['Lysophosphatidic acid (LPA) is an intercellular phospholipid mediator with a variety of actions that suggest a role in stimulating inflammatory responses. We therefore studied its actions on neutrophil (PMN) motility and respiratory burst. Because local anesthetics (LA) inhibit LPA signaling and attenuate PMN responses, we also investigated the effects of LA on these actions. Chemotaxis of human PMNs under agarose toward LPA (10(-10)-10(-3) M) was studied, with and without 1 h prior incubation in lidocaine (10(-9)-10(-4) M). Priming as well as activating effects of LPA on PMNs were measured using a cytochrome-c assay of superoxide anion (O2-) production. PMNs were incubated with lidocaine, tetracaine, or S-(-) ropivacaine (all at 10(-6)-10(-4) M) for 10 min or 1 h to assess interference with LPA signaling. LPA demonstrated chemoattractive effects towards human PMNs; this effect was concentration-dependently attenuated by lidocaine. LPA alone did not activate PMNs. However, it acted as a priming agent. LA in clinically relevant concentrations decreased (O2-) production induced by LPA/N-formylmethionine-leucyl-phenylanaline. LPA acts as a chemoattractant and priming agent; however, it does not activate PMNs. LA, in clinically relevant concentrations, attenuate chemotactic and metabolic responses as a result of LPA. These results may explain the antiinflammatory effect of local anesthestics.'] Do local anesthetics attenuate lysophosphatidic acid-induced priming in human neutrophils?