Release of calcium from membranes and its relation to phagocytotic metabolic changes: A fluorescence study on leukocytes loaded with chlortetracycline

A fluorescent probe chlortetracycline was used to monitor the mobilization of intracellular divalent cations of leukocytes. When the chlortetracycline-loaded cells were stimulated with cytochalasin D or $\text{E. coli}$, a fluorescence change ascribable to the release of calcium from the intracellular hydrophobic environment was observed. The dose-response curve of the fluorescence change and that of the superoxide release of the cells were very similar. An intracellular calcium antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate inhibited both metabolic and fluorescence changes in parallel. A supposition that an intracellular mobilization of calcium ions is stimulating the metabolic change was supported.