Fig. 4. Influence of vagal nerve section on genioglossus activity and breathing.  Open circles = vagal nerves intact;  diamonds = vagotomized rats. Data are mean ± SEM. *  P < 0.05 for dose effects of isoflurane (within groups). #  P < 0.05  versus controls (between-subjects effects). (  A ) Phasic genioglossus activity. At 1% isoflurane, phasic genioglossus activity was significantly higher in vagotomized rats compared with controls. Isoflurane increased genioglossus activity dose dependently in controls, whereas it decreased it in vagotomized rats. (  B) Flow rate. At 1% isoflurane, flow rate was significantly higher in vagotomized rat compared with controls.