MONOCARBOXYLATES (PYRUVATE AND LACTATE) AS ALTERNATIVE ENERGY SUBSTRATES FOR THE INDUCTION OF LONG-TERM POTENTIATION IN RAT HIPPOCAMPAL SLICES

We previously reported that mild hypoglycemic conditions hamper the in duction of long-term potentiation (LTP) in the CAI region of rat hippo campal slices. In the present study, we examined whether monocarboxyla tes (pyruvate and lactate) permit LTP induction when glucose is unavai lable. During glucose deprivation, pyruvate and lactate not only maint ained basal synaptic transmission but also allowed LTP induction, with pyruvate being more effective than lactate. Additionally, LTP inhibit ion by 5 mu M iodoacetate, a glycolytic inhibitor, was prevented by ad dition of pyruvate but not lactate. These results suggest that monocar boxylates can be effective alternative energy substrates for LTP induc tion when glucose is not available, However, lactate and pyruvate are not identical as energy sources for LTP induction. (C) 1997 Elsevier S cience Ireland Ltd.