Elevated endogenous GABA concentration attenuates glutamate–glutamine cycling between neurons and astroglia
2009; Springer Science+Business Media; Volume: 116; Issue: 3 Linguagem: Inglês
10.1007/s00702-009-0186-0
ISSN1435-1463
Autores Tópico(s)Ion channel regulation and function
ResumoIn this study, the relationship between endogenous brain GABA concentration and glutamate–glutamine cycling flux (V cyc) 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 V cyc at different GABA levels. Significantly reduced V cyc was found in rats pretreated with vigabatrin. The reduction in group mean V cyc 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: ΔV cyc/V cyc = [GABA (μmol/g)]−0.35 − 1.0 (r 2 = 0.98). The results demonstrate that V cyc is modulated by endogenous GABA levels, and that glutamatergic and GABAergic interactions can be studied in vivo using noninvasive magnetic resonance spectroscopy techniques.
Referência(s)