Fig. 4.

Secondary validation of candidates in sea urchin egg homogenate. A, Full concentration response curves resolving effects of selected primary screen candidates on Ca²⁺ release in sea urchin egg homogenates evoked by NAADP (70 nM). Current NAADP antagonists (PPADS, ned-19 and naringenin) are also included. IC₅₀ values for the entire dataset are provided in Table 1. B, Averaged peak Ca²⁺ release in the presence of drug (30μM, 5 min preincubation time) relative to vehicle controls, in response to EC₇₀ concentrations of NAADP (70 nM), cADPR (100 nM), or IP₃ (200 nM). C, Analysis of effects of all 18 candidates on specific ³²P-NAADP radioligand binding levels in the presence of drug (30μM), relative to vehicle controls. p-values: ** p < 0.01 relative to DMSO controls.