title: [Electrophysiological study of frog eggs at different stages of development. I) Membrane potential and I/V relationship in the oocyte at the final stage of vitellogenesis].
abstract: Variations of [K+]o have been found to influence the membrane potential in frog full-grown oocytes at a greater extent than other modifications in extracellular medium composition; however, the relationship between membrane potential and [K+]o was far from that expected for an ideal K electrode. The I/V relationship, as determined in current clamp conditions, displays an evident "inward-going" rectification at potentials more negative than -80, -90 mV as well as an evident "outward-going" rectification at potentials more positive than -20, -10 mV, thus suggesting the presence of voltage-dependent channels in this membrane. In the linearity range of the I/V relationship, Rm was found to be about 3 + 15 K omega cm2 and Cm about 20 + 30 microF/cm2.
mesh_terms: D000818:Animals; D004594:Electrophysiology; D005260:Female; D008564:Membrane Potentials; D009865:Oocytes / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011893:Rana esculenta; D012621:Seasons; D014818:Vitellogenesis
chemical_list: D011188:Potassium
vernacular_title: Studio elettrofisiologico dell'uovo di rana a vari stadi di sviluppo. I) Potenziale di membrana e relazione I/V nell'oocita allo stadio finale della vitellogenesi.