Figure 5.

The number and spatial distribution of GAD67-GFP/GIN-expressing neurons in the barrel cortex of SERT^GluΔ mice. (A) Representative images of GFP-expressing neurons in tangential sections of the PMBSF from SERT^GluΔ and control littermate mice at indicated ages. Barrels in arcs 1–3 of rows B-D are indicated in the P7 cortex. Boundaries between barrels are blurred (arrows) in SERT^GluΔ mice at P7 as well as at P16 and P30, while the gross barrel architecture is preserved. (B-C) Quantification of the number of GFP+ neurons and their distribution in nine barrels of arcs 1–3 of rows B-D of the PMBSF. (B) Significant reduction in the number of GFP+ neurons in one- and two-month-old SERT^GluΔ mice as compared to control littermates. The numbers of GFP+ neurons at earlier developmental stages were comparable between the two genotypes. (C) Evaluation of the spatial distribution of GFP+ neurons in the barrels, by quantifying the ratio of GFP+ neurons in the barrel walls relative to that in the barrel hollows in SERT^GluΔ and control mice. For each time point, serial sections through the PMBSF from SERT^GluΔ and control littermates were processed and analyzed in parallel. Data represent mean per 50 μm section ± SEM, N = 4–6 mice per age per genotype per time point, and P values are based on t-tests. (D-E) Assessing apoptosis by TUNEL assay. (D) Quantifying the total number of TUNEL+ cells in arcs 1–3 of rows B-D in serial tangential sections through the PMBSF. N = 5 mice for each genotype per time point. Data represent mean ± SEM, t-tests. (E) Representative images showing TUNEL in a GFP+ neuron located in the barrel cortex at P30. Left corner insets show confocal images of the labeled cell indicated by a yellow arrow. The TUNEL+ cell body was smaller, compared to other GFP+ cell bodies in the same brain section, presumably due to shrinking of the dying cell.