Fig. 1.

Inhibition of substance P (SP)-induced IL-8 production by test compounds. A549 cells stably transfected with tachykinin 1 receptor (Tacr1) were treated with test compounds for 30 min and then with 100 nM substance P for 4 h. IL-8 in cell culture supernatants was measured by ELISA. Baseline IL-8 levels were low in untreated cells (▴) and increased with substance P treatment (●). Most test compounds did not inhibit the substance P-induced increase in IL-8 production (black squares), but a minority appeared to cause significant inhibition (gray squares).