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Effect of rolipram and dibutyryl cyclic AMP on resequestration of cytosolic calcium in FMLP‐activated human neutrophils
Author(s) -
Anderson R,
Mahomed A Goolam,
Theron A J,
Ramafi G,
Feldman C
Publication year - 1998
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0701849
Subject(s) - rolipram , superoxide , chemistry , cytosol , elastase , phosphodiesterase , phosphodiesterase inhibitor , calcium , biochemistry , medicine , enzyme , organic chemistry
We have investigated the effects of the selective phosphodiesterase (PDE) type 4 inhibitor, rolipram (0.01–1 μ M ) on cytosolic Ca 2+ fluxes in FMLP‐activated human neutrophils, as well as on superoxide production by, and release of elastase from, these cells. Cytosolic Ca 2+ fluxes were measured by use of fura‐2 spectrofluorimetry in combination with a radiometric procedure that enables distinction between net efflux and influx of the cation. Superoxide production and elastase release were measured by lucigenin‐enhanced chemiluminescence and a colorimetric procedure, respectively. Pretreatment of neutrophils with rolipram did not affect the FMLP‐activated release of Ca 2+ from intracellular stores, but was associated with dose‐related acceleration of the rate of decline in fura‐2 fluorescence and with decreased efflux, as well as store‐operated influx of 45 Ca 2+ , indicative of enhancement of resequestration of the cation by the endo‐membrane Ca 2+ ‐ATPase. Inhibition of superoxide production and elastase release was observed at concentrations of rolipram which accelerated the clearance of Ca 2+ from the cytosol of FMLP‐activated neutrophils. These effects of rolipram on FMLP‐activated Ca 2+ fluxes, superoxide generation and elastase release were mimicked by pretreatment of neutrophils with dibutyryl cyclic AMP (0.5–4 m M ), while theophylline (10–150 μ M ), a non‐specific PDE inhibitor, as well as the β 2 ‐agonist, salbutamol, were less effective. We conclude that rolipram deactivates FMLP‐stimulated human neutrophils by enhancement of cyclic AMP‐dependent resequestration of cytosolic Ca 2+ .