The environmental enrichment effect upon cortical growth is neutralized by concomitant pharmacological suppression of active sleep in female rats

D-alpha-Aminoadipate (D-AA) and L-alpha-aminoadipate (L-AA) were found to significantly reduce spontaneous efflux of 14C]L-aspartate from preloaded rat brain slices. Only D-AA significantly reduced spontaneous efflux of 14C]L-glutamate and 3H]gamma-aminobutyric acid (GABA); L-AA reduced but not significantly the efflux of these 2 labeled amino acids. D-AA reduced K+-stimulated release of 14C]L-aspartate and 14C]L-glutamate significantly, and L-AA that of 3H]GABA significantly. Since both D-AA and L-AA inhibit the uptake of L-aspartate, L-glutamate and GABA, their effects on the efflux of these amino acids are more specific. These results also suggest that it is unlikely that the depressant effect of D-AA, and the excitant effect of L-AA on neurons when applied locally by iontophoresis are secondary to the accelerated or decelerated release of more specific transmitter amino acids from neighboring cells.