Verification of SCN DCX immunoreactivity and comparative expression in the juvenile and adult rat. A-D. Photomicrographs of DCX-immunoreactivity and DAPI staining in the ventral hypothalamus of the rat brain. Brain sections were from either P25 (A-C) or adult (6 month, D) rats. Brain sections were incubated with either control (A, B, D) or neutralized (C) anti-DCX antibody. A-C. Immuno-neutralization blocks detection of DCX in the SCN. Note that the camera exposure time of image C was longer relative to that of image B in order to reveal some background fluorescence. D. Note that DCX immunoreactivity in the adult is similarly distributed in the SCN, but at a lower relative level compared with the PN25 sample. Scale bar = 100 μm. Abbreviations: 3V, third ventricle; OC, optic chiasm. E. Absence of rhythmic DCX expression in the adult SCN. Histogram showing levels of DCX immunoreactivity at three rostro-caudal brain levels (-0.48, -0.72, -0.96 mm from bregma) measured at four time points. Levels (Leica Qwin Mean Grey level) are the mean ± S.E.M of six measurements (2 samples of SCN from each of 3 rats). Statistical analysis (ANOVA; see text) revealed no significant changes across time.