Brain levels of NADH and NAD+ under hypoxic and hypoglycaemic conditions in vitro

• Published in: Journal of neurochemistry Vol. 51; no. 1; p. 172
• Main Authors: Garofalo, O, Cox, D W, Bachelard, H S
• Format: Journal Article
• Language: English
• Published: England 01.07.1988
• Subjects: Adenosine Triphosphate - metabolism; Animals; Brain - metabolism; Female; Glucose - administration & dosage; Glucose - metabolism; Guinea Pigs; Hypoglycemia - metabolism; Hypoxia, Brain - metabolism; In Vitro Techniques; Lactates - metabolism; Lactic Acid; NAD - metabolism; Oxidation-Reduction; Oxygen - administration & dosage; Phosphocreatine - metabolism; Pyruvates - metabolism; Pyruvic Acid
• ISSN: 0022-3042
• DOI: 10.1111/j.1471-4159.1988.tb04851.x

The effects of hypoxia and hypoglycaemia on the redox state in vitro have been studied. NADH and NAD+ were extracted simultaneously from superfused cerebral cortex slices and assayed by bioluminescence. The results show a nonsignificant increase in NADH and the redox ratio in "mild hypoxia," whereas "severe hypoxia" produced an increase of over 200% in NADH and in the NADH/NAD+ ratio. When the glucose in the incubation medium was reduced from its control value of 10 mM to 0.5 mM, significant decreases in NADH and the redox ratio to 60% of control value were observed. Further decreasing the glucose to 0.2 mM gave lower levels of NADH and the redox ratio (40% of control). The effects on the redox state of alternative substrates to glucose were also tested. Replacement of glucose by 10 mM pyruvate decreased the NADH by 77% and the NADH/NAD+ ratio by 79%. Replacement of glucose with 10 mM lactate gave decreases of 70% and 71%, respectively, whereas in the presence of 15 mM 2-deoxyglucose and 5 mM glucose, the NADH was decreased by 56% and the ratio by 50%. The results are discussed in relation to levels of creatine phosphate and ATP, as well as evoked action potentials, observed from parallel studies.