Early electrocortical changes consistent with ischemic preconditioning in rat.

Abstract Ischemic preconditioning (IPC) of the brain describes the neuroprotection induced by a short, conditioningischemic episode (CIE) to a subsequent severe (test) ischemic episode (TIE). Most of the supporting evidencefor IPC is based on histological assessment, several days after TIE. The aim of this study is to investigate ifchanges induced by IPC can be detected within 30 min of reperfusion following the ischemic episode. A ratmodel of "four-vessel occlusion" transient global cerebral ischemia and parametric analysis of electrocor-ticogram were used. A control group was subjected directly to a 10 min TIE, and in a preconditioned group TIEwas induced 48 h after a 3 min CIE. Quantitative histology was performed 48 h after TIE. Our key finding isthat, 30 min after reperfusion, there is a significant increase in the electrocortical slow activity in the controlgroup but not in the preconditioned group. Moreover the increase inversely correlates with the degree of elec-trocortical suppression during seconds 10 to 15 after the onset of the ischemic episode.