Following a previously described method [20 (link),21 (link)], Bax, Bcl-2, and cytochrome c expression was measured by western blot analysis. Using protein lysis buffer, hippocampal samples were lysed and a colorimetric protein assay kit was used to detect protein concentrations (Bio-Rad, Hercules, CA, USA). After 30 μg of protein was separated on sodium dodecyl sulfate-polyacrylamide gels, the separated protein was transferred onto a nitrocellulose membrane (Schleicher & Schuell GmbH, Dassel, Germany). Anti-mouse β-actin antibody (1:1,000; Santa Cruz Biotechnology), anti-rabbit Bax antibody (Cell signaling Technology; 1:1,000), anti-mouse Bcl-2 antibody (1:1,000; Santa Cruz Biotechnology), and anti-rabbit cytochrome c antibody (1:1,000; Cell signaling Technology) were used as the primary antibodies. The secondary antibodies were horseradish peroxidase–conjugated anti-mouse antibodies (1:3,000; Vector Laboratories) for β-actin and Bcl-2, and horseradish peroxidase–conjugated anti-rabbit antibodies (1:5,000; Vector Laboratories) for Bax and cytochrome c. An enhanced chemiluminescence detection system (Amersham Pharmacia Biotech GmbH, Freiburg, Germany) was used for band detection.