Cysteine sulfinic acid uptake in cultured neuronal and glial cells.

The presence of an efficient high affinity uptake system for L-CSA has been demonstrated in cultured neuronal and glial cells of various types. In neurons and most glial cells L-CSA uptake is inhibited by acidic amino acids, L-glutamate and L-aspartate and requires sodium ions; however the sodium dependence varies from one cell type to the other. The characteristics of the uptake system change during cell maturation, especially in astroblasts. The predominance of CSA uptake in glial cells as compared to neurons, the similarity of the kinetic parameters and of the structural specificity of L-glutamate uptake suggest that both excitatory amino acids are transported by a common system. In view of accumulating evidence, the present results are in agreement with a role of CSA as a neurotransmitter and as a precursor for taurine biosynthesis in the central nervous system.