SODIUM CURRENT IN SINGLE MYOCARDIAL MOUSE CELLS
SODIUM CURRENT IN SINGLE MYOCARDIAL MOUSE CELLS
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DOI：
10.1007/bf00585418
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发表时间：
1985-01-01
影响因子：
4.5
通讯作者：
NILIUS, B
中科院分区：
文献类型：
--
作者：
BENNDORF, K;BOLDT, W;NILIUS, B
成年小鼠的形态学完整的单个心肌细胞显示长度为132 ± 100 μ m。20 μ m，宽度为21 ± 1 μ m。5 μ m，高度为10 ±。4 μ m（均为平均值±。SD），呈砖状。使用1吸移管方法对这些单细胞进行电压钳位。电容电流τ的确定时间常数= 35 .+-. 14 μ s非常短。串联电阻rs、膜电阻rm和膜电容cm计算为192 ± 1。48 k Ω，6.1 .+-. 11 M Ω，186 .+-. 92 pF（均为平均值±。SD）。假设单位膜的比电容为1 μ F/cm 2，则膜的总面积为1.86 × 10 - 6。10-4 cm 2，得到比膜电阻Rm为1，134 Ω cm 2。电压箝位的建立时间为30 μ s。Na电流的TTX[河豚毒素]阻断描述为1：1结合，KD值为1.4 × 10 - 6。10-6 M.使用降低的细胞外钠浓度，在-40 mV和-30 mV之间的电压下，最大Na电流在25 nA和40 nA之间。在+20 mV和+30 mV之间的电流以向外的方向反转。内向电流由m3 h模型近似。激活时间常数从-60 mV时的0.7 ms降低到+20 mV时的0.12 ms。失活时间常数福尔斯从-60 mV时的9.1 ms降至+20 mV时的0.6 ms。稳态灭活h.infin.其特征在于半最大值VH = 76.1 ±。4.3 mV和斜率参数s = 6.3 ±. 1.1 mV（平均值±）SD）。500 ms的预脉冲持续时间对于真实的稳态失活是必不可少的。稳态激活m.infin.和失活h.infin.它们彼此重叠，从而限定了在-65 mV处的最大窗口电流。
Morphologically intact single myocardial cells of the adult mouse show a length of 132 .+-. 20 .mu.m, a width of 21 .+-. 5 .mu.m, and a height of 10 .+-. 4 .mu.m (all mean .+-. SD) and are brick-like in shape. A 1 suction pipette method is used for voltage clamp of those single cells. The determined time constant of capacitive current .tau. = 35 .+-. 14 .mu.s is very short. Series resistance rs, membrane resistance rm, and membrane capacity cm are calculated to be 192 .+-. 48 k.OMEGA., 6.1 .+-. 11 M.OMEGA., and 186 .+-. 92 pF (all mean .+-. SD), respectively. Assuming the specific unit membrane capacitance of 1 .mu.F/cm2, a total membrane area of 1.86 .times. 10-4 cm2 is determined yielding a specific membrane resistance Rm of 1,134 .OMEGA.cm2. Settling time of voltage clamp is 30 .mu.s. TTX[tetradotoxin]-block of Na current is described by 1:1 binding with a KD value of 1.4 .times. 10-6 M. Using a reduced extracellular sodium concentration the maximum Na current is between 25 and 40 nA at voltages between -40 and -30 mV. Currents of between +20 and +30 mV reverse in an outward direction. Inward currents are approximated by a m3h model. The time constant of activation decreases from 0.7 ms at -60 mV to 0.12 ms at +20 mV. The time constant of inactivation falls from 9.1 ms at -60 mV to 0.6 ms at +20 mV. Steady state inactivation h.infin. is characterized by the half maximum value VH = 76.1 .+-. 4.3 mV and the slope parameter s = 6.3 .+-. 1.1 mV (mean .+-. SD). A prepulse duration of 500 ms is essential for real steady state inactivation. Steady state activation m.infin. and inactivation h.infin. overlap each other defining a maximum window current at -65 mV.