Transmission electron micrographs of ultrathin sections showing the surface of olfactory epithelium adult zebrafish: (a) ci, ONR ciliated; mv, ONR microvillous; sc, supporting cells; bc, basal cells; bl, basal lamina. (b) ci, ONR ciliated; n,“checkerboard” nucleus of ciONR; K, kinocilia; mv, ONR microvillous; sc, supporting cells; kinocilium basal body foot (arrowhead), junctional complex with neighboring supporting cells (arrows). (c) cn, crypt neurons with several cilia within the crypt (star); special supporting cells (*).

Olfactory lamellae of zebrafish larvae 5dpf, cross view. (a–c) Immunohistochemical detection (immunofluorescence method) of pro-BDNF and S100 protein. (d–f) Immunohistochemical detection (immunofluorescence method) of pro-BDNF and calretinin (CR). Subpopulation of olfactory epithelium sensory cells with an elongated shape showing immunoreactivity to (a,d) pro-BDNF, (b) S100 protein, and (e) calretinin. (c,f). Colocalization view. Magnification, 63×. Scale bar, 5 µm.

Olfactory lamellae of adult zebrafish, dorsal view. Immunohistochemical detection of BDNF: (a,b) peroxidase method, (c,d) immunofluorescence method. (a–d) Elongated sensory cells in sensory segment of olfactory lamellae show immunoreactivity to BDNF. (a,c) Scale bar 50 µm. (b,d) Scale bar 5 µm.

Olfactory lamellae of adult zebrafish, dorsal view. (a–c) Immunohistochemical detection (immunofluorescence method) of BDNF and calretinin. (d–f) Immunohistochemical detection (immunofluorescence method) of S100 protein. Ciliated sensory olfactory neurons in sensory segment of olfactory lamellae showing immunoreactivity to (a) BDNF and (b) calretinin. (c) Colocalization view (d–f). Crypt olfactory neurons showing immunoreactivity to S100 protein. Scale bar (a–d) 50 µm and (e,f) 5 µm.

Light micrographs (hematoxylin/eosin staining) of adult zebrafish taste buds, dorsal view. (a) Oral cavity with taste buds, taste buds of the lips (*). (a,b)Taste buds showing light cells (arrowhead) add dark cells (arrow); (b) Merkel-like basal cells (star). Scale bar (a) 200 µm and (b,c) 50 µm.

Cutaneous taste buds: (a–c) zebrafish larvae (5 dpf); (d–i) adult zebrafish, transversal view. (a–c) Immunohistochemical detection (immunofluorescence method) of pro-BDNF and calretinin. (d–i) Immunohistochemical detection (immunofluorescence method) of BDNF and calretinin. (a–c) Cytoplasmatic immunoreactivity for pro-BDNF and calretinin in sensory cells of cutaneous taste buds of zebrafish larvae (5 dpf). (d–i) Sensory cells of cutaneous taste buds of adult zebrafish showing immunopositivity to BDNF and calretinin. (c,f,i) Colocalization view. Scale bar, 5 µm.

Oral taste buds: (a–f) zebrafish larvae (5 dpf); (g–i) adult zebrafish, transversal view. Immunohistochemical detection (immunofluorescence method) of (a–f) pro-BDNF and calretinin and (g–i) BDNF and dalretinin. Subpopulation of sensory cells that might be identified as light cells showing immunopositivity to (a,d) pro-BDNF and (b,e) calretinin. (g) BDNF in light sensory cells and (h) calretinin in dark sensory cells. (c,f,i) Colocalization view. Scale bar, 5 µm.

Oral taste buds: (a–f) zebrafish larvae (5 dpf); (g–i) adult zebrafish, transversal view. Immunohistochemical detection (immunofluorescence method) of (a–f) pro-BDNF and calretinin and (g–i) BDNF and dalretinin. Subpopulation of sensory cells that might be identified as light cells showing immunopositivity to (a,d) pro-BDNF and (b,e) calretinin. (g) BDNF in light sensory cells and (h) calretinin in dark sensory cells. (c,f,i) Colocalization view. Scale bar, 5 µm.

ICCC of adult zebrafish, dorsal view. Immunohistochemical detection of BDNF: (a,b) peroxidase method; (c,d) immunofluorescence method. (a–d) ICCC immunoreactivity to BDNF. Scale bar, 5 µm.