Regulation of [Ca(2+)](i) oscillations and mitochondrial activity by various calcium transporters in mouse oocytes

Oocyte activation inefficiency is one of the reasons for female infertility and Ca(2+) functions play a critical role in the regulation of oocyte activation. We used various inhibitors of Ca(2+) channels located on the membrane, including sarcoplasmic/ endoplasmic reticulum Ca(2+)ATPases (SERCAs, the main Ca(2+) pumps which decrease the intracellular Ca(2+) level by refilling Ca(2+) into the sarcoplasmic reticulum), transient receptor potential (TRP) ion channel subfamily member 7 (TRPM7, a Ca(2+)/Mg(2+)-permeable non-selective cation channel), T-type Ca(2+) channels and calcium channel Orai1, to investigate their roles in [Ca(2+)](i) oscillation patterns and mitochondrial membrane potential during oocyte activation by real-time recording. Our results showed that SERCAs, TRPM7 and T-type Ca(2+) channels were important for initiation and maintenance of [Ca(2+)](i) oscillations, which was required for mitochondrial membrane potential elevation during oocyte activation, as well as oocyte cytoskeleton stability and subsequent embryo development. Increasing the knowledge of calcium transport may provide a theoretical basis for improving oocyte activation in human assisted reproduction clinics.