To study the relevance of e tra cellular Ca2, capacitated sperm were thing either pre incubated for 10 min with 8 mM EGTA or added at the same time as SIZP. All the above inhibitors were procured from Sigma Aldrich Inc. Statistical analysis The results pertaining to SIZP mediated induction of acrosome reaction are presented as mean SEM and statistical analysis was done by comparing the means of the medium control vehicle control and e perimental sets or within two e perimental groups by using paired Students t test Wilco on signed rank test. A value of p 0. 05 was considered to be sta tistically significant. Results SIZP induces acrosomal e ocytosis in capacitated human sperm in a dose dependent manner A significant increase in the induction of acrosomal e o cytosis of capacitated human sperm was observed with a concomitant increase in number of zonae equivalent used per reaction, as compared to PBS.

As low as 1 zona equivalent was able to induce statistical significant induction of acrosome reaction in capacitated human sperm. However, no further increase in acrosomal e o cytosis was observed with SIZP preparation from more than 5 zonae per reaction. Subsequently, 5 zonae equivalent SIZP was used in all e periments. Capaci tated sperm prepared from 6 different donors on incu bation with optimized concentration of human SIZP showed a significant increase in induction of acrosome reaction. T type VOCCs are responsible for SIZP mediated induction of acrosome reaction subsequent to an initial increase in i An increase in i, after coming in contact with ZP, is a prerequisite for induction of acrosomal e ocytosis in mammalian sperm.

In the present study, SIZP was also able to elicit an increase in i after incu bating with fluo 3 AM labelled capacitated human sperm. To decipher the type of VOCCs playing an important Carfilzomib role in human SIZP mediated increase in initial i surge as well as subsequent induction of acrosome reaction, pharmacological inhibitors for L and T type VOCCs were employed. Prior incubation of fluo sellectchem 3 AM labelled capacitated human sperm with Pimozide inhibited the SIZP mediated initial increase in isurge, whereas Verapamil failed to do so. To further assess the importance of these VOCCs, induction of acrosome reaction in capacitated human sperm was quantitated after incubation with SIZP in presence or absence of pharmacological inhibitors of L or T type specific VOCC.