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Relationships between phosphoinositide metabolism, Ca 2+ changes and respiratory burst in formyl‐methionyl‐leucyl‐ phenylalanine‐stimulated human neutrophils
Author(s) -
Rossi F.,
Bianca V.Delia,
Grzeskowiak M.,
De Togni P.,
Cabrini G.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80270-2
Subject(s) - respiratory burst , phenylalanine , chemistry , metabolism , biochemistry , neutrophile , amino acid , in vitro
The relationships between the changes of cellular Ca 2+ the activation of phosphoinositide turnover and the functional responses induced by the stimulus‐receptor interactions in neutrophils are matter of controversy. By measuring the concentration dependency of different formyl‐leucyl‐methionyl‐phenylalanine (FMLP)‐induced changes, the following values of ED 50 were found: 1.6 and 0.8 nM for the rise in [Ca 2+ ] i monitored with Quin‐2, in the presence and absence of exogenous Ca 2+ respectively; 20 nM for the activation of phosphoinositide metabolism, monitored as change in the 32 P i of phosphatidate; 14 nM for membrane‐bound Ca 2+ mobilization, monitored with chlorotetracycline (CTC); 34 nM for 45 Ca 2+ influx and 32 nM for the respiratory burst. Furthermore, low dose of FMLP causes an increase in [Ca 2+ ] i in absence of activation of breakdown of phosphatidylinositol, phosphatidylinositol 4‐monophosphate and phosphatidylinositol 4,5‐biphosphate monitored as changes in [ 3 H]glycerol radioactivity. The results clearly demonstrate that the increase in [Ca 2+ ] i , due to the release from intracellular stores, is not caused by the breakdown of phosphatidylinositides. On the other hand, the data of the similarity of ED 50 are compatible with an involvement of phosphoinositide response in the release of membrane bound Ca 2+ , monitored with CTC, and in the 45 Ca influx and in the respiratory burst.