Fig. 3.

Ca²⁺ channel blockers, dopamine antagonists and selective estrogen receptor modulators block endogenous NAADP-mediated Ca²⁺ signals.

A, exemplar Ca²⁺ signals, recorded using Fluo-4 from sea urchin egg homogenates pre-incubated with the indicated drug (100 μM) or DMSO (black traces) for ~1 min prior to stimulation with NAADP (1 μM).

B, concentration-effect relationships for blockade of NAADP responses by the various drugs (n = 3). Data are normalised to the NAADP response in the presence of DMSO.

C, summary data quantifying the effect of the drugs (100 μM) on Ca²⁺ response to NAADP versus cyclic ADP-ribose (n = 3). Data are normalised to the NAADP and cyclic ADP-ribose responses in the presence of DMSO.