Changes in membrane potential of human granulocytes antecede the metabolic responses to surface stimulation
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- H. M. Korchak
- Department of Medicine, Division of Rheumatology, New York University School of Medicine, New York, New York 10016
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- Gerald Weissmann
- Department of Medicine, Division of Rheumatology, New York University School of Medicine, New York, New York 10016
抄録
<jats:p> Human granulocytes (polymorphonuclear leukocytes) exposed to surface stimuli [e.g., immune complexes, concanavalin A (Con A)] generate O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> , undergo a respiratory burst, and secrete lysosomal enzymes. To study the earliest reaction of ligands with surface receptors of granulocytes, purified cells were exposed to bovine serum albumin-anti-albumin complexes (Fc receptors) or Con A (glycoprotein receptors). The membrane potential (ΔΨ) was measured by distribution of the lipophilic cation [ <jats:sup>3</jats:sup> H]triphenylmethyl phosphonium ion. The Nernst equation yielded a resting ΔΨ of -26.7 mV. Beginning within 10 sec after exposure to the antigen-antibody complex or to Con A, the cells responded with a rapid hyperpolarization → depolarization → slow hyperpolarization. Even when phagocytosis was inhibited by cytochalasin B, the triphasic response was obtained: evidence for <jats:italic>surface</jats:italic> interaction. The hyperpolarization response anteceded O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> generation (continuous recording) by at least 20-30 sec. O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> generation in response to immune complexes was stimulated by Ca <jats:sup>2+</jats:sup> whereas ΔΨ remained unchanged; lack of Ca <jats:sup>2+</jats:sup> in the medium did not inhibit the ΔΨ response. Dissociation of membrane hyperpolarization from subsequent metabolic responses (O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> generation) was also found in the presence of steroids (hydrocortisone, methylprednisolone), which inhibited O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> generation but did <jats:italic>not</jats:italic> inhibit the ΔΨ response to antigen-antibody complex. Because O <jats:sub>2</jats:sub> · <jats:sup>-</jats:sup> generation could be stimulated (Ca <jats:sup>2+</jats:sup> ) or depressed (steroids) without affecting ΔΨ, the data suggest that ΔΨ is involved in primary triggering of phagocytic cells and that metabolic stimulation is a secondary consequence of ligand-receptor interactions. </jats:p>
収録刊行物
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- Proceedings of the National Academy of Sciences
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Proceedings of the National Academy of Sciences 75 (8), 3818-3822, 1978-08
Proceedings of the National Academy of Sciences
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詳細情報 詳細情報について
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- CRID
- 1362825894496658688
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- NII論文ID
- 30016267388
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- ISSN
- 10916490
- 00278424
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