[Rapid inhibitory effect of glucocorticoids on peak of [Ca2+]i and PLC in airway smooth muscle].

Objective:In this study,we pretreated the mice ASMCs by dexemisone (Dex) within 10 min,to test the peak of [Ca2+]i and phospho-PLCβ (ser1105) in the cells by treated with Ach. Methods: The peak of [Ca2+]i was measured by Fura-2/AM methods and the phospho-PLCβ-ser1105 was by Western blot,and compared with dexemisone pretreated groups. Glucocorticoid receptor antagonist RU486 and the protein synthesis inhibitor cycloheximide groups were setted in our study. Results: Glucocorticoids (GCs) significantly decreased the resting values and peak of [Ca2+]i elevation and elevated the intracellular levels of phospho-PLCβ (ser1105) in 10 min. Neither the RU486 nor cycloheximide could alter the inhibitory effects of glucocorticoids stated above. Conclusion: Our results demonstrate that glucocorticoids exert rapid inhibitory effects. The series of signal changes in this process that restrain the peak of [Ca2+]i may be responsible for the rapid nongenomic inhibitory effects of GCs by reducing the activity of PLC.