Figure 3.

Effect of the cell permeant, non-hydrolysable cyclic AMP analogue (a) dibutyryl cyclic AMP and the cyclic AMP-elevating agents (b) forskolin and (c) cholera toxin on the release of eosinophil-activating cytokines from human airway smooth muscle cells stimulated by IL-1β (1 ng ml⁻¹) for 24 h. Data are expressed as a per cent of the control response to IL-1β alone and represent mean±s.e.mean of duplicate values from independent experiments using cells cultured from six to seven different donors, cell passages 3 – 5. ^*P<0.05, ^**P<0.01 ^***P<0.001 compared to control by Bonferroni's t-test. NS P>0.05 by ANOVA.