Evidence for Specific Synaptosomal Localization of Exogenous Accumulated Taurine1

Equilibrium or incomplete equilibrium density gradient centrifugation was used to characterize the subcellular localization of exogenous [3 5S]taurine which was taken up by minces or homogenates of rat cerebral cortex. [3 5S]Taurine is accumulated in synaptosomes, which sediment more slowly than l‐[3H]norepinephrine‐accumulating particles. When [3 5S]taurine and [3H]GABA are accumulated by minces, a small difference in the sedimentation profile of taurine and GABA was observed, but no difference was found when taurine and intrasynaptosomal potassium were compared. However, potassium sedimented more slowly after incubation of homogenates than of minces. These data give evidence for the accumulation of [3 5S]taurine by a specific synaptosomal population.