Slow Ca 2+ waves in large myeloid cells as a result of a diffusible cytosolic factor

In the work reported here evidence is provided that shows the slow wave of Ca 2+ large neonatal myeloid cells provoked by formyl‐Met‐Leu‐Phe was generated by spatially delayed Ca 2+ influx. Evidence is provided that the delay in Ca 2+ influx was the result of diffusion of a factor from the Ca 2+ storage site, which is responsible for Ca 2+ channel opening. The location of the Ca 2+ release site was correlated with a region near the nucleus, probably a specialized region of endoplasmic reticulum. It is proposed that similar mechanisms of Ca 2+ signaling occur in mature myeloid cells, such as neutrophils, but on a shorter time scale as a consequence of their smaller size. J. Leukoc. Biol. 57: 837–841; 1995.