Activities of Lactate, Glutamate, and Malate Dehydrogenases in Dorsal Root Ganglion Neurons and Schwann Cells

In the central nervous system there are distinct differences in metabolism between neurons and glial cells. By contrast, the metabolism of dorsal root ganglion (DRG) neurons and Schwann cells in the peripheral nervous system (PNS) have not been similarly characterized. Three energy- metabolizing enzymes, lactate, glutamate, and malate dehydrogenases (LDH, GDH, and MDH, respectively) were chosen to investigate our hypothesis that there are metabolic differences between DRG neurons and Schwann cells. Activities of these enzymes were therefore studied employing the Clark and Lai assays. Consistent with our hypothesis, the activities of these enzymes differed between the two neural cell types. GDH and LDH activities were much higher in Schwann cells than in DRG neurons while MDH activity was slightly higher in DRG neurons than in Schwann cells. Because our findings may have physiological/pathophysiological implications in normal and disease conditions in the PNS, further characterization of the metabolic properties the two cell types is warranted