, pre- and postbilateral vagotomy. Main Results: (1) intrinsic and extrinsic tongue muscles are coactivated in mild hypoxia, (2) airway occlusion increased the activities of intrinsic retractor muscles in mild hypoxia, and (3) extrinsic retractor muscles have a steeper rate of rise of activity and an earlier burst onset relative to intrinsic retractor activities in mild hypoxia. Conclusions: These findings support our working hypothesis that airway patency is maintained not simply by activation of extrinsic tongue muscles but by the coactivation of intrinsic and extrinsic protrudor and retractor muscles.
KW - EMG
KW - Hypoxia
KW - Sleep apnea
UR - http://www.scopus.com/inward/record.url?scp=20444391317&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=20444391317&partnerID=8YFLogxK
U2 - 10.1164/rccm.200411-1550OC
DO - 10.1164/rccm.200411-1550OC
M3 - Article
C2 - 15778485
AN - SCOPUS:20444391317
VL - 171
SP - 1403
EP - 1407
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
SN - 1073-449X
IS - 12
ER -