| Autor: |
Zielke HR; Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21010, USA. rzielke@umaryland.edu, Zielke CL, Baab PJ, Tildon JT |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of neurochemistry [J Neurochem] 2007 Apr; Vol. 101 (1), pp. 9-16. Date of Electronic Publication: 2007 Jan 04. |
| DOI: |
10.1111/j.1471-4159.2006.04335.x |
| Abstrakt: |
Glucose is the primary carbon source to enter the adult brain for catabolic and anabolic reactions. Some studies suggest that astrocytes may metabolize glucose to lactate; the latter serving as a preferential substrate for neurons, especially during neuronal activation. The current study utilizes the aconitase inhibitor fluorocitrate to differentially inhibit oxidative metabolism in glial cells in vivo. Oxidative metabolism of 14C-lactate and 14C-glucose was monitored in vivo using microdialysis and quantitating 14CO2 in the microdialysis eluate following pulse labeling of the interstitial glucose or lactate pool. After establishing a baseline oxidation rate, fluorocitrate was added to the perfusate. Neither lactate nor glucose oxidation was affected by 5 micromol/L fluorocitrate. However, 20 and 100 micromol/L fluorocitrate reduced lactate oxidation by 55 +/- 20% and 68 +/- 12%, respectively (p < 0.05 for both). Twenty and 100 micromol/L fluorocitrate reduced 14C-glucose oxidation by 50 +/- 14% (p < 0.05) and 24 +/- 19% (ns), respectively. Addition of non-radioactive lactate to (14)C-glucose plus fluorocitrate decreased 14C-glucose oxidation by an additional 29% and 38%, respectively. These results indicate that astrocytes oxidize about 50% of the interstitial lactate and about 35% of the glucose. By subtraction, neurons metabolize a maximum of 50% of the interstitial lactate and 65% of the interstitial glucose. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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