Lactate, not pyruvate, is neuronal aerobic glycolysis end product: an in vitro electrophysiological study.
For over 60 years, a distinction has been made between aerobic and anaerobic glycolysis based on their respective end products: pyruvate of the former, lactate of the latter. Recently we hypothesized that, in the brain, both aerobic and anaerobic glycolysis terminate with the formation of lactate from pyruvate by the enzyme lactate dehydrogenase (LDH). If this hypothesis is correct, lactate must be the mitochondrial substrate for oxidative energy metabolism via its oxidation to pyruvate, plausibly by a mitochondrial LDH. Here we employed electrophysiology of the rat hippocampal slice preparation to test and monitor the effects of malonate and oxamate, two different LDH inhibitors, and glutamate, a neuronal activator, in experiments, the results of which support the hypothesis that lactate, at least in this in vitro setting, is indeed the principal end product of neuronal aerobic glycolysis.
Schurr
A
A
Department of Anesthesiology and Perioperative Medicine, University of Louisville, School of Medicine, Louisville, KY 40202, USA. a0schu01@louisville.edu
Payne
R S
RS
D000200:Action Potentials / Q000187:drug effects; D000332:Aerobiosis / Q000502:physiology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology / Q000379:methods*; D005947:Glucose / Q000494:pharmacology; D006019:Glycolysis / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008314:Malonates / Q000494:pharmacology; D008954:Models, Biological; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009930:Organic Chemicals / Q000494:pharmacology; D019289:Pyruvic Acid / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D008314:Malonates; D009930:Organic Chemicals; D019344:Lactic Acid; C048603:oxamate (repellent); D019289:Pyruvic Acid; C030290:malonic acid; D007770:L-Lactate Dehydrogenase; D005947:Glucose