Figure 11.

Partial antagonism of Ca²⁺ signalling in human neutrophils upon preincubation with 8-Ph-ADPR (5). Primary human PMN (polymorphonuclear neutrophils) were loaded with Fura-2/AM and analyzed by ratiometric Ca²⁺ imaging. Cells were stimulated by addition of 10 μM A5 peptide (A, gray line) or 1 μM fMLP (B, gray line). To determine the effect of 5 on fMLP or A5 peptide induced Ca²⁺ signalling, cells were preincubated with 100 μM of 5 for 15 min at rt (A,B black line). Data of single cells were synchronized to the first maximum after addition of A5 peptide or fMLP and represent mean values of Fura-2 ratio (primary y-axis). Corresponding [Ca²⁺]_i in nM are shown on secondary y-axis. The number of cells for each condition (n) is indicated in the inset legend.