[Change in the electrophysiological parameters of human oocytes in the process of maturation outside the body]

The dynamics of electrophysiological parameters (membrane potential--MP and resistance--R) of the human oocytes was studied during their in vitro maturation. The relationship was established between the changes of electrophysiological parameters and meiotic phases. The average value of MP of diplotene oocytes was 22.0 +/- 0.3 mV and that of R 2.0 +/- 0.5 mO. The membrane depolarization was observed upon the meiotic reinitiation. The MP of diakinesis--metaphase I oocytes amounted to 10.0 +/- 0.3 mV and R to 10.0 +/- 0.5 mO. At metaphase II the temporary membrane repolarisation was noted in some cases which, in some oocytes, was replaced by the increasing hyperpolarisation on the 2--3rd day of cultivation. The input membrane resistance increased on the 2--3rd day of cultivation.