Rapid inhibitory effect of glucocorticoids on peak of Ca2+i and PLC in airway smooth muscle / 中国应用生理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>In this study, we pretreated the mice ASMCs by dexamethasone (Dex) within 10 min, to test the peak of [Ca2+]i and phospho-PLCbeta (ser1105) in the cells by treated with Ach.</p><p><b>METHODS</b>The peak of [Ca2+]i was measured by Fura-2/AM methods and the phospho-PLCbeta-ser1105 was by Western blot, and compared with dexamethasone pretreated groups. Glucocorticoid receptor antagonist RU486 and the protein synthesis inhibitor cycloheximide groups were settled in our study.</p><p><b>RESULTS</b>Glucocorticoids (GCs) significantly decreased the resting values and peak of [Ca2+]i elevation and elevated the intracellular levels of phospho-PLCbeta (ser1105) in 10 min. Neither the RU486 nor cycloheximide could alter the inhibitory effects of glucocorticoids stated above.</p><p><b>CONCLUSION</b>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.</p>