Effect of taurine on passive ion transport in rat brain synaptosomes

Taurine, in concentrations greater than 10 mM, was found to have an inhibitory effect on passive calcium uptake and release in rat brain synaptosomal preparations. Amino acids similar to that of taurine in chemical structure, β-alanine, hypotaurine, homotaurine and γ-amino-butyric acid were also shown to inhibit calcium uptake in this preparation. Taurine, though, did not alter the permeability of these preparations to sodium or potassium. It thus appears that taurine and chemically related amino acids can alter calcium movements in these preparations. It is postulated that this effect is due to binding to specific taurine sites in the synaptosomal membranes.