Fig. 2. Concentration curve of CaM kinase inhibitors effect upon human sperm motility and viability. Immediately after selection using glass wool columns, motile sperm were resuspended in medium not supplemented with CaCl₂, and in the presence or absence of the CaM kinase inhibitors KN62 () or KN93 (); or their inactive analogues KN04 () and KN92 () at the following final concentrations: 1, 3, 10, 30, 60, 100 µM. After 30 minutes, aliquots were supplemented with CaCl₂ (final concentration: 2.5 mM) and cells were incubated for 18 hours in capacitating conditions. Aliquots incubated in medium not supplemented with CaCl₂ (– Ca²⁺, ), in the absence of the inhibitors (+ Ca²⁺, ), or in the presence of 0.5% DMSO (DMSO, ) served as controls. The percentages of progressively motile (A) and live (B) cells were determined. The results are expressed as mean±s.e.m., n=6. *P<0.01 when compared to sperm motility under all other conditions.