The effect of the convulsant agent, catechol, on neurotransmitter uptake and release in rat brain slices

1 The effect of catechol on uptake and K+-stimulated release of gamma-aminobutyric acid (GABA), D-aspartate, noradrenaline and acetylcholine has been studied in slices of cerebral cortex and thalamus. 2 Low concentrations of catechol did not influence the uptake of any of the neurotransmitters in either brain area. 3 Noradrenaline release was unaffected by catechol. 4 Acetylcholine release from both cortical and thalamic slices was inhibited by high concentrations of catechol. This phenomenon is unlikely to be related to catechol-induced convulsions. 5 Catechol (100 microM) inhibited GABA release from cortical slices by 28%. However, at a concentration of 10 microM catechol enhanced the release of D-aspartate from thalamic slices by over 100%. 6 Potentiated release of excitatory amino acid transmitters may contribute to the enhanced excitability of thalamic cells which occurs during sensory myoclonus induced by low doses of catechol.