Effect of cytochalasin B on intracellular free calcium concentration in human polymorphonuclear leukocytes after repeated stimulation with n-formyl-methionyl-leucyl-phenylalanine.
Cytochalasin B can influence various functions of human polymorphonuclear leukocytes, including chemotaxis, lysosomal enzyme release, and reactive oxygen species generation. In this study we investigated the effect of cytochalasin B on the increase in intracellular free calcium concentration after three consecutive additions of 10(-7) M N-formyl-methionyl-leucyl-phenylalanine. The interval between stimulations was 5 min. Intracellular free calcium concentration was monitored using the fluorescent calcium indicator FURA-2AM. Cytochalasin B (3.3 micrograms/ml) added 60 s before the cell stimulation enhanced all three polymorphonuclear leukocyte calcium responses by increasing the N-formyl-methionyl-leucyl-phenylalanine-induced calcium influx from the extracellular space. Cytochalasin B increased the peak intracellular free calcium concentration and elevated the plateau phase level, but had no influence on its shape. In addition, pretreatment with cytochalasin B of polymorphonuclear leukocytes suspended in low calcium medium restored their capacity to respond to a third stimulation with N-formyl-methionyl-leucyl-phenylalanine. Finally, in resting cells cytochalasin B caused a moderate increase in intracellular free calcium concentration which was independent of extracellular calcium.
Nowak
D
D
Department of Pneumology and Allergology, Medical University of Lodz, Poland.
Bialasiewicz
P
P
Antczak
A
A
Krol
M
M
Piasecka
G
G
D000328:Adult; D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D003571:Cytochalasin B / Q000494:pharmacology*; D005260:Female; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D006801:Humans; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000737:chemistry / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism*
D005456:Fluorescent Dyes; C049925:fura-2-am; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium; D016257:Fura-2