Side view of confocal projections from 2 (a, a’) and 3 (b, b’) dpf zebrafish embryos showing Neurogranin-like (Nrgn-like) immunoreaction (in green) and counterstained with Sytox Orange Nucleic Acid (in magenta). Arrowheads point to mesencephalic and rhombencephalic positive cell groups. A faintly labeled cell was also pointed in the optic tectum (arrow). Rostral is to the left and dorsal to the top. For abbreviations, see the list. Scale bars, 100 µm

Side (a, a’, c, c’) dorsal (b, b’) and ventral (d, d’) confocal projections of zebrafish brains from 5 (a), 5.5 (b) and 6 (c, d) dpf larvae showing Neurogranin-like (Nrgn) immunoreaction of zebrafish brain (in green) and counterstained with Sytox Orange Nucleic Acid (in magenta). Rostral is to the left. For abbreviations, see the list. Scale bars, 100 µm

a–n Photomicrographs of transverse sections showing Nrgn-like immunoreaction (in green) in the retina (a), brain (b–m) and spinal cord (n) of a 6 dpf zebrafish larvae. Section levels are indicated in the longitudinal schema of the brain at the bottom. In b, outlined stars show the olfactory glomeruli. Note in j the slightly mismatch between both sides of the brain at mesencephalic level. Arrows in k point to the CSF-contacting cell processes directed towards the posterior recess of the hypothalamus. Asterisk: ventricle. For abbreviations, see the list. Scale bars, 200 µm

Side view of confocal projections from 16 (a, a’) and 21 (b, b’) dpf zebrafish brains showing Nrgn-like immunoreaction (in green) and counterstained with Sytox Orange Nucleic Acid (in magenta). Rostral is to the left and dorsal to the top. For abbreviations, see the list. Scale bars, 100 µm