PROTEIN-SYNTHESIS AND ENERGY-METABOLISM IN HIPPOCAMPAL SLICES DURING EXTENDED (24 HOURS) RECOVERY FOLLOWING DIFFERENT PERIODS OF ISCHEMIA

Hippocampal slices were successfully maintained for 24 hours in vitro in a flow-through chamber by using a modified artificial CSF (amino ac ids included). Measurement of energy metabolism parameters (adenine nu cleotides) and the slice response to KCl-induced depolarization (relea se of GABA and aspartate) indicated that hippocampal slices were metab olically stable for at least 24 hours. The preparation was used to stu dy recovery of protein synthesis after different periods of in vitro i schemia (5, 10, or 15 min). Protein synthesis inhibition was only part ly reversed after 15 min of ischemia, but fully reversible after 5- or 10-min ischemia at 24 hours of recovery. Furthermore, the model was u sed to study a possible role of glutamate in postischemic inhibition o f protein synthesis. Glutamate receptor agonists (glutamate or quinoli nic acid) or antagonist (kynurenic acid) were applied during ischemia. Neither treatment affected the late (24 hours) outcome of ischemia, a rguing against the critical role of glutamate in ischemic cell damage. The present approach allows use of the hippocampal slice preparation in the study of delayed effects of ischemia of different duration.