Figure 6.

KB-R7943 mesylate blocks suNCKX activity. (A) KB causes Ca²⁺ influx. KB was added to fura-2-loaded sperm in ASW at the arrow. The final concentration of KB in μM is shown on the right. (B) KB blocks Na⁺-dependent Ca²⁺ efflux. Fura-2-loaded sperm were prepared as in Fig. 5A. Sperm were mixed with various concentrations of KB (final μM shown on right) 2 min before addition of an equal volume of ASW at the arrow. (C) KB blocks K⁺-dependent Ca²⁺ influx. Fura-2-loaded sperm were diluted into Li⁺ solution plus 10 mM CaCl₂ with various concentrations of KB (μM final on right) 2 min before the addition of 10 mM KCl at the arrow. Experiments were repeated three times.