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