Neurochemical Research

, Volume 30, Issue 2, pp 225–235

Krebs Cycle Intermediates Modulate Thiobarbituric Acid Reactive Species (TBARS) Production in Rat Brain In Vitro

Authors

  • Robson L. Puntel
    • Departamento de Química, Centro de Ciências Naturais e ExatasUniversidade Federal de Santa Maria
  • Cristina W. Nogueira
    • Departamento de Química, Centro de Ciências Naturais e ExatasUniversidade Federal de Santa Maria
    • Departamento de Química, Centro de Ciências Naturais e ExatasUniversidade Federal de Santa Maria
    • Departamento de Química, CCNEUniversidade Federal de Santa Maria
Article

DOI: 10.1007/s11064-004-2445-7

Cite this article as:
Puntel, R.L., Nogueira, C.W. & Rocha, J.B.T. Neurochem Res (2005) 30: 225. doi:10.1007/s11064-004-2445-7

Abstract

The aim of this study was to investigate the effect of Krebs cycle intermediates on basal and quinolinic acid (QA)- or iron-induced TBARS production in brain membranes. Oxaloacetate, citrate, succinate and malate reduced significantly the basal and QA-induced TBARS production. The potency for basal TBARS inhibition was in the order (IC50 is given in parenthesis as mM) citrate (0.37) > oxaloacetate (1.33) = succinate (1.91) >> malate (12.74). α-Ketoglutarate caused an increase in TBARS production without modifying the QA-induced TBARS production. Cyanide (CN) did not modify the basal or QA-induced TBARS production; however, CN abolished the antioxidant effects of succinate. QA-induced TBARS production was enhanced by iron ions, and abolished by desferrioxamine (DFO). The intermediates used in this study, except for α-ketoglutarate, prevented iron-induced TBARS production. Oxaloacetate, citrate, α-ketoglutarate and malate, but no succinate and QA, exhibited significantly iron-chelating properties. Only α-ketoglutarate and oxaloacetate protected against hydrogen peroxide-induced deoxyribose degradation, while succinate and malate showed a modest effect against Fe2+/H2O2-induced deoxyribose degradation. Using heat-treated preparations citrate, malate and oxaloacetate protected against basal or QA-induced TBARS production, whereas α-ketoglutarate induced TBARS production. Succinate did not offer protection against basal or QA-induced TBARS production. These results suggest that oxaloacetate, malate, succinate, and citrate are effective antioxidants against basal and iron or QA-induced TBARS production, while α-ketoglutarate stimulates TBARS production. The mechanism through which Krebs cycle intermediates offer protection against TBARS production is distinct depending on the intermediate used. Thus, under pathological conditions such as ischemia, where citrate concentrations vary it can assume an important role as a modulator of oxidative stress associated with such situations.

Keywords

Krebs cycle intermediateslipid peroxidationquinolinic acidironantioxidant

Copyright information

© Springer Science+Business Media, Inc. 2005