Effect of rolipram and dibutyryl cyclic AMP on resequestration of cytosolic calcium in FMLP‐activated human neutrophils

• Published in: British journal of pharmacology Vol. 124; no. 3; pp. 547 - 555
• Main Authors: Anderson, R, Mahomed, A Goolam, Theron, A J, Ramafi, G, Feldman, C
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-1998; Nature Publishing
• Subjects: Adrenergic beta-Agonists - pharmacology; Adult; Albuterol - pharmacology; Biological and medical sciences; Bucladesine - pharmacology; Calcium - metabolism; calcium efflux; calcium influx; Calcium Radioisotopes; Cytosol - metabolism; dibutyryl cyclic AMP; elastase; Fluorescent Dyes; Fura-2; Humans; In Vitro Techniques; Medical sciences; N-Formylmethionine Leucyl-Phenylalanine - pharmacology; Neuropharmacology; neutrophils; Neutrophils - drug effects; Neutrophils - enzymology; Neutrophils - metabolism; Pharmacology. Drug treatments; Phosphodiesterase Inhibitors - pharmacology; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Pyrrolidinones - pharmacology; Rolipram; superoxide; Superoxides - metabolism; Theophylline - pharmacology; Human; 3',5'-Cyclic-nucleotide phosphodiesterase; Deactivation; Enzyme; Psychotropic; Cyclic AMP; Enzyme inhibitor; Esterases; Activation; Phosphoric diester hydrolases; In vitro; Hyperoxides; Rolipram; Hydrolases; Antidepressant agent; FMLP peptide; Neutrophil; Calcium Cations
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0701849

We have investigated the effects of the selective phosphodiesterase (PDE) type 4 inhibitor, rolipram (0.01–1 μM) on cytosolic Ca2+ fluxes in FMLP‐activated human neutrophils, as well as on superoxide production by, and release of elastase from, these cells.
Cytosolic Ca2+ 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 Ca2+ 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 45Ca2+, indicative of enhancement of resequestration of the cation by the endo‐membrane Ca2+‐ATPase.
Inhibition of superoxide production and elastase release was observed at concentrations of rolipram which accelerated the clearance of Ca2+ from the cytosol of FMLP‐activated neutrophils.
These effects of rolipram on FMLP‐activated Ca2+ fluxes, superoxide generation and elastase release were mimicked by pretreatment of neutrophils with dibutyryl cyclic AMP (0.5–4 mM), while theophylline (10–150 μM), a non‐specific PDE inhibitor, as well as the β2‐agonist, salbutamol, were less effective.
We conclude that rolipram deactivates FMLP‐stimulated human neutrophils by enhancement of cyclic AMP‐dependent resequestration of cytosolic Ca2+.