Summary
A method for the determination of GABA by derivatization with 2,4,6-trinitrobenzenesulphonic acid and subsequent separation and quantitation by HPLC with electrochemical detection was characterized with respect to specificity, reproducibility and sensitivity. No other amino acid occurring in significant amounts in the brain was found to interfere; however, adequate separation of the derivatives of GABA and tryptophan must be carefully checked in each experiment. The sensitivity of the method is essentially determined by baseline noise, which mainly depends on the quality of the HPLC pump; under our conditions, it was about 2 ng/ml analyte. The coefficients of variation determined at two different concentrations relevant for the subsequent experiments were well below 10%. The method proved useful for the assessment of endogenous release of GABA from superfused rat cortical slices by electrical stimulation, which, in contrast to the basal release, was found to be completely calcium-dependent at stimulation frequencies of 5 and 12 Hz, under our conditions. Both stimulated and basal release of GABA was enhanced 4–5-fold by the inhibitor of GABA uptake, SK&F 89976 (10 μM).
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References
Farnebo LO (1971) Release of monoamines evoked by field stimulation — studies on some ionic and metabolic requirements. Acta Physiol Scand (Suppl) 371:19–27
Fonnum F, Storm-Mathisen J (1978) Localization of GABAergic neurons in the CNS. In: Iversen LL, Iversen SD, Snyder SH (eds) Handbook of psychopharmacology. Plenum Press, New York, pp 357–401
Gardner CR, Richards MH (1981) Presence of radiolabelled metabolites in release studies using [3H]γ-aminobutyric acid. J Neurochem 36:1590–1593
Johnston GAR, Stephanson AL, Twitchin B (1976) Uptake and release of nipecotic acid by rat brain slices. J Neurochem 26:83–87
Katz RI, Chase TN, Kopin IJ (1969) Effects of ions on stimulus-induced release of amino acids from mammalian brain slices. J Neurochem 16:961–967
Limberger N, Spaeth L, Starke K (1986) Release of previously incorporated γ-[3H]aminobutyric acid in rabbit caudate nucleus slices. J Neurochem 46:1102–1108
Meldrum B (1978) Neurotransmitters and epilepsy. In: Legg NJ (ed) Neurotransmitter systems and their clinical disorders. Academic Press, New York, pp 167–181
Orrego F, Miranda R (1976) Electrically induced release of [3H]GABA from neocortical thin slices. Effects of stimulus waveform and of amino-oxyacetic acid. J Neurochem 26: 1033–1038
Potashner SJ (1979) Baclofen: Effects on amino acid release and metabolism in slices of the pig cerebral cortex. J Neurochem 32:103–109
Srinivasan V, Neal MJ, Mitchell JF (1969) The effect of electrical stimulation and high potassium concentration on the efflux of [3H]γ-aminobutyric acid from brain slices. J Neurochem 16:1235–1244
Szerb JC (1979) Relationship between Ca 2+-dependent and independent release of [3H]GABA evoked by high K+, veratridine or electrical stimulation from rat cortical slices. J Neurochem 32:1565–1573
Szerb JC, Ross ET, Gurevich L (1981) Compartments of labelled and endogenous γ-aminobutyric acid giving rise to release evoked by potassium and veratridine in rat cortical slices. J Neurochem 37:1186–1192
Szerb JC (1983) The release of [3H]GABA formed from [3H]glutamate in rat hippocampal slices: comparison with endogenous and exogenous labelled GABA. Neurochem Res 8:341–351
Waldmeier PC, Wicki P, Feldtrauer JJ, Baumann P (1988) Potential involvement of a baclofen-sensitive autoreceptor in the modulation of the release of endogenous GABA from rat brain slices in vitro. Naunyn-Schmiedeberg's Arch Pharmacol 337:289–295
Yamamoto T, Nanjoh C, Kuruma I (1985) Determination of endogenous GABA released from the cerebral cortex slices of the rat by high-performance liquid chromatography with a series-dual electrochemical detector. Neurochem Int 7:77–82
Yunger LM, Fowler PJ, Zarevics P, Setler PE (1984) Novel inhibitors of γ-aminobutyric acid (GABA) uptake: anticonvulsant actions in rats and mice. J Pharmacol Exp Ther 228:109–115
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Waldmeier, P.C., Wicki, P., Feldtrauer, J.J. et al. The measurement of the release of endogenous GABA from rat brain slices by liquid chromatography with electrochemical detection. Naunyn-Schmiedeberg's Arch Pharmacol 337, 284–288 (1988). https://doi.org/10.1007/BF00168840
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DOI: https://doi.org/10.1007/BF00168840