L-glutamate decreases glucose utilization by rat cortical astrocytes.
Microenvironmental changes including elevated levels of L-glutamate, ionic homeostasis, acidification, and oxygen level are associated with brain insults. Their effects on energy metabolism were studied in cultured astrocytes. L-glutamate caused a decrease in lactate accumulation through the activation of transporter in astrocytes in a concentration- and time-dependent manner. Decreases in glucose uptake, lactate synthesis and accumulation as well as increases in mitochondrial activity indicated a switch of the astrocytic metabolism from glycolytic to oxidative. Environmental changes co-operated with L-glutamate to regulate the metabolic strategy, e.g. KCl and oxygen deprivation reversed but acidification exacerbated the L-glutamate-mediated decrease in lactate accumulation. Taken together, during chronic exposure, oxidation of non-glucose substrates such as L-glutamate fuels the active transport of L-glutamate into astrocytes.
Liao
Su-Lan
SL
Department of Education and Research, Taichung Veterans General Hospital, No. 160, Section 3, Taichung-Gang Road, Taichung 407, Taiwan.
Chen
Chun-Jung
CJ
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001930:Brain Injuries / Q000378:metabolism* / Q000503:physiopathology; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D027342:Excitatory Amino Acid Transporter 2 / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects / Q000502:physiology; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007477:Ions / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D027342:Excitatory Amino Acid Transporter 2; D007477:Ions; D019344:Lactic Acid; D018698:Glutamic Acid; D011189:Potassium Chloride; D005947:Glucose; D010100:Oxygen