[Electrophysiological study of the frog egg at various stages of development. IV. Changes associated with the maturation process].
The I/V relationship of frog oocytes is markedly modified following maturation, lacking the mature unfertilized egg cell membrane of K-selective channels and the leakage being strongly reduced. The only kind of voltage-dependent channels still present in this membrane are activated by depolarizing steps to potentials more positive than 30-40 mV; the current flowing through these channels is carried at least partly by Na+. At difference with the immature oocyte, where several ionic mechanisms are oriented to maintain the membrane potential at a constant level, the mature egg-cell admits considerable voltage deflections. The observed variations in membrane properties could be of importance in allowing the maturation process and/or in preparing the mature egg-cell to successful fertilization.
D000818:Animals; D004594:Electrophysiology; D005260:Female; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials; D009865:Oocytes / Q000254:growth & development / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011898:Ranidae / Q000502:physiology; D012964:Sodium / Q000378:metabolism
D007473:Ion Channels; D012964:Sodium; D011188:Potassium
Studio elettrofisiologico dell'uovo di rana a vari stadi di sviluppo. IV) Modificazioni associate al processo della maturazione.