Control of Genioglossus Muscle by Sleep State-Dependent Neuromodulators

  • Richard L. Horner
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 605)

Pharyngeal muscle tone decreases in sleep and this predisposes some individuals to obstructive sleep apnea. This review summarizes the control of the genioglossus muscle by sleep-state dependent neuromodulators at the hypoglossal motor nucleus, the source of motor output to the genioglossus muscle of the tongue. Knowledge of such mechanisms is relevant to identifying and developing new strategies to augment pharyngeal muscle activity in sleep, potentially as treatments for obstructive sleep apnea.


Obstructive Sleep Apnea Obstructive Sleep Apnea Patient Genioglossus Muscle Respiratory Muscle Activity Hypoglossal Motor 


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  1. Aoki, C.R., Liu, H., Downey, G.P., Mitchell, J. and Horner, R.L. (2006) Cyclic nucleotides modulate genioglossus and hypoglossal responses to excitatory inputs in rats. Am. J. Respir. Crit. Care Med. 173, 555–565.CrossRefPubMedGoogle Scholar
  2. Chan, E., Steenland, H.W., Liu, H. and Horner, R.L. (2006) Endogenous excitatory drive modulating respiratory muscle activity across sleep-wake states. Am. J. Respir. Crit. Care Med. [E-pub ahead of print].Google Scholar
  3. Chase, M.H. and Morales, F.R. (2000) Control of motoneurons during sleep. In: M.H. Kryger, T. Roth and W.C. Dement (Eds.), Principles and Practice of Sleep Medicine. W.B. Saunders, Philadelphia, pp. 155–168.Google Scholar
  4. Feldman, J.L., Neverova, N.V. and Saywell, S.A. (2005) Modulation of hypoglossal motoneuron excitability by intracellular signal transduction cascades. Resp. Physiol. Neurobiol. 147, 131–143.CrossRefGoogle Scholar
  5. Fenik, V.B., Davies, R.O. and Kubin, L. (2005) REM sleep-like atonia of hypoglossal (XII) motoneurons is caused by loss of noradrenergic and serotonergic inputs. Am. J. Respir. Crit. Care Med. 172, 1322–1330.CrossRefPubMedGoogle Scholar
  6. Horner, R. L. (1996) Motor control of the pharyngeal musculature and implications for the pathogenesis of obstructive sleep apnea. Sleep 19, 827–853.PubMedGoogle Scholar
  7. Horner, R. L. (2001) The neuropharmacology of upper airway motor control in the awake and asleep states: implications for obstructive sleep apnoea. Resp. Res. 2, 286–294.CrossRefGoogle Scholar
  8. Jelev, A., Sood, S., Liu, H., Nolan, P. and Horner, R.L. (2001) Microdialysis perfusion of 5-HT into hypoglossal motor nucleus differentially modulates genioglossus activity across natural sleep-wake states in rats. J. Physiol. 532, 467–481.CrossRefPubMedGoogle Scholar
  9. Kubin, L., Davies, R.O. and Pack, L. (1998) Control of upper airway motoneurons during REM sleep. News Physiol. Sci. 13, 637–656.Google Scholar
  10. Liu, X., Sood, S., Liu, H. and Horner, R.L. (2005) Opposing muscarinic and nicotinic modulation of hypoglossal motor output to genioglossus muscle in rats in vivo. J. Physiol. 565, 965–980.CrossRefPubMedGoogle Scholar
  11. Morrison, J.L., Sood, S., Liu, H., Park, E., Nolan, P. and Horner, R.L. (2003a) GABA-A receptor antagonism at the hypoglossal motor nucleus increases genioglossus muscle activity in NREM but not REM sleep. J. Physiol. 548, 569–583.CrossRefPubMedGoogle Scholar
  12. Morrison, J.L., Sood, S., Liu, H., Park, E., Nolan, P. and Horner, R.L. (2003b) Role of inhibitory amino acids in control of hypoglossal motor outflow to genioglossus muscle in naturally sleeping rats. J. Physiol. 552, 975–991.CrossRefPubMedGoogle Scholar
  13. Sood, S., Liu, X., Liu, H., Nolan, P. and Horner, R.L. (2003) 5-HT at hypoglossal motor nucleus and respiratory control of genioglossus muscle in anesthetized rats. Resp. Physiol. Neurobiol. 138, 205–221.CrossRefGoogle Scholar
  14. Sood, S., Morrison, J.L., Liu, H. and Horner, R.L. (2005) Role of endogenous serotonin in modulating genioglossus muscle activity in awake and sleeping rats. Am. J. Respir. Crit. Care Med. 172, 1338–1347.CrossRefPubMedGoogle Scholar
  15. Sood, S., Raddatz, E., Liu, X., Liu, H. and Horner, R.L. (2006) Inhibition of serotonergic medullary raphe obscurus neurons suppresses genioglossus and diaphragm activities in anesthetized but not conscious rats. J. Appl. Physiol. 100, 1807–1821.CrossRefPubMedGoogle Scholar

Copyright information

© Springer 2008

Authors and Affiliations

  • Richard L. Horner
    • 1
  1. 1.Departments of Medicine and PhysiologyUniversity of TorontoTorontoCanada

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