Figure 4. Photomicrograph of a representative transverse section of the medulla oblongata showing the sites of a bilateral microinjection of suramin into the NTS of a WHBP.

All effective sites were confined to the commissural NTS and marked with Pontamine Sky Blue. The dark staining of neuronal somata by this dye is mainly confined to the NTS with some spread into the gracile nuclei (GN). Other abbreviations: CC, central canal; X, dorsal vagal motor nucleus; XII, hypoglossal motor nucleus.