CATSPER channels are not required for the ATP-induced [Ca2+]
rise. (A) Dose-responses of ATP-induced [Ca2+]i rises in the sperm head of wild-type (WT) mouse. (B) Peak amplitudes of ΔF/F0 induced by 0.1 mM ATP in WT and Catsper1 null (Mut) sperm. (C) Representative recordings of the time course of ATP (1 mM) -induced fluorescence changes in the principal piece (PP1), midpiece (MP1) and head, in a WT sperm. Like the ones induced by Ca2+ ionophore (10 μM ionomycin), the ATP-elicited [Ca2+]i increases started simultaneously in all subregions (D, n = 8). The locations of the subregions were defined as in Figure 3.