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Fluo 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 0 5 ) ,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 0 5 ) ,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。
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). Methods 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, [Ca 2+] i 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 mecamylamine(MEC). Conclusion During the activation and desensitization of PC12 cells evoked by ANTX-A, [Ca 2+] I was both increased obviously. PP2B activity was decreased in the activation and improved in the desensitization. It is suggested that [Ca 2+] 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.
出处
《卫生研究》
CAS
CSCD
北大核心
2004年第3期275-278,共4页
Journal of Hygiene Research
基金
国家高科技研究发展计划 ("863计划")专项经费资助(No .2 0 0 2AA60 1 1 30 )
