[Effect of GABA on the synthesis, uptake and release of noradrenaline-H3 from brain slices]

The data obtained showed that GABA exerted no effect on the synthesis and putake of H3-NE while increasing its loss from slices preincubated for 5 min before incubation for 30 min with H3-NE for uptake. When slices were preincubated for 30 before the addition of H3-NE the effect of GABA on NE content in the slices was reversed. A similar reversal of the GABA effect occurred when varying the preincubation period of slices subjected to prolonged electrical stimulation. The uptake and release of H3-NE were not affected by the duration of the preincubation period. The reversal of the GABA effect on H3-NE did not correlate with the depletion of endogenous stores of NE and may be due to the changes in the ionic composition of slices in the course of the prolonged incubation.