Slow Ca2+ 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 Ca2+ large neonatal myeloid cells provoked by formyl-Met-Leu-Phe was generated by spatially delayed Ca2+ influx. Evidence is provided that the delay in Ca2+ influx was the result of diffusion of a factor from the Ca2+ storage site, which is responsible for Ca2+ channel opening. The location of the Ca2+ release site was correlated with a region near the nucleus, probably a specialized region of endoplasmic reticulum. It is proposed that similar mechanisms of Ca2+ signaling occur in mature myeloid cells, such as neutrophils, but on a shorter time scale as a consequence of their smaller size.