Ischemic preconditioning affords neuroprotection against ischemia-induced neuronal death. Toluidine blue-stained coronal brain sections at the level of the dorsal hippocampus from sham (n = 8; a, b) and experimental rats subjected to ischemic preconditioning (n = 8; c, d), global ischemia (n = 8; e, f) or to preconditioning, followed by global ischemia (n = 8; g, h) at 7 d after reperfusion. Preconditioning did not induce neuronal death (c, d). Global ischemia induced loss of pyramidal neurons in the hippocampal CA1; cell loss was not detected in CA3 or dentate gyrus (e, f). Preconditioning afforded robust neuroprotection against subsequent global ischemia-induced death (g, h). so, Stratum oriens; sp, stratum pyramidale; sr, stratum radiatum. Scale bars: a, c, e, g, 500μm; b, d, f, h, 50μm. Quantitation of photomicrographs like those shown in a–h (i). *p < 0.05; **p < 0.01.