Stimulation of energy metabolism by alpha-adrenergic agonists in primary cultures of astrocytes.
Noradrenaline effects on glucose oxidation were studied in primary cultures of astrocytes. CO2 formation from labeled glucose was enhanced in the presence of noradrenaline. The stimulatory effect by noradrenaline was exerted both on lactate formation (approximately 20%) and on tricarboxylic acid activity (CO2 production from glutamate) (approximately 40%). The effect was, at least partly, exerted on the alpha-ketoglutarate dehydrogenase step. The EC50 value for noradrenaline on lactate formation was significantly lower (60 nM) than that on oxidative metabolism (1,900 nM). Studies with specific adrenergic agonists and antagonists showed that various receptor subtypes are involved. Thus, the effect on lactate formation was mediated exclusively by stimulation of an alpha 1 receptor whereas oxidative metabolism was enhanced by both alpha 1 and alpha 2 receptor stimulation. No effects were exerted by beta receptor agonists or antagonists.
Department of Pharmacology, University of Saskatchewan, Saskatoon, Canada.
K V
KV
Subbarao
L
L
Hertz
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D002952:Citric Acid Cycle / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D007773:Lactates / Q000096:biosynthesis; D019344:Lactic Acid; D051379:Mice; D009638:Norepinephrine / Q000502:physiology*; D010085:Oxidative Phosphorylation / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000145:classification / Q000187:drug effects / Q000502:physiology
D000316:Adrenergic alpha-Agonists; D007773:Lactates; D011942:Receptors, Adrenergic, alpha; D019344:Lactic Acid; D005947:Glucose; D009638:Norepinephrine