Granulocytes without degranulation: neutrophil function in granule-depleted neutroplasts.
Neutroplasts, which are vesicles consisting of cytoplasm enclosed by plasmalemma, have been prepared and found to be incapable of degranulation in response to f-Met-Leu-Phe. However, neutroplasts generate superoxide anion in response to f-Met-Leu-Phe and PMA, and therefore, degranulation is not essential for superoxide anion generation. In addition, neutroplasts aggregate and show shape changes in response to f-Met-Leu-Phe and PMA, and thus degranulation is not essential for aggregation. Neutroplasts take up the carbocyanine dye DiOC6(3), thereby providing evidence for ionic gradients. Dye-loaded neutroplasts show fluorescence changes in response to a variety of stimuli. This response is not CN--inhibitable; therefore, activation of neutroplasts is associated with changes in membrane potential at the plasmalemma, suggesting a role for ion fluxes in the activation sequence for aggregation and superoxide anion generation.
D000838:Anions; D002232:Carbocyanines; D002449:Cell Aggregation; D003571:Cytochalasin B / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000502:physiology*; D006801:Humans; D008854:Microscopy, Electron; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D011523:Protoplasts / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D013481:Superoxides / Q000378:metabolism
D000838:Anions; D002232:Carbocyanines; D013481:Superoxides; D003571:Cytochalasin B; C007392:3,3'-dihexyl-2,2'-oxacarbocyanine; D009240:N-Formylmethionine Leucyl-Phenylalanine