Pharmacological comparison of LTB4‐induced NADPH oxidase activation in adherent and non‐adherent guinea‐pig eosinophils

Abstract

Leukotriene B₄ (LTB₄) stimulation of guinea‐pig peritoneal eosinophils, induced a biphasic activation of the NADPH oxidase composed of a rapid (2=−6.31; PP1: pD₂=−5.50) and sustained (SB203580: pD₂=−6.50; PP1: pD₂=−5.73) phases. Similarly, the MAP kinase kinase‐1 inhibitor, PD098059 produced partial inhibition of the both phases of superoxide generation. The protein kinase C (PKC) inhibitors Ro‐31 8220, GF 109203X and Gö 6976 attenuated the rapid NADPH oxidase response (pD₂s=−6.10, −6.72, −6.15 respectively) and, to a lesser extent, (pD₂s=−5.54, −6.02, −6.51 respectively) the sustained phase. An inhibitor of phosphatidylinositol 3‐kinase (PtdIns 3‐kinase), wortmannin caused concentration dependent attenuation of the sustained (pD₂=−8.68) but not rapid phase of superoxide generation. In contrast, the syk kinase inhibitor, piceatannol abolished the rapid (pD₂=−6.43) but not sustained respiratory responses. This study demonstrates that LTB₄‐induced superoxide generation from adherent and non‐adherent eosinophils is mediated via both common (p38 MAP kinase, MEK‐1, PKC and the src kinases) and divergent intracellular pathways (syk kinases and PtdIns 3‐kinase). This suggests the possibility of therapeutic intervention to selective attenuate activation of adherent tissue eosinophils. British Journal of Pharmacology (2001) 134, 797–806; doi:10.1038/sj.bjp.0704314