Electrical membrane properties of the Xenopus laevis oocyte during progesterone-induced meiotic maturation☆

[摘要] Themembraneinputresistance(Rm),potential(Em),andcapacitance(Cm)offullygrownXenopusoocytesremovedfromtheirfollicleshavebeenmeasured.Beforehormonalmaturation,Rm,Em,andCmwerefoundtobe:1.86±0.63MΩ,−49±17mV,and11.9±4.3μF/cm2ofapparentsurfacearea.Long-termrecordingfromoocytesinthepresenceof1μMprogesteronerevealthatduringearlyGVBD(germinalvesiclebreakdown)themembranepotentialdepolarizedtoabout−10mV,theapparentspecificcapacitancedecreasedto1.5to3μF/cm2,andthemembraneresistancetransientlyincreasedbyafactorofabout3.Theseresultsindicatethatadecreaseinsurfacearea,atransientincreaseinmembraneresistance,andachangeintheionicmechanismsforthemembranepotentialoccurduringprogesterone-inducedmeioticmaturation.Thecontinuousmonitoringoftheseparametershasfurthershownthatthemajorchangesoccuratabout50to60%ofthetimefromprogesteroneapplicationtoGVBD,andthatatthesensitivitiesused,generally1.25mV/mm,nochangesareseenimmediatelyuponapplicationofthehormone.

[学科分类] 生物科学（综合）