Changes of Intracellular Free Ca2+ in Macrophages Following N-Formyl Chemotactic Peptide Stimulation. Direct Measurement by the Loading of Quin 2

• Published in: Journal of biochemistry (Tokyo) 1984, Vol.96 (1), p.9-16
• Main Authors: HIRATA, Masato, HASHIMOTO, Toshihiko, HAMACHI, Takafumi, KOGA, Toshitaka
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Aminoquinolines; Analysis of the immune response. Humoral and cellular immunity; Animals; Biological and medical sciences; Biological Transport - drug effects; Calcium - metabolism; Chemotactic Factors - pharmacology; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Guinea Pigs; Immunobiology; In Vitro Techniques; Macrophages - drug effects; Macrophages - metabolism; N-Formylmethionine Leucyl-Phenylalanine - pharmacology; Organs and cells involved in the immune response; Spectrometry, Fluorescence
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a134834

The changes in the intracellu1a, free Ca2+ in guinea pig peritoneal macrophages induced by N-formyl chemotactic peptides were examined using a fluorescent Ca2+ indicator, quin 2. The ATP contents of quin 2-loaded macrophages were also examined. The intracellular free Ca2+ was immediately raised about 4-fold by the addition of chemotactic peptides both in the presence and absence of extracellular Ca2+ and returned to the basal level within 6 min. A mitochondrial uncoupler had no effect on basal free Ca2+ concentration and the increase in intracellular free Ca2+ induced by chemotactic peptides. A23187 increased the intracellular free Ca2+ concentration and minimized the increase by chemotactic peptides. Chiorpromazine also gradually increased the basal level, in agreement with our previous report that this drug induced Ca2+ release from the store sites. The results indicate that the increase in the intracellular free Ca2+ induced by chemotactic peptides is due to Ca2+ release from the membraneous store site(s), other than mitochondria. Extracellular Ca2+ was raised by the addition of a chemotactic peptide, when assayed inCa2+-free saline using guin 2. The second addition of the chemotactic peptide, after the intracellular free Ca2+ concentration had returned to the basal level, was ineffective. Recovery of the free Ca2+ change induced by chemotactic peptide was observed only when the macrophages were freshly incubated in Ca2+-containing saline for more than 20 min at 37°C. These results suggest that the Ca released from the store site(s) may be effluxed through the plasma membrane. Quin 2 loaded in macrophages may interfere with mitochondrial ATP synthesis.