DiPolo R, Caputo C, Bezanilla F
Proc Natl Acad Sci U S A. 1983 Mar;80(6):1743-5. doi: 10.1073/pnas.80.6.1743.
A voltage-dependent inward calcium current insensitive to tetrodotoxin has been measured in internally perfused or dialyzed squid giant axons. Sodium conductance was blocked by tetrodotoxin, and potassium conductance was irreversibly destroyed by the lack of potassium in the external and internal medium. Chloride conductance was eliminated by replacement of chloride with methylsulfonate. The calcium current was activated at about -40 mV and it peaked at about 0 mV. The peak inward current was 3 microA/cm2 when external Ca was 80 mM and 0.9 microA/cm2 in 8 mM Ca. In 80 mM Ca, the calcium current is turned on in less than 10 msec, and it does not decay appreciably for pulses up to 70 msec in duration. Barium can replace calcium, and cadmium blocks the calcium current.
在内部灌注或透析的枪乌贼巨大轴突中，已测量到一种对河豚毒素不敏感的电压依赖性内向钙电流。河豚毒素阻断钠电导，外部和内部介质中缺乏钾会不可逆地破坏钾电导。用甲磺酸盐替代氯离子可消除氯电导。钙电流在约 -40 mV 时被激活，在约 0 mV 时达到峰值。当外部钙浓度为 80 mM 时，内向电流峰值为 3 μA/cm²，在 8 mM 钙时为 0.9 μA/cm²。在 80 mM 钙中，钙电流在不到 10 毫秒内开启，对于持续时间长达 70 毫秒的脉冲，它不会明显衰减。钡可以替代钙，镉会阻断钙电流。
