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Neurochemical Research

, Volume 7, Issue 2, pp 191–204 | Cite as

Turnover and release of GABA in rat cortical slices: Effect of a GABA-T inhibitor, gabaculine

  • John C. Szerb
Original Articles

Abstract

The turnover and release of endogenous and labeled GABA were followed in rat cortical slices after incubation with [3H]GABA. High performance liquid chromatography was used to measure endogenous GABA and to separate [3H]GABA from its metabolites. During superfusion with 3 mM K+ the slices rapidly lost their [3H]GABA content while maintaining constant GABA levels. Exposure to 50 mM K+ for 25 min caused an initial rapid rise in the release of both endogenous and [3H]GABA followed by a more rapid decline in the release of the latter. The specific activity of released GABA was two to four times higher than that in the slices. Depolarization lead to a net synthesis of GABA. The GABA-T inhibitor, gabaculine, (5 μM) in vitro arrested the metabolism of [3H]GABA and rapidly doubled the GABA content but did not significantly increase the high K+ evoked release of endogenous GABA. In vivo pretreatment with 0.5 mM/kg gabaculine quadrupled GABA content and increased both the spontaneous and evoked release of endogenous GABA but while its Ca2+-dependent release increased by 50%, the Ca2+-independent release was enhanced sevenfold. This large Ca2+-independent release of GABA is likely to have different functional significance from the normal Ca2+-dependent release.

Keywords

Liquid Chromatography High Performance Liquid Chromatography Functional Significance Rapid Decline Rapid Rise 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Publishing Corporation 1982

Authors and Affiliations

  • John C. Szerb
    • 1
  1. 1.Department of Physiology and BiophysicsDalhousie UniversityHalifaxCanada

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