Fig. 3. Time curve of the effect of CaM kinase inhibitor (KN62) and its inactive analogue (KN04) upon human sperm motility and viability. Immediately after selection with glass wool columns, motile sperm were resuspended in medium not supplemented with CaCl₂, and 60 µM KN62 () or KN04 () were added. After 30 minutes, aliquots were supplemented with CaCl₂ (final concentration: 2.5 mM) and cells were incubated for up to 18 hours in capacitating conditions. Aliquots incubated in medium not supplemented with CaCl₂ (–Ca²⁺, ) and in the absence of the inhibitors (+Ca²⁺, ) served as controls. The percentages of progressively motile (A) and live (B) cells after 1, 2, 4, 6 and 18-hour incubations were determined. The results are expressed as mean±s.e.m., n=7. *P<0.01 when compared with sperm motility under control conditions.