Effect of hemodialysis on intracellular calcium in human polymorphonuclear neutrophils.

Hemodialysis (HD) leads to neutrophil activation depending on the membrane material used. Calcium plays a major role in PMN function and metabolism. A rise of cytosolic free calcium [Ca2+]i is an important intracellular messenger for neutrophils. In this study we measured intracellular resting Ca2+ and the chemotactic peptide FMLP-stimulated intracellular Ca2+ during HD using membranes made of polysulfone and polymethylmethacrylate (PMMA). Also, we investigated the effect of continuous infusion of nifedipine in a dose of 18 micrograms/kg/h during HD with PMMA. Only HD with PMMA causes an increase of both resting and FMLP-stimulated [Ca2+]i after 30 min of starting HD. Polysulfone did not affect [Ca2+]i. Continuous infusion of nifedipine during HD with PMMA completely inhibited these changes of [Ca2+]i. Although the existence of voltage-sensitive calcium channels has not been proved, the present data provide further indirect evidence either for the existence of calcium channels or for a mechanism of action that is independent of antagonism.