• Biomedical Science Letters
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• v.4 no.1
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• pp.27-33
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• 1998

This study has been designed in order to examine a physiological role of $Ca^{2+}$ which has been known as an essential factor for capacitation, to confirm whether the enzyme activity of $Ca^{2+}$-ATPase on capacitation is important or not, and to clarify relationship between various levels of the $Ca^{2+}$ concentration and $Ca^{2+}$-ATPase which has been known to be an important factor of the plasma membranes. In the present study applying quercetin, a $Ca^{2+}$-ATPase inhibitor, the enzymatic effect of $Ca^{2+}$-ATPase on capacitation was found to be remarkable: a significant increase of the transition from the original type (type A) to the type B and the type AR of the spermatozoa. This finding suggests that $Ca^{2+}$-ATPase plays an important role in the efflux and the influx of the $Ca^{2+}$ which has been known to be an essential factor the capacitation and acrosome reaction, and that the inhibitory action of the $Ca^{2+}$-ATPase might be a prerequsite step toward the acrosome reaction. The conclusion reached can be deduced as follows: increment of the intracelluar $Ca^{2+}$ concentration occurred by controlling the slope of $Ca^{2+}$ concentration through $Ca^{2+}$-ATPase activities in both the intra- and extracelluar fluid may be an important procedure for capacitation and acrosome reaction, and ultimately for fertilization of the spermatozoa and the ova.