Abstract
The initial kinetics of agonist-evoked rises in the cytosolic Ca2+ concentration [Ca2+]i were investigated in fura-2-loaded human neutrophils by stopped-flow fluorimetry. The rises in [Ca2+]i evoked by chemotactic peptide (fMet-Leu-Phe), platelet-activating factor and ADP all lagged behind agonist addition by 1-1.3 s. Lag times were not significantly different in the presence and in the absence of external Ca2+. Stimulation of the cells in the presence of extracellular Mn2+ resulted in a quench of fluorescence with a similar lag time to [Ca2+]i rise. The delay in onset of the rise in [Ca2+]i evoked by fMet-Leu-Phe was dependent on concentration, becoming longer at lower concentrations of agonist. These results indicate that both the agonist-evoked discharge of the intracellular Ca2+ stores and the generation of bivalent-cation influx lag behind agonist-receptor binding in neutrophils. Both pathways thus appear to be mediated by indirect mechanisms, rather than by a directly coupled process such as a receptor-operated channel. The temporal coincidence of the onset of store discharge with the commencement of bivalent-cation influx suggests that the two events may be causally linked.
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- Andersson T., Dahlgren C., Pozzan T., Stendahl O., Lew P. D. Characterization of fMet-Leu-Phe receptor-mediated Ca2+ influx across the plasma membrane of human neutrophils. Mol Pharmacol. 1986 Nov;30(5):437–443. [PubMed] [Google Scholar]
- Hallam T. J., Jacob R., Merritt J. E. Influx of bivalent cations can be independent of receptor stimulation in human endothelial cells. Biochem J. 1989 Apr 1;259(1):125–129. doi: 10.1042/bj2590125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korchak H. M., Rutherford L. E., Weissmann G. Stimulus response coupling in the human neutrophil. I. Kinetic analysis of changes in calcium permeability. J Biol Chem. 1984 Apr 10;259(7):4070–4075. [PubMed] [Google Scholar]
- Lew P. D., Monod A., Waldvogel F. A., Pozzan T. Role of cytosolic free calcium and phospholipase C in leukotriene-B4-stimulated secretion in human neutrophils. Comparison with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine. Eur J Biochem. 1987 Jan 2;162(1):161–168. doi: 10.1111/j.1432-1033.1987.tb10556.x. [DOI] [PubMed] [Google Scholar]
- Merritt J. E., Jacob R., Hallam T. J. Use of manganese to discriminate between calcium influx and mobilization from internal stores in stimulated human neutrophils. J Biol Chem. 1989 Jan 25;264(3):1522–1527. [PubMed] [Google Scholar]
- Merritt J. E., Rink T. J. Rapid increases in cytosolic free calcium in response to muscarinic stimulation of rat parotid acinar cells. J Biol Chem. 1987 Apr 15;262(11):4958–4960. [PubMed] [Google Scholar]
- Nasmith P. E., Grinstein S. Are Ca2+ channels in neutrophils activated by a rise in cytosolic free Ca2+? FEBS Lett. 1987 Aug 31;221(1):95–100. doi: 10.1016/0014-5793(87)80359-9. [DOI] [PubMed] [Google Scholar]
- Pollock W. K., Rink T. J., Irvine R. F. Liberation of [3H]arachidonic acid and changes in cytosolic free calcium in fura-2-loaded human platelets stimulated by ionomycin and collagen. Biochem J. 1986 May 1;235(3):869–877. doi: 10.1042/bj2350869. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pozzan T., Lew D. P., Wollheim C. B., Tsien R. Y. Is cytosolic ionized calcium regulating neutrophil activation? Science. 1983 Sep 30;221(4618):1413–1415. doi: 10.1126/science.6310757. [DOI] [PubMed] [Google Scholar]
- Prentki M., Wollheim C. B., Lew P. D. Ca2+ homeostasis in permeabilized human neutrophils. Characterization of Ca2+-sequestering pools and the action of inositol 1,4,5-triphosphate. J Biol Chem. 1984 Nov 25;259(22):13777–13782. [PubMed] [Google Scholar]
- Sage S. O., Merritt J. E., Hallam T. J., Rink T. J. Receptor-mediated calcium entry in fura-2-loaded human platelets stimulated with ADP and thrombin. Dual-wavelengths studies with Mn2+. Biochem J. 1989 Mar 15;258(3):923–926. doi: 10.1042/bj2580923. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sage S. O., Reast R., Rink T. J. ADP evokes biphasic Ca2+ influx in fura-2-loaded human platelets. Evidence for Ca2+ entry regulated by the intracellular Ca2+ store. Biochem J. 1990 Feb 1;265(3):675–680. doi: 10.1042/bj2650675. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sage S. O., Rink T. J. The kinetics of changes in intracellular calcium concentration in fura-2-loaded human platelets. J Biol Chem. 1987 Dec 5;262(34):16364–16369. [PubMed] [Google Scholar]
- von Tscharner V., Deranleau D. A., Baggiolini M. Calcium fluxes and calcium buffering in human neutrophils. J Biol Chem. 1986 Aug 5;261(22):10163–10168. [PubMed] [Google Scholar]
- von Tscharner V., Prod'hom B., Baggiolini M., Reuter H. Ion channels in human neutrophils activated by a rise in free cytosolic calcium concentration. 1986 Nov 27-Dec 3Nature. 324(6095):369–372. doi: 10.1038/324369a0. [DOI] [PubMed] [Google Scholar]