Fig. 5. Variations in patterns of Bcl-2 immunostaining in the hippocampus of juvenile (A, B, E) and adult squirrel monkeys (C, D, F). At this level, Bcl-2 immunoreactivity is largely confined to perikarya of granule cell layer and neuropil of the molecular layer, leaving the polymorph layer relatively free of immunostaining. A, B, In juvenile monkeys, the granule cell layer is thin, and the neuropil of the molecular layer is moderately stained. C, D, In adult monkeys, the granular layer is thicker, and the immunostaining in certain sectors of the molecular layer is more intense than in juveniles. E, F, High-power views of similarly intense immunoreactive neurons in the granular layer in juveniles (E) and in adult (F) monkeys. CA2,CA3, Fields 2 and 3, respectively, of Ammon’s horn (cornu ammonis); DG, dentate gyrus with its molecular (M), granular (G), and polymorph (P) layers. Scale bars: A, C, 500 μm; B, D, 200 μm; E, F, 100 μm.