$Ca^{2+}$-ATPase Role in the Capacitation and Acrosome Reaction Assessed by a Chlortetracycline Fluorescence Assay

Chlortetracycline Fluoresence 분석을 통한 수정능 획득 과정에서의 $Ca^{2+}$-ATPase 역할

It has been reported that the $Ca^{2+}$-ATPase and the $Ca^{2+}-Na^+$ exchanger play an important role for the regulation of intracellular $Ca^{2+}$ in somatic cells, the $Ca^{2+}$-ATPase located in the plasma membrane helps the $Ca^{2+}$ concentration in maintain low $[Ca^{2+}]_i$. Roldan & Fleming reported that the spermatozoan $Ca^{2+}$-ATPase plays an important role in the capacitation and acrosome reaction. We used to assess $Ca^{2+}$ changes by chlortetracycline (CTC) patterns in the capacitation and acrosome reaction of human and hamster spermatozoa. In the present study applying quercetin which has been known as an ATPase antagonist, the enzymatic effect of $Ca^{2+}$-ATPase on capacitation and acrosome reaction was found to be remarkable: a significant increase of the transformation from the original type to the B type and the AR type of spermatozoa. This finding suggests that $Ca^{2+}$-ATPase play an important role in the efflux and the influx of the $Ca^{2+}$ which have been known to be an essential factor for the capacitation and acrosome reaction, and that the inhibitory action of the $Ca^{2+}$-ATPase might be a prerequsit step toward the capacitation and acrosome reaction. In conclusion, this study suggest the considerable evidence as follows: the increment of the intracellular $Ca^{2+}$ concentration occurred by controlling the slope of $Ca^{2+}$ concentration through $Ca^{2+}$-ATPase activites in both the intracellular and extracellulr fluid may be important procedures for the capacitation and the acrosome reaction, and finally for fertilization of the sperm and ovum.