Pulsatile Ca2+ influx in human neutrophils undergoing CD11b/CD18 integrin engagement.
Rapid-time confocal scanning has demonstrated that neutrophils undergoing CDllb/CD18 integrin-dependent adhesion show repeated elevations in cytosolic free Ca2+ concentration, due to Ca2+ influx. The magnitude of each individual influx, compared to the previous one, depended upon the time between the two, and not upon the cytosolic Ca2+ concentration at the start of the influx. Influx events occurring less than 100 seconds after the previous Ca2+ rise were observed not to reach the concentration of the preceding peak, whilst events occurring later usually exceeded the magnitude of the previous Ca2+ concentration. This suggested temporary inactivation, followed by recovery, of the Ca2+ influx mechanism. In addition, Ca2+ influx was most likely to occur immediately following this recovery. The involvement of Ca2+ store release at the site of integrin engagement suggested that the cytoskeletal connection between the peripheral store and membrane was facilitating the signalling of Ca2+ influx.
Pettit
E J
EJ
Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff, United Kingdom.
Hallett
M B
MB
D000814:Aniline Compounds; D015703:Antigens, CD / Q000097:blood*; D018821:CD18 Antigens / Q000097:blood*; D002118:Calcium / Q000097:blood*; D002448:Cell Adhesion; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D016177:Macrophage-1 Antigen / Q000097:blood*; D009504:Neutrophils / Q000276:immunology / Q000502:physiology*; D013997:Time Factors; D014966:Xanthenes
D000814:Aniline Compounds; D015703:Antigens, CD; D018821:CD18 Antigens; D005456:Fluorescent Dyes; D016177:Macrophage-1 Antigen; D014966:Xanthenes; C059715:Fluo-3; D002118:Calcium