地塞米松快速抑制气道平滑肌内游离钙升高实验初探

Dexemisone rapid inhibitory effect on peak of [Ca^2＋] i in airway smooth muscle

目的 通过对平滑肌细胞行地塞米松快速预处理,拟证实糖皮质激素对平滑肌细胞内游离钙离子浓度[Ca^2＋]i升高有快速抑制作用.方法 原代培养的大鼠平滑肌细胞,比较不同浓度地塞米松预处理后10 min与对照组之间游离钙上升情况的区别.利用Fura-2/AM显微荧光检测技术,检测肌细胞内[Ca^2＋]i在受到激动剂刺激后的浓度变化;同时设立RU486及CHX对照组,排除基因组作用在该反应中的影响.结果 地塞米松温浴10 min,能够明显降低Ach引起的气道平滑肌细胞内[Ca^2＋]i峰值.以上反应均不能被RU486和CHX影响或者逆转.结果 地塞米松能够通过非基因组作用快速抑制Ach引起的气道平滑肌细胞内[Ca^2＋]i浓度升高.

Objective To prove GC can affect the airway smooth muscle cell CASMC） contraction by depreased the peak of [Ca2＋ ]i in the cells directly rapidly. Methods Pretreat the mice ASMC by Dex within 10 min,test the peak of [Ca2＋]i in the cells by treated with Ach. And we set RU486 and CHX groups to eliminate the genomic action of Dex. Results We found GC significantly decreased the resting values and peak of [Ca2＋]i elevation induced by agonist in 10 min. Neither the glucocorticoid receptor antagonist RU486 nor the protein synthesis inhibitor cycloheximide could alter the inhibitory effects of glucocorticoids stated above. Conclusions Our results demonstrate that glucocorticoids exert rapid inhibitory effects on ASMC. The signal changes in this process that restrain the peak of [Ca2＋ ]i may be responsible for the rapid nongenomic inhibitory effects of GC.