Osterrieder W, Yang Q F, Trautwein W
Pflugers Arch. 1982 Jul;394(1):85-9. doi: 10.1007/BF01108312.
The elementary conductance of the slow inward current channel in the rabbit sinoatrial node was measured by analysis of the current fluctuations. The preparations were voltage-clamped to -30 mV, where d infinity and f infinity of the slow inward current (Isi) intersect. In the presence of Ba, which increases Isi and decreases outward currents, a small steady-state component of Isi could be detected. The fluctuations of the current in 10 mM Ba were smaller due to the block of the outward channels. They were further reduced after the inhibition of Isi by the Ca channel blocker D600. The spectral power density distribution of the current fluctuations originating from Isi could be fitted at frequencies less than 30 Hz with a single Lorentzian which was attributed to the inactivation process. The corner frequency was 5.28 +/- 1.16 Hz (n = 10), corresponding to an average open time of the single channel of about 30 msec at -30 mV. The single channel conductance was determined to 6.50 +/- 3.15 pS (S.D., n = 10).
通过对电流波动的分析，测量了兔窦房结中慢内向电流通道的基本电导。将标本钳制在-30mV电压，此时慢内向电流（Isi）的d∞和f∞相交。在钡存在的情况下，钡增加Isi并减少外向电流，此时可以检测到Isi的一个小的稳态成分。由于外向通道被阻断，10mM钡溶液中电流的波动较小。在用钙通道阻滞剂D600抑制Isi后，波动进一步减小。源自Isi的电流波动的频谱功率密度分布在频率小于30Hz时可用单个洛伦兹曲线拟合，该曲线归因于失活过程。转折频率为5.28±1.16Hz（n = 10），对应于在-30mV时单通道的平均开放时间约为30毫秒。单通道电导测定为6.50±3.15pS（标准差，n = 10）。
