used. Sperm motility was activated in a Makler chamber (depth 10 μm,
volume of 20 μl) which was cooled to 4 °C. Hundred microliters 4 °C
sperm motility-activating saline solution and 2 μl sperm suspension
were mixed in the chamber. The chamber was closed with a cover slip,
whereby excess amount of diluted semen was drained off and
transferred into an inverse phase contrast microscope where the
motility was recorded on videotapes (magnification 200×).