Single pulses of cytoplasmic calcium associated with phagocytosis of individual zymosan particles by macrophages

We have measured cytosolic free calcium levels (Ca++]i) in individual macrophages during the phagocytosis of single zymosan particles. We report here that the contact of a macrophage with zymosan results in a rapid transient elevation of Ca++]i. Each Ca++]i pulse is symmetrical lasting for up to 30 seconds. In contrast, macrophage spreading is associated with repetitive Ca++]i spiking occurring in salvos of up to four smaller spikes, each lasting for between 8 and 18 seconds. These qualitative and kinetic differences might suggest that the role of Ca++]i in phagocytosis is distinct from its role in spreading.