Fig. 5. Distribution of Trypan Blue in the brain of SW eel (left) and corresponding cross-sectional planes (right). Trypan Blue signal (stained strong red color) was detected in (A) the pineal gland (P) and saccus dorsalis (SD); (B) magnocellular part of preoptic nucleus (PM); (C) area postrema (AP) of medulla oblongata. Approximate areas photographed are indicated by broken squares drawn in cross-sectional planes. Magnified views are shown in the boxed areas at left-bottom of B and C. Locations of cross sectional planes are shown in Fig. 1. PP, parvocellular part of preoptic nucleus; NCC, commissural nucleus of Cajal; GVC, glossopharyngeal-vagal motor complex; NSO, spino-occipital motor nucleus; RF, reticular formation. Scale bars, 20 µm.