Fig. 3.

Changes in the PAPs in vivo are in synchrony with changes in identified physiological glutamatergic activity. (A and B) Ezrin immunocytochemistry in hamster brain sections at the level of the SCN (dashed line). (A) Only the ependyma of the third ventricle (III.) and the midline tanycytes are labeled at 2 h before onset of the animal's nocturnal activity (ZT, 10 h). (B) Two hours after start of nocturnal activity (ZT, 14 h) in the dark, the PAPs in the SCN are selectively labeled in the characteristically diffuse pattern. (C) This effect is significant as quantified by densitometry (P < 0,002, paired Student's t test). Each data point represents the mean values from seven (ZT14, filled squares) or six animals (ZT10, open circles). The entire experiment was repeated twice with three or four animals per group, yielding similar and significant results. (Scale bars: 200 μm.)