Excitatory amino acids evoke taurine release from cerebral cortex slices from adult and developing mice

Glutamate, aspartate and the agonists of the excitatory amino acid receptors, N-methyl-D-aspartate, kainate and quisqualate, evoked more release of both endogenous and preloaded exogenous taurine from cerebral cortical slices from three-day-old than from specimens from adult mice. The N-methyl-D-aspartate- and quisqualate-evoked release was blocked by D-2-amino-5-phosphonovalerate and glutamatediethylester, respectively, in three-day-old mice but not in the adults. The kainate-evoked release was not affected by gamma-D-glutamyltaurine and gamma-D-glutamylglycine in either age group. Exposure of the slices to excitatory amino acids and their agonists caused intracellular swelling of the slices, which was directly proportional to the increase in taurine release in adult mice. In three-day-old mice the correlation between the swelling and taurine release was less pronounced. The excitatory amino acid receptors seem to modify more effectively the release of taurine in the developing than the adult brain. In the adults the evoked release of taurine may be related to cell volume regulation in the context of the excitation-coupled ionic and water movements across plasma membranes.