Figure 4. High frequency stimulation of the ATN increases the mitotic activity of ANPs.

A: The number of QNPs immunostained for BrdU⁺ did not change in any experimental group.

B: The number of ANPs immunostained for BrdU was significantly increased in the HF animals, demonstrating that they are proliferating more whereas the mitotic activity of the QNPs did not change.

C-L: Representative confocal microscopy images from DG sections of LF (C-G), and HF (H-L) animals. Anti-BrdU staining is shown in magenta (D,I), and anti-CFP staining is shown in green (E,J); the overlap is seen as yellow in (F,K). Anti-GFAP staining, to distinguish between the QNPs (arrows in C,H) and the ANPs is shown in blue (G,L). In the image from the HF animal, higher numbers of BrdU⁺, ANPs, and BrdU⁺ANPs as compared to the LF animals, are evident.

M,N: The relative proportion of BrdU⁺QNPs within the QNP population (n) or BrdU⁺ANPs within the ANP population were not altered in any group.

O,P: The relative proportion of BrdU⁺QNPs within the population of BrdU⁺ cells was significantly decreased in the HF as compared to the NF and LF groups (P); the decrease is due to the increase in BrdU⁺ cells as the number of QNPs remains constant. The relative proportion of BrdU⁺ANPs within the ANP population, however, was not affected by stimulation of the ATN (P). Data are shown as mean±s.e.m (n=5 mice for the NF group and 6 for LF and HF groups). **p<0.005, ***p<0.001. Scale bars are 10μm.