Cytospectrometric studies on the lactate dehydrogenase isoenzymes in functionally different neuron-neuroglia units. II. Species and strain differences and effects of histotoxic hypoxia and audiogenic convulsions.

Cytospectrophotometric determination of H- and M-forms of LDH has shown that in white mice as compared with Wistar rats the activity ratio of H- to M-forms is lower in cerebral cortex neurons but higher in spinal cord motoneurons. No statistically significant species difference has been found in cerebellum PURKINJE cells as well as in the perineuronal glia of all the areas studied. Rats of KRUSHINSKY-MOLODKINA strain with hereditary high sensitivity to audiogenic convulsions differed from Wistar rats only with higher H- to M-form activity ratio in cerebellum PURKINJE cells and in their glial satellite cells. Histotoxic hypoxia in mice due to KCN injection gave rise in 15 min to activation of M-forms of LDH in spinal cord motoneurons and spinal ganglia neurons, of H-forms in cerebral and cerebellar cortex neurons and of both forms in the neuroglial cells adjacent to cerebellum PURKINJE neurons. Audiogenic convulsions in KRUSHINSKY-MOLODKINA rats induced an increase of H-form activity of LDH in the perineuronal glia of spinal cord anterior horns and of M-form activity in cerebellum PURKINJE cells while decrease of M-forms of cerebellum neuroglia. An importance of multiple forms of enzymes for the fine functional regulation of the cell biochemical pattern is discussed.