Stimulus-induced release of endogenous amino acids from skins containing the lateral-line organ in Xenopus laevis.

The release of endogenous amino acids from skins of Xenopus laevis was studied by comparing the effects of pulsatile water motion on the efflux of glutamate and aspartate from isolated skins with and without lateral-line stitches. The stimulated efflux of glutamate from stitch skins was significantly greater than its stimulated efflux from non-stitch skins (p < 0.01). The results for aspartate were less clear cut. Although the source and mechanisms underlying the greater stimulated efflux from stitch skins remain to be determined, the results demonstrate that differences can be detected between stitch and non-stitch skins under stimulus conditions which should induce release of the afferent transmitter substance(s).