Figure 2.

The effects of histamine on cytokine-induced (a) CXCL10 gene expression and (b) H1/H2 receptor involvement. Asthmatic (A) and nonasthmatic (NA) confluent serum-deprived ASM cells were left untreated or treated with the H1 or H2 receptor antagonists chlorpheniramine and ranitidine, respectively, for 45 minutes prior to and during stimulation with IL-1β or TNF-α. After 4 or 24 h stimulation cells were lysed and CXCL10 mRNA levels were measured using real-time RT PCR or CXCL10 in the culture medium quantified using ELISA, respectively. *P < 0.05 compared with (a) unstimulated cells (unstim) or (b) and (c) the cytokine control, ANOVA.