糖皮质激素快速抑制高钾离子诱导嗜铬细胞瘤细胞内游离钙浓度升高的作用及其特征  

EFFECT OF GLVCOCORTICOID ON [ca^(2+) ]I INDUCED BY HIGH-K^+ IN SINGLE PC12 CELLS AND ITS CHARACTERISTICS

作　　者：娄淑杰[1] 王晨光[2] 黄秀英 陈宜张[1] 

机构地区：[1]第二军医大学生理学教研室,神经科学研究所上海200433 [2]中国科学院发育生物学研究所开放实验室,北京100081

出　　处：《生理学报》1998年第5期563-569,共7页Acta Physiologica Sinica

基　　金：国家自然科学基金!No39330100

摘　　要：本研究应用钙离子特异荧光指示剂Fura－2／AM，使用Miracal影像系统（MiracalImageSystem）检测了糖皮质激素对高钾离子升高嗜铬细胞瘤细胞（PC12细胞）内游离钙浓度（[Ca2+]i）作用的影响。结果表明：（1）皮质酮抑制高钾离子诱导PC12细胞[Ca2+]i升高与其预处理细胞时间的长短有关，预处理3min时，皮质酮开始产生抑制作用；预处理5min时，其呈现的抑制作用最强；预处理25min时，抑制作用基本消失。（2）皮质酮在10－8～10－5mol／L范围内时可呈剂量-效应关系，抑制高钾离子诱导的PC12细胞[Ca2+]i升高，皮质团浓度为10－5mol／L时，其产生的抑制作用最大；在10－9mol／L时抑制作用不明显。（3）其它自体激素如皮质醇。地塞米松、孕酮、雌二醇、睾酮、醛固酮在浓度为10－5mol／L时，也能抑制高钾离子引起的PC12细胞[Ca2+]i升高，但在同一浓度时作用强度有所不同。胆固醇浓度为10－5mol／L时，对高钾离子诱导PC12细胞钙浓度升高没有抑制作用。在同一浓度时它们的作用强度顺序大致为：孕酮＝皮质醇＞地塞米松＞睾酮＞醛固酮＝雌二醇＞＞胆固醇。（4）在皮质酮浓度为10－5mol／L时不能抑制由细胞外无钙到有钙过程引起的PC12细胞[Ca2+]i升高。The effect of glucocorticoid on the increase of cytosolic free calcium [ Ca2+ j, )induced by high-K+ was investigated in pheochomocytoma PC12 cells. The aden restiltwas as follows: (l ) When the cells were preincubated at 37t for various time intervallin the presence of 10-5 moVL of corticosterone and stimulated with 55 mrnol/L KCI, anichbitory effect of conicosterone on b [ CaZ + ]. was observed in a bine-dependent mannerwith ~rnal effect at sib adn and no effect at 25th adn. (2) adn PC12 cells werepreincubated with various concentration of corticosterone at 37T for 5 adn, the inhibitoryeffect of corticosterone on A [ Ca2+ ]. induced by 55 rnmol/L KCI was concentrationdependent. The effect was found to be maximal at 10--5 moVL of colticosternne anddiSappeared at 10-9 moUL of corticosterone. (3 ) Other steroids such as coltisol,dexalnethasone, progesterone, testosterone, 17fyeshadiol and aldosterone allo ichbitedthe rise Of [ Ca2+ ], evoked by 55 mrnoVL KCI in PC12 cells to different extents, i. e., inthe ac Of P = F > Dex > T > kid = EZ. Cholesterol was ineffetive at the concentration uptO 10-s moUL for ichbiting [ Ca2+ ], evoked by 55 nunoVL KCI. (4) Corticosteronecould not inhibit the [ Ca2+ J, rise induced by changing the concenhation of exbeellularcalcium fIDm Ca2+ -able tO 3 nimoVL.

关 键 词：糖皮质激素 PC12细胞 高钾离子 FURA-2/AM 

分 类 号：Q577[生物学—生物化学]