【作者】 张志红； 屈卫东； 陈国光； 蒋颂辉； 朱惠刚；

【Author】 Zhang Zhihong,Qu Weidong,Chen Guoguang,Jiang Songhui,et al. School of Public Health,Fudan University,Shanghai 200032,China

【机构】 复旦大学公共卫生学院； 中国水质监测中心； 上海市水质监测站；

【摘要】 目的探讨类毒素-A(ANTX-A)致神经元烟碱型乙酰胆碱受体激活和脱敏时胞内钙调信号的变化。方法用Flue-3-AM荧光法和发色底物法分别测定PC12细胞在激活和脱敏状态胞内钙离子浓度和钙离子-钙钙调蛋白依赖的蛋白磷酸酶(PP2B)活性。结果 PC12细胞在ANTX-A刺激时的激活、脱敏状态,胞内钙离子浓度都显著高于对照,(P<0.05),该作用能被L型电压敏感钙通道阻滞剂维拉帕米(VRP)减弱。而胞内PP2B活性在细胞激活时降低,在脱敏时,酶活性明显升高,呈剂量反-应关系和时间反应关系(P<0.05),且该作用可被烟碱型乙酰胆碱受体拮抗剂美加明(MEC)抑制。结论 ANTX-A激活和脱敏PC12细胞时,胞内钙离子浓度都显著增高,而PP2B活性激活时降低,脱敏时升高,提示胞内钙离子和PP2B可能参与调控ANTX-A诱导神经元烟碱受体激活和脱敏过程。更多还原

【Abstract】 Objective To investigate changes of the intracellular calcium regulative signals during the activation and desensitization of neural nicotinic acetylcholine receptor induced by anatoxin-A（ANTX-A）.Melhods The intracellular calcium concentration and the calcium-calmodulin dependent protein phosphatase calcineurin（CaN,PP2B） activity were determined by Fluo-3-AM fluorescence method and luminescence substrate method in the process of cell activation and desensitization.Results During the activation and desensitization of PC12 cells stimulated by ANTX-A,[Ca²⁺];raised obviously than that of the control group（P<0.05）.And it was decreased by L- voltage sensitive calcium channel（VSCC） inhibitor verapamil（VRP）.While the intracellular PP2B activity was lower than that of the control group during the activation,and was higher during the desensitization,and displayed dose response and time-dependent relation（P<0.05） that was blocked by nicotinic antagonist meeamylamine（MEC）.Conclusion During the activation and desensitization of PC12 cells evoked by ANTX-A,[Ca²⁺]_I was both increased obviously.PP2B activity was decreased in the activation and improved in the desensitization.It is suggested that[Ca²⁺]_i and PP2B may be involved in the intracellular signal transduction pathway of the activation and desensitization of neural micotinic receptors induced by ANTX-A.更多还原