Interstitial potential during propagation in bathed ventricular muscle.
Interstitial potential during propagation in bathed ventricular muscle.
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在沐浴的心室肌中传播期间的间质电位。
DOI：
10.1016/s0006-3495(91)82267-6
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发表时间：
1991
影响因子：
3.4
通讯作者：
BuchananJr,JW
中科院分区：
文献类型：
--
作者：
Knisley,SB;Maruyama,T;BuchananJr,JW
理论模拟表明，动作电位传播期间的间质电位（维斯）影响沐浴心室肌跨膜动作电位的测量。为了评价维斯的实验，我们获得了维斯和细胞内动作电位（维克）记录在不同深度的起搏豚鼠乳头肌浸泡在氧代台氏液。测定维斯记录的固有向下偏转的峰-峰幅度和最大dV/dt（dV/dtmax）。通过从相应的维克记录中减去每个维斯获得跨膜动作电位（TM），并将维克的零相去极化和动作电位足的测量值与TM的测量值进行比较。在大约54微米的穿透深度处，维斯的振幅和dV/dtmax为13 mV和-38 V/s。当深度增加到200 μ m时，这些参数增加到24 mV和-59 V/s（P <0.005），当深度进一步增加到390 μ m时，这些参数降低到16 mV和-38 V/s。由于不同深度处的维斯，维克将TM的相位零的dV/dtmax低估了20- 31%，这将降低从dV/dt获得的Na+电流的估计值。此外，维克将动作电位2-8 mV足的时间常数高估了48- 82%，这将使“有效”膜电容的估计值降低33- 45%。维斯对测量的这些影响可能会影响心室动作电位定量研究的结果。
Theoretical simulations have suggested that interstitial potential (Vis) during action potential propagation affects measurements of the transmembrane action potential in bathed ventricular muscle. To evaluate the Vis experimentally, we obtained Vis and intracellular action potential (Vic) recordings at various depths in paced guinea pig papillary muscles bathed in oxygenated Tyrode's solution. The peak-to-peak amplitude and the maximum dV/dt (dV/dtmax) of the intrinsic downward deflection of the Vis recordings were determined. The transmembrane action potential (TM) was obtained by subtracting each Vis from the corresponding Vic recording, and measurements for the phase zero depolarization and action potential foot of the Vic were compared with the measurements for the TM. At penetration depths of approximately 54 microns, the amplitude and dV/dtmax of the Vis were 13 mV and -38 V/s. When the depth was increased to 200 microns, these parameters increased to 24 mV and -59 V/s (P less than 0.005), and when the depth was further increased to 390 microns, the parameters decreased to 16 mV and -38 V/s. Because of the Vis at the various depths, the Vic underestimated dV/dtmax of phase zero of the TM by 20–31%, which would reduce estimates of Na+ current obtained from dV/dt. Also, the Vic overestimated the time constant of the 2–8 mV foot of the action potential by 48–82%, which would reduce estimates of the "effective" membrane capacitance by 33–45%. These influences of the Vis on measurements may affect results of quantitative studies of the ventricular action potential.