The effect of dexamethasone on the contraction of isolated guinea-pig tracheal smooth muscle in vitro

The effect of Dex on isolated tion was studied in vitro.CaCl2 and histamine caused significant tracheal smooth muscle contraction and PD was 3.9 and 5.92 respectively.After incubated with Dex, the doseresponse curve of CaCl2 and His was significantly depressed was PD’and 4. 74 and 6. 67. Dex could also inhibited isoguinea-pig tracheal smooth muscle contraclated tracheal strips contraction induced by Ach 3×10-6 mol·L-1 and PGF2a 3 mmol·L-1. IC50 were 2.4×10-5 mol· L-1 and 4.26×10-4 mol· l-1. Dex had significant dilated effect on tracheal smooth muscle.