TEMPORAL CORRELATION BETWEEN ADENOSINE OUTFLOW AND SYNAPTIC POTENTIALINHIBITION IN RAT HIPPOCAMPAL SLICES DURING ISCHEMIA-LIKE CONDITIONS

The temporal correlation between adenosine outflow and changes in fiel d excitatory post synaptic potentials (fEPSP) occurring during ischemi a-like conditions was investigated in rat hippocampal slices. Five-min ute long ischemia-like conditions resulted in a 100% depression of fEP SP amplitude, followed by a complete recovery after 6-7 min of reperfu sion. By reducing the duration of the ischemic insult to 2 min, fEPSP was depressed by 50%. During both 5 and 2 min of ischemia-like conditi ons, a significant increase in adenosine outflow was detected. During reperfusion, when fEPSP amplitude recovered completely, the adenosine level in the extracellular fluid returned to basal values. The strict relationship between the increase in adenosine outflow and fEPSP inhib ition supports the hypothesis that adenosine is largely responsible fo r the synaptic transmission depression during cerebral ischemia. (C) 1 998 Elsevier Science B.V. All rights reserved.