title: Pentylenetetrazole affects metabolism of astrocytes in culture.
abstract: Cortical and cerebellar astrocytes were cultured in medium containing pentylenetetrazole (PTZ), a gamma-aminobutyric acid (GABA)(A) receptor antagonist, for 3 weeks (up to 6 mM) or 2 hr (10 mM). Cells were incubated in medium containing [U-(13)C]glutamate (0.5 mM) and unlabeled glucose (3 mM) for 2 hr and cell extracts and media were analyzed by (13)C magnetic resonance (MR) spectroscopy and high-performance liquid chromatography (HPLC). When cerebellar astrocytes were incubated with PTZ for 2 hr, the amount of glucose removed from the medium and glucose and [U-(13)C]glutamate oxidation were decreased. Metabolism in cortical astrocytes was affected only slightly; amounts of glutathione and aspartate were decreased. When cerebellar and cortical cells were cultured in the presence of PTZ for 3 weeks, the amount of glucose removed from the medium and lactate formed were increased, indicating increased glycolytic activity. Despite the increased intracellular [U-(13)C]glutamate concentration in both types of astrocytes cultured with PTZ, labeled glutamine and glutathione were unchanged, indicating intracellular compartmentation. The amount of cellular protein was decreased at 6 mM PTZ for cerebellar astrocytes and 1 mM for cortical astrocytes, indicating a differential sensitivity to the effects of PTZ. In conclusion, mitochondrial metabolism and glycolysis were decreased by short-term incubation with PTZ in cerebellar astrocytes, whereas long-term incubation affected both types of astrocytes, leading to increased glycolysis.
authors.affiliation: Department of Neuroscience, Norwegian University of Science and Technology, Olav Kyrresgatan 3, N-7489 Trondheim, Norway.
authors.forename: Hong
authors.initials: H
authors.lastname: Qu
authors.forename: Haytham
authors.initials: H
authors.lastname: Eloqayli
authors.forename: Ursula
authors.initials: U
authors.lastname: Sonnewald
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D001921:Brain / Q000166:cytology*; D002247:Carbon Isotopes / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004305:Dose-Response Relationship, Drug; D018756:GABA Antagonists / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D051379:Mice; D010433:Pentylenetetrazole / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism; D013997:Time Factors
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D018756:GABA Antagonists; D011506:Proteins; D018698:Glutamic Acid; D007770:L-Lactate Dehydrogenase; D005947:Glucose; D010433:Pentylenetetrazole