氨对脑细胞胞浆游离钙含量的影响

THE EFFECT OF AMMONIA ON THE FREE CALCIUM CONTENT OF ISOLATED BRAIN CELLS

目的与方法 :采用Fura 2 /AM探针技术观察NH4 Cl对离体急性分离之Wistar乳鼠大脑细胞胞浆游离钙[Ca2 +]i 含量的影响。结果 :NH4 +浓度为 2 .5mmol/L时脑细胞内 [Ca2 +]i 含量升高。在一定范围内 ,随着NH4 +浓度的加大 ,细胞内Ca2 +持续升高。NH4 +的升钙作用主要被Nicardipine所阻断 ,其变化特征类以KCl。 结论 :NH4 +主要通过影响电压依赖性钙离子通道的开启而导致细胞内钙稳态失调。氨中毒时所引起的各种脑的功能 。

Aim and methods: The effect of ammonium chloride on the free calcium{[Ca 2+ ] i} content of isolated brain cell from newborn Wistar rats(25 d) were investigated by Fura2/AM probe techniques in SHIMADZU RF5000 SpectrofIuorophotometer (Japan).Results: The [Ca 2+ ] i, content in 2.5 mmol/L of ammoniumtreated cells was increased. The cytoplasmic [Ca 2+ ] i content raised continuously following the increase of ammonium concentration. The effect of NH 4+ could be blocked by Nicardipine, a kind of blocker for voltagegated calcium channel, which was similar to that ot KCI.Conclusion: NH 4+ might result in the calcium homeostasis imbalance of brain cells through interfering the voltagegated calcium channels. Variable dysfunction,metabolic alteration and structural abnormality in ammonia intoxication happened in acute or chronic hepatic dieases might be related to the intracelluar calcium homeostasis imbalance caused by hyperammonemia.