Figure 1.

Concentration-response curves of Ca²+ signals in single intact T-lymphocytes microinjected with NAADP⁺. Jurkat T-lymphocytes were loaded with Fura2/AM and Ca²⁺ was measured as detailed in Materials and Methods. Cells were injected as described in Materials and Methods in the presence of 1 mM extracellular Ca²⁺. Data are presented as overlays of single tracings of individual cells (left). The right shows the corresponding averages from these measurements (number of cells displayed, n = 5–17). As a control, vehicle buffer without NAADP⁺ was injected (A and B). The time points of microinjection are indicated by arrows.