Effect of calcium on sperm motility of cauda epididymis in vitro

Experiments were performed to investigate the effect of calcium on percent motility of cauda epididymal spermatozoa in vitro. Epididymal luminal contents collected by micropuncture were immediately diluted with different concentrations of calcium chloride in KRB buffer. Percent motility was recorded at different time intervals at room temperature. Results revealed that there was an immediate effect of calcium on sperm motility. The maximum motility was attained only on addition of 10(-5)M calcium chloride in the buffer, whereas a higher or lower concentration than the above in the medium was inhibitory. Higher calcium levels maintained the sperm motility for a longer duration with a slow, time-dependent decrease than the lower concentrations where a faster depression in motility occurred. It is concluded that calcium at an appropriate level in the medium is essential for optimal sperm motility.