Facilitatory effect of phorbol ester on 2-deoxyglucose uptake in rat hippocampal slices

It is well known that synaptic potentiation in the hippocampus can be produced by phorbol ester, a protein kinase C activator. The 2-deoxyglucose uptake is an index of regional glucose utilization which predominantly reflects activity in the axonal terminal of neuronal pathways. In the present experiment, therefore, we examined whether application of phorbol ester produces a facilitatory effect on 2-deoxyglucose uptake by the rat hippocampus in vitro. The application of phorbol-12,13-dibutyrate (PdBU) produced an elevation of 2-deoxyglucose uptake, while pretreatment with PdBU for 60 min eliminated the pdBU-induced elevation. Pretreatment with protein kinase C inhibitors, K252a (0.1 and 1 μM) or staurosporine (0.1 and 1 μM), was found to block significantly the PdBU-induced elevation of 2-deoxyglucose uptake. In addition, the facilitatory effect of glutamate, quisqualate and carbachol on 2-deoxyglucose uptake was reduced by pretreatment with PdBU. In the present experiment, we demonstrated that application of phorbol ester caused an elevation of 2-deoxyglucose uptake, which is linked in turn to neuronal activity, suggesting a positive relationship between protein kinase C activation and energy consumption.