Anesthetic effects on phasic genioglossus activity and the negative pressure reflex in the rat

Abstract

The genioglossus muscle (GG) is an upper airway dilator which protects pharyngeal patency in humans. General anesthesia typically impairs airway stability and decreases phasic GG EMG in vagotomized, ventilated rats. However, some anesthetics may increase GG EMG in spontaneously‐breathing rats. The mechanisms by which anesthetics affect GG activity have not been studied systematically. The ED50 for pentobarbital, propofol, or isoflurane was estimated in 63 rats. After tracheostomy to isolate the upper airway, phasic GG EMG and responses to upper airway negative pressure (NPR) were measured with and without blood pressure or end‐tidal CO2 normalized, and also in vagotomized or Kolliker‐Fuse nu..