Fig. 1.

Structure and activity of selected GPCR agonists. A, chemical structures of CCK-1 receptor agonist A-71623 and bombesin-related receptor BB₁ and BB₂ antagonists PD176252 and PD168368. B, human neutrophils were treated with 300 nM PD176252 or PD168368, 20 μM A-716235, 5 nM fMLF (positive control), or 1% DMSO (negative control), and Ca²⁺ mobilization was monitored for the indicated times (arrow indicates when treatment was added). Arrow indicates time of treatment addition. C, human neutrophils were treated with the indicated concentrations of PD168368, PD176252, A-716235, and fMLF (all in micromolar), and MPO release was determined as described under Materials and Methods. The data are presented as mean ± S.D. of triplicate samples. In B and C, the data are from one experiment that is representative of three independent experiments.