Neutrophil hyperpolarization in response to a chemotactic peptide

摘要: The chemotactic peptide formylmethionyl-leucyl-phenylalanine (fMLP), at concentrations below 10(-9) M, elicits a sustained increase in the human neutrophil's membrane potential within 10 s of its addition. This hyperpolarization, detected with fluorescent cationic potentiometric probes, 3,3'-dipentyloxacarbocyanine (diO-C5-(3)), and 1,1'-dipropyl-3,3,3',3'-tetramethylindocarbocyanine iodide (diI-C3-(3)), anionic probe bis-(1,3-diethylthiobarbituric)trimethine oxonol (bis-oxonol), is immediately followed by large depolarization when [fMLP] greater than M. By extracellular substitution sodium ions potassium or choline pretreatment cells ionophores, we report here that hyperpolarization primarily dependent on an intact ion gradient accompanied concurrent acidification cytoplasm (approximately 0.05 pH unit) Although latter occurs simultaneously large, transient cytosolic Ca2+ 10(-10) it without detectable less neither affected nor initiated antagonist tert-butyloxycarbonyl-methionyl-leucyl-phenylalanine, whereas completely inhibited. Neutrophils isolated from patients X-linked chronic granulomatous disease exhibit normal hyperpolarizations increases response to peptides but no oxidative burst. appears earlier ontogeny differentiating myeloid precursor either rise response. Together, these findings indicate transmembrane one earliest events neutrophil peptides, coinciding temporally cytoplasmic H+ preceding burst activity.