Laboratorio de Neuroquímica, Centro Biofísica Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
Amino Acids. 2010 May;38(5):1429-37. doi: 10.1007/s00726-009-0357-1. Epub 2009 Sep 27.
Taurine and zinc exert neurotrophic effects. Zinc modulates Na(+)/Cl(-)-dependent transporters. This study examined the effect of zinc (ZnSO(4)) ex vivo and zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN) in vivo on [(3)H]taurine transport in goldfish retina. The effect of TPEN in vivo on taurine and zinc levels was determined. Isolated cells were incubated in Ringer with zinc (0.1-100 microM). Taurine transport was done with taurine (0.001-1 mM) and 50 nM [(3)H]taurine. Zinc (100 microM) noncompetitively inhibited taurine transport. TPEN was administered intraocularly and retinas extracted 3, 5 and 10 days later. Taurine was determined by HPLC (nmol/mg protein) and zinc by spectrophotometry ICP (mg/mg protein). Taurine and zinc levels decreased at 3 days and increased at 10 days after TPEN administration. At 10 days after intraocular TPEN, taurine transport affinity increased (K (s) = 0.018 +/- 0.006 vs. 0.028 +/- 0.008 mM). Apparently, zinc deficiency affects the taurine-zinc complex and taurine availability. The increased taurine uptake affinity by TPEN was possibly associated with a response to maximize retinal taurine content at low zinc concentration.
牛磺酸和锌具有神经营养作用。锌调节 Na(+)/Cl(-)依赖性转运体。本研究在金鱼视网膜离体和活体条件下，研究了锌（ZnSO(4)）和锌螯合剂 N,N,N',N'-四（2-吡啶甲基）乙二胺（TPEN）对[3H]牛磺酸转运的影响。体内 TPEN 对牛磺酸和锌水平的影响也进行了测定。分离的细胞在含锌（0.1-100 μM）的 Ringer 中孵育。用牛磺酸（0.001-1 mM）和 50 nM[3H]牛磺酸进行牛磺酸转运。100 μM 锌非竞争性抑制牛磺酸转运。TPEN 经眼内给药，3、5 和 10 天后提取视网膜。用 HPLC（nmol/mg 蛋白）测定牛磺酸，用 ICP 分光光度法（mg/mg 蛋白）测定锌。TPEN 给药后 3 天，牛磺酸和锌水平下降，10 天恢复。眼内给予 TPEN 10 天后，牛磺酸转运亲和力增加（K(s)=0.018±0.006 比 0.028±0.008 mM）。显然，锌缺乏会影响牛磺酸-锌复合物和牛磺酸的可用性。TPEN 增加牛磺酸摄取亲和力可能与在低锌浓度下最大限度地增加视网膜牛磺酸含量的反应有关。
