Role of sodium and potassium ions in regulation of glucose metabolism in cultured astroglia
Autor: | Bernard F. Driscoll, Shinichi Takahashi, Mona J. Law, Louis Sokoloff |
---|---|
Rok vydání: | 1995 |
Předmět: |
medicine.medical_specialty
Time Factors Bicarbonate Sodium Glutamic Acid chemistry.chemical_element Gestational Age Tetrodotoxin Deoxyglucose Ouabain Rats Sprague-Dawley chemistry.chemical_compound Fetus Pregnancy Internal medicine medicine Extracellular Animals Carbon Radioisotopes Monensin Phosphorylation Na+/K+-ATPase Cells Cultured 6-Cyano-7-nitroquinoxaline-2 3-dione Neurons Veratridine Multidisciplinary Chemistry Metabolism Molecular biology Corpus Striatum Rats Kinetics Glucose Endocrinology 2-Amino-5-phosphonovalerate Bucladesine Astrocytes Potassium Female Research Article medicine.drug |
Zdroj: | Proceedings of the National Academy of Sciences. 92:4616-4620 |
ISSN: | 1091-6490 0027-8424 |
Popis: | Effects of increasing extracellular K+ or intracellular Na+ concentrations on glucose metabolism in cultures of rat astroglia and neurons were examined. Cells were incubated in bicarbonate buffer, pH 7.2, containing 2 mM glucose, tracer amounts of [14C]deoxyglucose ([14C]dGlc), and 5.4, 28, or 56 mM KCl for 10, 15, or 30 min, and then for 5 min in [14C]dGlc-free buffer to allow efflux of unmetabolized [14C]dGlc. Cells were then digested and assayed for labeled products, which were shown to consist of 96-98% [14C]deoxyglucose 6-phosphate. Increased K+ concentrations significantly raised [14C]deoxyglucose 6-phosphate accumulation in both neuronal and mixed neuronal-astroglial cultures at 15 and 30 min but did not raise it in astroglial cultures. Veratridine (75 microM), which opens voltage-dependent Na+ channels, significantly raised rates of [14C]dGlc phosphorylation in astroglial cultures (+20%), and these elevations were blocked by either 1 mM ouabain, a specific inhibitor of Na+,K(+)-ATPase (EC 3.6.1.37), or 10 microM tetrodotoxin, which blocks Na+ channels. The carboxylic sodium ionophore, monensin (10 microM), more than doubled [14C]dGlc phosphorylation; this effect was only partially blocked by ouabain and unaffected by tetrodotoxin. L-Glutamate (500 microM) also stimulated [14C]dGlc phosphorylation in astroglia--not through N-methyl-D-aspartate or non-N-methyl-D-aspartate receptor mechanisms but via a Na(+)-dependent glutamate-uptake system. These results indicate that increased uptake of Na+ can stimulate energy metabolism in astroglial cells. |
Databáze: | OpenAIRE |
Externí odkaz: |