The effects of S(-)-, R(+)-, and racemic bupivacaine on lysophosphatidate-induced priming of human neutrophils

Local anesthetics modulate inflammatory responses and may therefore be potentially useful in mitigating perioperative inflammatory injury. The inflammatory modulating effects of S(-)-bupivacaine are not known. Therefore, we compared the effects of S(-)bupivacaine, R(+)-bupivacaine, and racemic bupivacaine on neutrophil function and receptor signaling. Priming (by lysophosphatidic acid [LPA]) and activation (by N-formylmethionine-leucyl-phenylalanine) of superoxide release by isolated human neutrophils was studied by using a cytochrome c-reduction assay. LPA receptor signaling in Xenopus oocytes was studied by using voltage clamp. All three local anesthetics were without effect on activation. S(-)-Bupivacaine inhibited priming more than did racemic bupivacaine; R(+)-bupivacaine was without effect. At 10(-4) M, S(-)- bupivacaine inhibited approximately 50%. Comparable results were obtained in our recombinant model, where S(-)-bupivacaine most effectively inhibited LPA signaling. Compared with racemic bupivacaine and other anesthetics, S(-)-bupivacaine appears particularly effective in suppressing neutrophil priming, a process responsible in part for the overactive neutrophil response.