Effect of salicylate on upper airway dilating muscles in anesthetized dogs

It is well documented that salicylate given in large doses stimulates ventilation. As increased ventilatory drive is often associated with augmented upper airway dilating muscle activity, we evaluated in anesthetized dogs the effect of salicylate on the electrical activity of three upper airway muscles, the alae nasi, the genioglossus, and the posterior cricoarytenoid. The electromyograms of these muscles were compared with those of the diaphragm before and at 15-min intervals after intravenous salicylate administration (250 mg/kg). Salicylate induced a gradual increase in ventilation and in the electrical activity of all muscles examined (p less than 0.001). Compared to baseline activity, salicylate increased the electrical activity of the genioglossus more than that of the diaphragm (p less than 0.01). The increase in upper airway muscle activity was observed also in vagotomized dogs, and was not accounted for by changes in arterial blood gases or pH. Increases in upper airway muscle electrical activity were associated with a significant decrease in upper airway resistance to airflow (mean reduction of 62 +/- 7% SE, p less than 0.01). The preferential increase in genioglossus electrical activity and the decrease in upper airway resistance observed in this study with salicylate suggest that salicylate, and possibly other pharmacologic agents that stimulate ventilation, may improve upper airway patency.