animal cell 4 article 4 calcium ionophore controlled study 4 female 4 fertilization 4 immunofluorescence 4 male 4 nonhuman 4 oocyte 4 priority journal 4 sperm 4 spermatozoon capacitation 4 unclassified drug 4 zona pellucida 4 Acrosome reaction 2 Calcium 2 Epididymis 2 Fertilization 2 Gamete biology 2 Male reproductive tract 2 Ovum 2 Rattus 2 Seminal vesicles 2 Sperm 2 Sperm capacitation 2 acrosome 2 acrosome reaction 2 caltrin 2 cell fusion 2