“…Further, drugs that induce Ca ++ release from internal store (calcium ionophore A23187 (CI) and ionomycin) can also trigger meiotic resumption from diplotene arrest in mouse (Jones et al, ; Lefevre et al, ; Wakai et al, ), rat (Chaube et al, ), bovine (Boni et al, ), porcine (Fan et al, ), and human oocytes cultured in vitro (Lu et al, ). The Ca ++ channel blockers (verapamil and nifedipine) inhibit spontaneous resumption of meiosis in mouse (Homa, ), rat (Paleos and Powers, ; Yoo and Smith, ), porcine (Bae and Channing, ; Rozinek et al, ), and bovine oocytes cultured in vitro (Tosti et al, ). Previous study has revealed that increased Ca ++ oscillations within the oocyte trigger meiotic resumption from diplotene arrest (Fan et al, ).…”