Nusetti S, Urbina M, Lima L. Effects of zinc ex vivo on taurine uptake in goldfish retinal cells.
J Biomed Sci 2010;
17 Suppl 1:S13. [PMID:
20804587 PMCID:
PMC2994400 DOI:
10.1186/1423-0127-17-s1-s13]
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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 µM). 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 µM. 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.
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