Figure 6. Modulation of rhythmic breathing and genioglossus muscle amplitude by SST and SST₂ receptors in anesthetized rats.

Microperfusion of SST (200 μM) into the preBötC (a) depressed rhythmic breathing and genioglossus muscle amplitude (b), reduction that were blocked by the SST₂ receptor antagonist CYN-154806 (20 μM, b). Dots indicate breathing rate for each breath. The microperfusion probe was located ventral to the nucleus ambiguus in the preBötC region (c). SST decreased breathing rate (n = 5, d) and CYN-154806 blocked the inhibition by SST. Diaphragm muscle amplitude was not changed by SST or CYN-154806 (e). SST also diminished significantly genioglossus muscle amplitude and this decrease was not blocked by the SST₂ receptor antagonist (f). *Indicate mean values significantly different from aCSF/baseline with P < 0.05. Data are indicated as means ± S.E.M and as individual values for each animal. SST, somatostatin. CYN, the SST_2A antagonist CYN-154806.