Fig. 2. L-alanine or L-serine stimulates chemotactic migration in mouse neutrophils. (A) Fura-2 loaded neutrophils were stimulated with L-alanine (100 mM), L-serine (100 mM), or WKYMVm (1 μM). The relative intracellular calcium concentrations are expressed as fluorescence ratios. (B) Neutrophils were stimulated with L-alanine (100 mM) or L-serine (100 mM) for 0, 2, 5, 10, and 30 min. The levels of phosphorylated ERK or p38 MAPK were measured by Western blot analysis. The data represents three independent experiments (A and B). (C) Various concentrations (0, 0.1, 1, 10, or 100 mM) of L-alanine or L-serine were used for the chemotaxis assay (C). Vehicle or PTX (1 μg/ml) pretreated cells were subjected to the chemotaxis assay with 100 mM of L-alanine, 100 mM of L-serine, or 100 nM of WKYMVm (D). The number of migrated cells was determined by counting in a high-power field (400×). Data are presented as the mean±SEM of triplicate experiments. *P＜0.05, **P＜0.01, ***P＜0.001, compared with the vehicle control (C and D).