Silent calcium channels generate excessive tail currents and facilitation of calcium currents in rat skeletal myoballs.
Silent calcium channels generate excessive tail currents and facilitation of calcium currents in rat skeletal myoballs.
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沉默的钙通道会产生过多的尾电流并促进大鼠骨骼肌球中的钙电流。
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
R. Penner
中科院分区：
文献类型：
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作者：
A. Fleig;R. Penner
1.采用全细胞膜片钳记录研究了新生大鼠骨骼肌球培养物中由强且持久的条件去极化诱发的Ca 2+电流和过量Ca 2+尾电流的易化。2.配对脉冲易化和过度尾电流显示出相同的电压依赖性，在+30 mV以上的条件电位下变得突出。3.招募过多的尾电流和促进发生相同的时间依赖性（时间常数（τ），约200毫秒至约1秒），加速与去极化强度的调节脉冲。4.在调节和测试脉冲之间的复极化期间，Ca 2+电流易化的恢复具有时间和电压依赖性。在更负的复极化电位下，易化Ca 2+电流募集的时间窗显著变窄（tau：在-100 mV下约为10 ms，但在0 mV下约为1.5 ms）。5.无论是省略内部ATP，也不灌注的细胞与蛋白激酶A（PKI）的肽抑制剂有显着影响钙电流的便利，虽然内部灌注ATP γ S缓慢抑制约30%的便利电流。在对照条件下，外用ryanodine或咖啡因可选择性地显著抑制易化Ca 2+电流约30 - 40%。6.我们建议，Ca 2+电流和过度的尾电流的便利化是一个共同的机制与兰尼碱受体的后果。
1. Whole‐cell patch‐clamp recording were employed to study facilitation of Ca2+ currents and excessive Ca2+ tail currents evoked by strong and long‐lasting conditioning depolarizations in skeletal myoballs cultured from newborn rats. 2. Paired‐pulse facilitation and excessive tail currents showed the same voltage dependence, becoming prominent at conditioning potentials above +30 mV. 3. Recruitment of excessive tail currents and facilitation occurred with the same time dependence (time constant (tau), approximately 200 ms to approximately 1 s), accelerating with the depolarization strength of conditioning pulses. 4. Reversal of Ca2+ current facilitation during the repolarization period between conditioning and test pulses was time‐ and voltage dependent. The time window of recruitment of facilitated Ca2+ currents narrowed considerably at more negative repolarization potentials (tau: approximately 10 ms at ‐100 mV, but approximately 1.5 at 0 mV). 5. Neither omission of internal ATP nor perfusion of the cells with the peptide inhibitor of protein kinase A (PKI) had significant effects on Ca2+ current facilitation, although internal perfusion with ATP gamma S slowly suppressed the facilitation currents by about 30%. External application of either ryanodine or caffeine under control conditions selectively and significantly suppressed the facilitated Ca2+ currents by about 30‐40%. 6. We propose that facilitation of Ca2+ currents and excessive tail currents are consequences of a common mechanism linked to ryanodine receptors.
DOI：
10.1073/pnas.91.24.11492
发表时间：
1994-11-22
影响因子：
11.1
作者：
JOHNSON, BD;SCHEUER, T;CATTERALL, WA
通讯作者：
CATTERALL, WA