REGIONAL DIFFERENCES IN GLIAL-CELL MODULATION OF SYNAPTIC TRANSMISSION

Metabolic integrity of glial cells in field CA1 of the guinea pig hipp ocampus is critical to maintenance of synaptic transmission (Keyser an d Pellmar [1994] Glia 10:237-243). To determine if this tight glial-ne uronal coupling is equally important in other brain regions, we compar ed the effect of fluoroacetate (FAC), a glial specific metabolic block er, on synaptic transmission in field CA1 to synaptic transmission in area dentata (DG). FAC was significantly more effective in decreasing synaptic potentials in CA1 than in DC. A similar regional disparity in the FAC-induced decrease in ATP levels was evident. Isocitrate, a gli al specific metabolic substrate, prevented the FAC-induced synaptic de pression in both CA1 and DC. The results suggest that glia of CA1 and dentate respond differently to metabolic challenge. Modulation of this glial-neuronal coupling could provide a regionally specific mechanism for synaptic plasticity. Additionally, site-specific glial-neuronal i nteractions can impact on a variety of physiological and pathophysiolo gical conditions. (C) 1997 Wiley-Liss, Inc.