[Electrophysiological study of frog eggs at different stages of development. III) Ionic currents activated by intense hyperpolarization and depolarization of the oocyte at the final stage of vitellogenesis].
In addition to K-selective channels, two kinds of voltage-dependent channels are present in the membrane of full-grown frog oocytes: 1) non-selective channels, activated by hyperpolarizing steps to potentials more negative than -80, -90 mV; 2) cationic channels, activated by depolarizing steps to potentials more positive than +30, +40 mV. The former are related to the inward rectification; the latter could contribute to the outward rectification of the I/V relationship. Therefore the membrane potential in full-grown oocytes tends to be maintained at a constant value due to the changes of permeability that follow possible potential variations occurring in both directions.
D000818:Animals; D004594:Electrophysiology; D005260:Female; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials; D009865:Oocytes / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011893:Rana esculenta; D014818:Vitellogenesis
D007473:Ion Channels; D011188:Potassium
Studio elettrofisiologico dell'uovo di rana a vari stadi di sviluppo. III). Correnti ioniche attivate da intense iperpolarizzazioni e depolarizzazioni dell'oocita allo stadio finale della vitellogenesi.