Journal of Neural Transmission

, Volume 116, Issue 3, pp 291–300

Elevated endogenous GABA concentration attenuates glutamate–glutamine cycling between neurons and astroglia

Basic Neurosciences, Genetics and Immunology - Original Article

DOI: 10.1007/s00702-009-0186-0

Cite this article as:
Yang, J. & Shen, J. J Neural Transm (2009) 116: 291. doi:10.1007/s00702-009-0186-0

Abstract

In this study, the relationship between endogenous brain GABA concentration and glutamate–glutamine cycling flux (Vcyc) was investigated using in vivo 1H and 1H{13C} magnetic resonance spectroscopy techniques. Graded elevations of brain GABA levels were induced in rat brain after administration of the highly specific GABA-transaminase inhibitor vigabatrin (γ-vinyl-GABA). The glial-specific substrate [2-13C]acetate and 1H{13C} magnetic resonance spectroscopy were used to measure Vcyc at different GABA levels. Significantly reduced Vcyc was found in rats pretreated with vigabatrin. The reduction in group mean Vcyc over the range of GABA concentrations investigated in this study (1.0 ± 0.3–5.1 ± 0.5 μmol/g) was found to be nonlinear: ΔVcyc/Vcyc = [GABA (μmol/g)]−0.35 − 1.0 (r2 = 0.98). The results demonstrate that Vcyc is modulated by endogenous GABA levels, and that glutamatergic and GABAergic interactions can be studied in vivo using noninvasive magnetic resonance spectroscopy techniques.

Keywords

GABAVigabatrinGlutamateMagnetic resonance spectroscopy

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Molecular Imaging Branch National Institute of Mental Health Intramural Research Program, National Institutes of HealthBethesdaUSA
  2. 2.Samsung Biomedical Research InstituteSeoulKorea