Potentiation by ATP of lipopolysaccharide-stimulated nitric oxide production in cultured astrocytes
Potentiation by ATP of lipopolysaccharide-stimulated nitric oxide production in cultured astrocytes
复制标题
DOI：
10.1016/s0306-4522(02)00804-7
复制
发表时间：
2003-03
期刊：
影响因子：
3.3
通讯作者：
K. Murakami;Yoichi Nakamura;Yukio Yoneda
中科院分区：
文献类型：
--
作者：
K. Murakami;Yoichi Nakamura;Yukio Yoneda
星形胶质细胞的功能变化深入参与各种中枢神经系统疾病的神经退行性过程。 ATP 在各种神经元损伤（例如脑缺血）期间释放，并可能控制星形胶质细胞的功能。我们研究了 ATP 对培养的大鼠胚胎星形胶质细胞中一氧化氮产生的影响。星形胶质细胞在体内受到脂多糖的刺激而不是病理激活。通过荧光测定培养基中积累的亚硝酸盐来评估一氧化氮的产生。通过蛋白质印迹分析诱导型一氧化氮合酶的表达。 ATP 可以增强 1 ng/ml 脂多糖诱导的一氧化氮生成，最大增强三到四倍；半有效浓度约为0.3 mM。在没有 ATP 的情况下，脂多糖对一氧化氮产生的半有效浓度约为 3 ng/ml；然而，在 1.5 mM ATP 存在的情况下，半有效浓度变为 0.3 ng/ml。其他几种 P2 受体激动剂（三磷酸尿苷、ADP、单磷酸腺苷、2'- 和 3'-O-（4-苯甲酰苯甲酰基）-ATP 和 2-甲硫基 ATP）显示出类似的增强作用，而拮抗剂 ATP-2',3'-二醛则显示出抑制作用。蛋白质印迹分析表明，添加 ATP 后，脂多糖诱导的一氧化氮合酶表达程度增加了数倍；半有效浓度约为0.5 mM。这些结果表明，细胞外 ATP 作为递质发挥着重要作用，并通过某种 P2 受体调节星形胶质细胞的功能，并且星形胶质细胞功能的这种变化与神经退行性过程的保护或加剧有关。
The functional changes of astrocytes are deeply involved in neurodegenerating processes of various CNS diseases. ATP is released during various neuronal damages such as brain ischemia and may control astrocyte functions. We examined the effect of ATP on the production of nitric oxide in the cultured astrocytes from rat embryo. The astrocytes were stimulated by lipopolysaccharide instead of pathological activation in vivo. Nitric oxide production was evaluated by the fluorometric assay of nitrite accumulated in the medium. The expression of inducible nitric oxide synthase was analyzed by Western blotting. Nitric oxide production induced by 1 ng/ml lipopolysaccharide was enhanced by ATP with maximal enhancement of three- to four-fold; a half-effective concentration was about 0.3 mM. In the absence of ATP, half-effective concentration of lipopolysaccharide on nitric oxide production was about 3 ng/ml; however, half-effective concentration shifted to 0.3 ng/ml in the presence of 1.5-mM ATP. Several other P2 receptor agonists (uridine triphosphate, ADP, adenosine monophosphate, 2′- and 3′-O - (4-benzoylbenzoyl)-ATP, and 2-methylthioATP) showed a similar enhancing effect, and an antagonist, ATP-2′,3′-dialdehyde, showed an inhibiting effect. Western blotting analysis revealed that the extent of lipopolysaccharide-induced expression of nitric oxide synthase increased several-fold by the addition of ATP; half-effective concentration was about 0.5 mM. These results suggest that the extracellular ATP plays an important role as a transmitter and regulates astrocyte functions via a certain P2 receptor and that such a change in astrocyte function is involved in either protection or aggravation in neurodegenerative processes.