Immunofluorescence and Histochemical Methods for Neural M₁ Pyruvate Kinase Localization

Abstract

The distribution of pyruvate kinase (ATP pyruvate phosphotransferase, EC 2.7.1.40) in the nervous system has been studied by both immunofluorescence and a histochemical procedure using nitro blue tetrazolium. The localization in various parts of rat central nervous system in situ, cerebellar and cerebral cortex, was compared to that found in vitro in cultures of cerebellum, spinal ganglia, cerebral astrocytes, and skin fibroblasts. (1) Pyruvate kinase was found predominantly in the cytoplasm of neuronal cell bodies. (2) Large neurons were better visualized than small ones. (3) No glial localization was clearly demonstrated in situ, although this does not rule out the presence of some M1 pyruvate kinase. (4) Regions expected to be rich in nerve terminals, such as the cerebellar glomeruli or the cerebellar molecular layer, showed intense staining even when the cell bodies themselves were negative. This was expected, owing to the previous demonstration of the presence of M1 pyruvate kinase in nerve ending by subcellular fractionation methods. (5) The localization was similar in situ and in tissue culture, except that nerve processes were better seen in the latter and astrocytes were sometimes stained in vitro. (6) Variation in intensity of staining was observed in similar cell types in the same section or in the same culture. This could represent different metabolic or functional or maturational states.

A metabolic switch in brain: glucose and lactate metabolism modulation by ascorbic acid

“…Although it has been demonstrated that the expression of transporters and enzymes involved in the hypothesis of this review are similar to that observed in situ (Castro et al. 2007, 2008; Gali et al. 1981; Loaiza et al.…”

“…These differences might be of importance for regulation of brain glycolysis in the different cellular compartments of the brain. PK is expressed in neurons and astrocytes (Gali et al. 1981).…”

Is Melanoma a stem cell tumor? Identification of neurogenic proteins in trans-differentiated cells

“…The pyruvate kinase isoenzyme M1 (KPYM) was downregulated in trans-differentiated cells but its presence is considered important for nerve endings [30]. Likewise the down regulation of neurotrophic factor-3 (NT-3) in neuronal cells is noteworthy since this factor is necessary for the development of mature neurons and enteric nervous system but it is not essential for the generation of newly differentiated neural cells [31].…”