Fig. 2.

The number of BrdU-positive cells in the adult hippocampus is increased after chronic antidepressant treatment. Rats received injections of BrdU 4 d after the last ECS (10 d) or drug (14–21 d) treatment and were killed 24 hr after the last BrdU injection. Shown are representative photomicrographs (10× magnification) from vehicle (A), tranylcypromine (B), ECS (C), or fluoxetine (D). The majority of the BrdU-labeled cells are located in the subgranular zone (SGZ, indicated byarrow in A) of the hippocampus, the region between the granule cell layer (GCL) and hilus (H).