Figure 7. Respiratory role of GABA_B receptors.

A, decreases in respiratory frequency ∼15 min after bilateral microinjections of 25 mm CGP 35348 into the pTRG in one preparation. B, absence of appreciable respiratory effects ∼15 min after bilateral microinjections of 25 mm CGP 35348 into the region of vagal motoneurons (MN region) in a different preparation. The sites (pink area, pTRG; blue area, vagal MN region) where CGP 35348 (CGP) was microinjected are shown on a schematic illustration of a dorsal view of the lamprey mesencephalon–rhombencephalon. pTRG, paratrigeminal respiratory group; V, trigeminal motor nucleus; VII, facial motor nucleus; IX, glossopharyngeal motor nucleus; X, vagal motor nucleus; VA, raw vagal nerve activity; IVA, integrated vagal nerve activity.