Author(s): Nusetti S, Urbina M, Lima L
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Abstract BACKGROUND: Taurine and zinc exert neurotrophic effects in the central nervous system. Current studies demonstrate that Na+/Cl- dependent neurotransmitter transporters, similar to that of taurine, are modulated by micromolar concentrations of zinc. This study examined the effect of zinc sulfate ex vivo on [3H]taurine transport in goldfish retina. METHODS: Isolated cells were incubated in Ringer with zinc (0.1-100 microM). Taurine transport was done with 50 nM [3H]taurine or by isotopic dilution with taurine (0.001-1 mM) and 50 nM [3H]taurine. RESULTS: Zinc reduced the capacity of taurine transport without changes in affinity, and caused a noncompetitive inhibition of high affinity taurine transport, with an EC50= 0.072 microM. The mechanism by which zinc affects taurine transport is unknown at the present. CONCLUSIONS: There may be a binding site of zinc in the transporter that affects union or translocation of taurine, or possibly the formation of taurine-zinc complexes, rather than free zinc, could affect the operation of the transporter.
This article was published in J Biomed Sci
and referenced in Journal of Membrane Science & Technology