Warre R, Randall A
Neuroscience Research, SmithKline Beecham Pharmacaeuticals, New Frontiers Science Park (North), Essex, Harlow, UK.
Neurosci Lett. 2000 Nov 3;293(3):216-20. doi: 10.1016/s0304-3940(00)01531-7.
Using patch clamp methods we have investigated the deactivation properties of the T-type Ca(2+) channel generated by expression of the rat alpha(1I) subunit in HEK293 cells. The amplitude of the repolarisation-induced tail current was strongly correlated (R=0. 998) with the current amplitude immediately prior to repolarisation. The rate of deactivation was voltage-dependent between -120 mV (tau(deact)=0.9+/-0.0 ms) and -60 mV (tau(deac)=3.3+/-0.5 ms). Interestingly, the rate of deactivation observed at -80 mV was clearly dependent on the level of inactivation induced immediately prior to repolarisation, with greater inactivation producing significantly slower deactivation. In contrast, the rate of deactivation appeared completely independent of the level of steady-state inactivation. Together these data indicate the presence of a tight relationship between the recent induction of inactivation of this T-type channel and its subsequent rate of deactivation.
我们使用膜片钳方法研究了在HEK293细胞中表达大鼠α(1I)亚基所产生的T型Ca(2+)通道的失活特性。复极化诱导的尾电流幅度与复极化前的电流幅度高度相关（R = 0.998）。失活速率在-120 mV（τ(deact)=0.9±0.0 ms）至-60 mV（τ(deac)=3.3±0.5 ms）之间呈电压依赖性。有趣的是，在-80 mV观察到的失活速率明显取决于复极化前立即诱导的失活水平，失活程度越高，失活速度越慢。相比之下，失活速率似乎完全独立于稳态失活水平。这些数据共同表明，该T型通道最近诱导的失活与其随后的失活速率之间存在紧密关系。
