Immunohistochemistry to determine the expression of GK in the CA1 region of the (A–D) ischemia and (E–H) IPC + ischemia groups 1, 2 and 5 days following ischemia-reperfusion. GK immunoreactivity was readily detected in the SP in the sham group. GK immunoreactivity in the SP was decreased from 2 days post-ischemia, and GK immunoreactivity was markedly decreased (*) 5 days post-ischemia. However, in the IPC-operated sham- and IPC + ischemia-operated groups, GK immunoreactivity was markedly increased in the SP of CA1, and was maintained until 5 days post-ischemia. Scale bar=50 µm. GK, glucokinase; SP, stratum pyramidale; SO; stratum oriens, SR; stratum radiatum; IPC, ischemic preconditioning.