牛磺酸对大鼠脑神经细胞内钙稳态的影响

EFFECT OF TAURINE ON CYTOSOLIC CALCIUM HOMEOSTASIS IN BRAIN NEURONS OF RATS

目的和方法 :利用激光扫描共聚焦显微镜和双波长荧光分光光度计 ,分别观察牛磺酸对无血清培养的单个海马神经细胞和分散的新生大鼠脑神经细胞内Ca2 +浓度 ([Ca2 +]i)的影响 ,并探讨牛磺酸调节神经细胞内钙稳态的作用机理。结果 :牛磺酸主要通过刺激细胞内钙库释放 ,在一定剂量范围内 (0 .0 2～ 6 .4mmol/L)使神经细胞[Ca2 +]i 轻微升高 ,在 0 .4mmol/L时的升钙作用最大 (升钙百分率为 12 .2 0 %± 1.2 4% )。在测定介质中加入钙离子载体A2 3187(10 μmol/L) ,使神经细胞内的钙离子浓度升高 ,若此时加入牛磺酸 (1.6mmol/L) ,则神经细胞内钙离子的浓度下降。结论 :牛磺酸对细胞内钙离子有双向调节作用 ,牛磺酸可能是通过对钙稳态的调节作用来阻止细胞内钙超载 ,保护神经细胞、并发挥其增强动物学习记忆等方面功能的。

Aim and Methods:To investigate the effect of taurine on cytosolic free calcium ([Ca 2+ ] i),one of the second messengers in signal transduction,in brain cells isolated neonatal rats detected by fluorespectrophotometer,and in the primary cultured single hippocampal cell detected by laser confocal microscope,respectively. Results:Taurine induced a rapid, dose-dependent increase in cytosolic calcium levels in suspension of neuronal cells,with the extracellular physiological Ca 2+ concentration.Taurine at the dose of 0.4 mmol/L exhi- bited its highest increase in cytosolic calcium(the increase percentage of Ca 2+ was 12.20%±1.24%).When we added A 23187 ,one of the Ca 2+ ionophore,to normal calcium containing media,the single neuronal cell[Ca 2+ ] i was increased but it was decrease as soon as 1.6 mmol/L taurine was added.Conclusion: Cytosolic calcium homeostasis can be adjusted by taurine,and the slightly increase cytosolic calcium in neuronal cells may be one of the major mechanism of taurine’s enhancing the memory and learning ability.