TY - JOUR
T1 - Pressure-volume behaviour of the rat upper airway
T2 - Effects of tongue muscle activation
AU - Bailey, E. Fiona
AU - Fregosi, Ralph R.
PY - 2003/4/15
Y1 - 2003/4/15
N2 - Our hypothesis was that the simultaneous activation of tongue protrudor and retractor muscles (co-activation) would constrict and stiffen the pharyngeal airway more than the independent activation of tongue protrudor muscles. Upper airway stiffness was determined by injecting known volumes of air into the sealed pharyngeal airway of the anaesthetized rat while measuring nasal pressure under control (no-stimulus) and stimulus conditions (volume paired with hypoglossal (XII) nerve stimulation). Stimulation of the whole XII nerves (co-activation) or the medial XII branches (protrudor activation) effected similar increases in total pharyngeal airway stiffness. Importantly, co-activation produced volume compression (airway narrowing) at large airway volumes (P < 0.05), but had no effect on airway dimension at low airway volumes. In comparison, protrudor activation resulted in significant volume expansion (airway dilatation) at low airway volumes and airway narrowing at high airway volumes (P < 0.05). In conclusion, both co-activation and independent protrudor muscle activation increase airway stiffness. However, their effects on airway size are complex and depend on the condition of the airway at the time of activation.
AB - Our hypothesis was that the simultaneous activation of tongue protrudor and retractor muscles (co-activation) would constrict and stiffen the pharyngeal airway more than the independent activation of tongue protrudor muscles. Upper airway stiffness was determined by injecting known volumes of air into the sealed pharyngeal airway of the anaesthetized rat while measuring nasal pressure under control (no-stimulus) and stimulus conditions (volume paired with hypoglossal (XII) nerve stimulation). Stimulation of the whole XII nerves (co-activation) or the medial XII branches (protrudor activation) effected similar increases in total pharyngeal airway stiffness. Importantly, co-activation produced volume compression (airway narrowing) at large airway volumes (P < 0.05), but had no effect on airway dimension at low airway volumes. In comparison, protrudor activation resulted in significant volume expansion (airway dilatation) at low airway volumes and airway narrowing at high airway volumes (P < 0.05). In conclusion, both co-activation and independent protrudor muscle activation increase airway stiffness. However, their effects on airway size are complex and depend on the condition of the airway at the time of activation.
UR - http://www.scopus.com/inward/record.url?scp=0038745493&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0038745493&partnerID=8YFLogxK
U2 - 10.1113/jphysiol.2002.029298
DO - 10.1113/jphysiol.2002.029298
M3 - Article
C2 - 12640023
AN - SCOPUS:0038745493
SN - 0022-3751
VL - 548
SP - 563
EP - 568
JO - Journal of Physiology
JF - Journal of Physiology
IS - 2
ER -