THE EFFECT OF NIFEDIPINE, A CALCIUM-CHANNEL BLOCKER, ON HUMAN SPERMATOZOAL FUNCTIONS

In vitro addition of 0.1-100 mum of a calcium channel blocker, Nifedipine, resulted in a significant non-competitive inhibition in the uptake of Ca++. The activity of Ca++-dependent ATPase enzyme was also decreased. Motility of the spermatozoa was significantly arrested following incubation with different doses of the drug at 37-degrees-C for different durations. The pattern of motility changed within two hours from rapid and linear progression to slow or sluggish linear or non-linear movement and finally to non-progressive motility or even immotility. Scanning electron microscopic studies revealed disruptive changes in the head as well as tail region and coiling of spermatozoa after Nifedipine treatment. An increase in the formation and release of malonyldialdehyde was observed following Nifedipine addition in a dose-dependent fashion. The membrane cholesterol and phospholipid contents were considerably lowered in the treated samples. The potential of such calcium channel blocking agent in the designing of male contraceptive programme is discussed.