Oxidation of 14C-labeled compounds perfused by microdialysis in the brains of free-moving rats

✍ Scribed by H. Ronald Zielke; Carol L. Zielke; Peter J. Baab

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 154 KB
• Volume: 85
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.21424

✦ Synopsis

Abstract

The oxidative capacity of the brain for alternate substrates, glucose, lactate, pyruvate, acetate, glutamate, and glutamine was determined by using microdialysis to infuse ^14^C‐labeled compounds into the interstitial fluid of adult rat brain and by collecting the brain‐generated ^14^CO~2~ from the dialysis eluate. All compounds were readily oxidized. The recovery of ^14^CO~2~ was enhanced for those compounds metabolically close to entry into the TCA cycle or known to have a low interstitial concentration. Two compounds, pyruvate and lactate, demonstrated reciprocal competition when added as nonradioactive competitors. Oxidation of two amino acids, ^14^C‐glutamate and ^14^C‐glutamine, was stimulated by the addition of nonradioactive acetate and pyruvate. α‐Cyano‐4‐hydroxycinnamate decreased ^14^C‐lactate and ^14^C‐pyruvate oxidation, consistent with the transport of both compounds via a monocarboxylate transporter. The results of this in vivo study support the results of previous in vitro studies that showed that a wide range of compounds formed from glucose in the brain are also oxidized in the brain for energy production. © 2007 Wiley‐Liss, Inc.