Neural Control of the Upper Airway: Integrative Physiological Mechanisms and Relevance for Sleep Disordered Breathing

Abstract

The various neural mechanisms affecting the control of the upper airway muscles are discussed in this review, with particular emphasis on structure-function relationships and integrative physiological motor-control processes. Particular foci of attention include the respiratory function of the upper airway muscles, and the various reflex mechanisms underlying their control, specifically the reflex responses to changes in airway pressure, reflexes from pulmonary receptors, chemoreceptor and baroreceptor reflexes, and postural effects on upper airway motor control. This article also addresses the determinants of upper airway collapsibility and the influence of neural drive to the upper airway muscles, and the influence of common drugs such as ethanol, sedative hypnotics, and opioids on upper airway motor control. In addition to an examination of these basic physiological mechanisms, consideration is given throughout this review as to how these mechanisms relate to integrative function in the intact normal upper airway in wakefulness and sleep, and how they may be involved in the pathogenesis of clinical problems such obstructive sleep apnea hypopnea.

Nose and Sleep Breathing Disorders

“…In the respiratory model based on a Starling resistor, the nose is a key determinant of upper airway resistance ( Fig. 23.2 ) (Farre et al 2008 ;Horner 2012 ). Nasal pressure ( P N ) is zero (atmosphere reference value) in normal conditions.…”

Effects of targeted activation of tongue muscles on oropharyngeal patency in the rat

“…One such disease, obstructive sleep apnea (OSA), involves airway blockage consequent to reduced lingual muscle tone likely associated with inadequate neural activation normally provided by the hypoglossal nerve (HGN) [1]. Previous attempts to stimulate lingual muscles with intramuscular electrodes to increase tone [2][3][4][5][6][7] or to stimulate the HGN [8][9][10][11][12], resulted in promising but variable results.…”

“…Selective stimulation of the HGN enlarges the oropharyngeal airway: Eight contacts(1)(2)(3)(4)(5)(6)(7)(8) applied to the ventral half of the right HGN were successively activated (A). B: Increases in the oropharyngeal airway diameter, measured from endoscopic images as the area bordered by the pharynx, tongue base, and pharyngeal walls, were normalized relative to their unstimulated values (U, black bars).…”

Neural Control of the Upper Airway: Respiratory and State‐Dependent Mechanisms

“…Therefore, neurophysiological and neuropharmacological studies of activity in respiratory motoneurons that innervate upper airway muscles, central respiratory neurons, and behavioral state-controlling neurons are a major focus of this article. Complementary topics pertaining to the neuromechanical basis of OSA and its clinical and translational aspects have been reviewed in other recent overview articles (100, 206, 207, 586). …”