Bourinet E, Nargeot J, Charnet P
CRBM, CNRS (UPR9008)-INSERM (U249), Montpellier, France.
Proc Biol Sci. 1992 Nov 23;250(1328):127-32. doi: 10.1098/rspb.1992.0140.
We have studied a fast inward current expressed in oocytes from one Xenopus laevis. This current was characterized as a sodium current. It was activated by depolarizations to -50 mV or higher, peaked within 3-5 ms, and then decayed following a mono-exponential timecourse. When clamped at different holding potentials, the current displayed voltage-dependent inactivation with a V0.5 of -51 mV. The channel responsible for this Na+ entry was blocked by tetrodotoxin with a K0.5 of 8 nM, and was resistant to block by lidocaine at concentrations up to 100 microM. The pharmacological similarities between neuronal and oocyte sodium channels suggest that the two channels share a conserved structure.
我们研究了一只非洲爪蟾卵母细胞中表达的一种快速内向电流。该电流的特性为钠电流。在去极化至-50 mV或更高时被激活，在3 - 5毫秒内达到峰值，然后按照单指数时间进程衰减。当钳制在不同的钳位电位时，电流表现出电压依赖性失活，其半数失活电压（V0.5）为-51 mV。负责这种钠离子内流的通道被河豚毒素阻断，其半数抑制浓度（K0.5）为8 nM，并且在浓度高达100 μM时对利多卡因的阻断具有抗性。神经元钠通道和卵母细胞钠通道之间的药理学相似性表明这两种通道具有保守的结构。
