Interfering with the signaling pathway. (A) Changes in [Ca²⁺]_i and path curvature evoked by release of cGMP at t = 0 (dashed line) in the presence of 10 µM Niflumic acid. The cell displays small, rapid Ca²⁺ oscillations that entail similarly fast curvature oscillations (Pearson correlation, −0.17; mean Pearson correlation, −0.01 ± 0.28; n = 6). (B) Path curvature and dF_r/dt superimpose (Pearson correlation, 0.50; mean Pearson correlation, 0.48 ± 0.13; n = 6). (C) Swimming path of a sperm cell before (green) and after (red) cGMP release by a UV flash (black arrow and yellow bar) in the presence of 10 µM Niflumic acid. (D) Sperm accumulation in a Gaussian gradient of chemoattractant with and without Niflumic acid. Relative changes in the standard distance D_r of sperm around the center of the flash after release of resact (t = 0) without (blue) or with (red) 10 µM Niflumic acid are shown. Error bars denote SEM (12 experiments).