Localization of glyoxylate dehydrogenase and glyoxylate-complex molecules in the rat prefrontal cortex: Enzyme histochemical and immunocytochemical study

Glyoxylic acid is synthesized and catabolized in cells of vertebrates; seve ral pathways have been described. In previous papers, we have demonstrated the localization in some areas of the rat cerebral cortex both of beta-NAD- dependent glyoxylate dehydrogenase (glyoDH), using an enzymohistochemical m ethod, and of glyoxylate-complex molecules, using immunocytochemical proced ures, In this study we have applied these two techniques in various areas o f the prefrontal cortex with different histological cytoarchitecture. GlyoD H has been located in most neurons, in some glial cells, and in capillary w all structures in all cortical layers of all areas of the rat prefrontal co rtex. Antibodies against glyoxylate-complex molecules showed positive immun oreactivity in scattered neurons, mostly of multipolar or stellate appearan ce, from layers III, IV, and V in the medial precentral area, but not in co rtical areas 24, 25, or 32 of the prefrontal cortex. Immunoreaction was fou nd in the periphery of neuronal perikarya and in some of their processes. T hese results demonstrate the existence of a particular area-dependent neuro nal cortical system, of specific but uncertain function, related to glyoxyl ic acid and/or glyoxylate compounds. At the electron microscope level, posi tive reaction was associated with synaptic sites, axonal filaments, glial c ells, and several components of the blood-brain barrier, These localization s suggest the involvement of glyoxylate derivatives in synaptic functioning and also in glial cell functions. (C) 2000 Wiley-Liss, Inc.