Although A23187 is widely used for the activation of oocytes in many animals, the effectiveness is different among species. In the present study, nuclear activation rates were still low even when the concentration was increased to 100 ц,М. Studies in cattle with either ethanol or A23187 indicate that the activation rates are dependent upon the age of oocytes. Also in cattle, the activation rates of oocytes were increased by culture of the oocytes in media containing the protein synthesis inhibitor cycloheximide. However, according to the study by Hagen et al., oocyte age-dependent activation of pig oocytes was not observed by electrical pulse. The possibilities of oocyte age-dependent activation by A23187 and/or by the combination of A23187 and cycloheximide for the activation of pig oocytes remain to be determined. ventolin inhaler
Different media have been used for the activation of pig oocytes by A23187, such as medium 199 with fetal calf serum, modified Whitten’s medium with BSA, and PBS. A concentration-dependent activation was not observed when the medium used was PBS. However, in the present study, we used an IVF medium (mTBM) as the oocyte activation medium in an effort to simulate fertilization conditions more closely.