Fig. 1.

Representative photomicrographs of level-matched coronal sections of the dentate gyrus from 12-month adult control (adult; a, d, g, j), 24-month-old control (old; b, e, h, k), and 24-month-old caloric-restricted (old + CR; c, f, i, l) rats. Sections shown in a, b, c were Nissl-stained, whereas d, e, f were immunostained for NPY, those shown in g, h, i were immunostained for SS and those shown in j, k, l were immunostained for VAChT. Note that there are no differences in the density of hilar cells in the Nissl-stained sections of the three groups. Note also that the density of NPY-IR and SS-IR cells and the density of VAChT-IR varicosities in the dentate hilus is decreased in the 24-month-old control rat when compared with the 12-month adult control rat, and conversely increased in 24-month-old caloric-restricted rat when compared to the 24-month-old control rat. There are no differences in the density of the NPY-IR and SS-IR cells and in the density of VAChT-IR varicosities between the 24-month-old caloric-restricted and the 12-month adult control rat. ML dentate gyrus molecular layer, GL granule cell layer, H dentate hilus, CA3 pyramidal cell layer of CA3 hippocampal field. Scale bar = 200 μm in A-I and 20 μm in j–l