Effects of glycolytic metabolites on preservation of high energy phosphate level and synaptic transmission in the granule cells of guinea pig hippocampal slices

Abstract

The present study was undertaken to investigate whether neural activity of hippocampal slices can be preserved after replacingd-glucose with glycolytic intermediate metabolites such as lactate, pyruvate and citrate or with other sugars such as fructose, mannose, maltose, glucosamine, sucrose and galactose. As an index of neural activity, population spikes (PS) were recorded in the granule cell layers after electrical stimulation to the perforant path of guinea pig hippocampal slices. In addition, we determined the levels of ATP and creatine phosphate (CrP) in each slice after the replacement ofd-glucose with these substrates, and correlated it with the neural activity. Substrates other thand-glucose could not maintain the PS for even 20 min although the slices perfused with medium containing lactate, pyruvate, galactose, fructose and maltose maintained similar levels of ATP and CrP as in slices incubated in thed-glucose-containing medium. These results indicate thatd-glucose is essential for the preservation of synaptic activity in addition to its main role as the substrate for energy production to maintain the levels of high energy phosphates.