A LOW VOLTAGE-ACTIVATED, FULLY INACTIVATING CA-CHANNEL IN VERTEBRATE SENSORY NEURONS
A LOW VOLTAGE-ACTIVATED, FULLY INACTIVATING CA-CHANNEL IN VERTEBRATE SENSORY NEURONS
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DOI：
10.1038/310501a0
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发表时间：
1984-01-01
期刊：
影响因子：
64.8
通讯作者：
LUX, HD
中科院分区：
文献类型：
--
作者：
CARBONE, E;LUX, HD
可兴奋膜中的钙通道对许多细胞功能至关重要。最近对一些脊椎动物神经元的突发放电模式的分析表明，它们的功能状态的变化是由Ca电导控制的，该电导在静息膜电位（- 50至- 60 mV）时大部分失活，但在细胞膜的调节超极化后被激活。在这里，利用小鸡和大鼠的感觉神经元，我们提供了一种具有时间和电压依赖特性的新型钙通道的证据，这可能是钙电导失活行为的原因。当膜电位在- 50和+10 mV之间时，该通道的打开持续3-6 ms，并且往往快速连续发生。该通道的失活表现为长时间的去极化电压步骤带来的延长和最终完全关闭。该通道与更常见的Ca通道共存于孤立的膜斑块中，Ca通道对保持电位的变化不太敏感，并且显示出相当短的平均寿命和较小的电流。
Calcium channels in excitable membranes are essential for many cellular functions. Recent analyses of the burst-firing mode of some vertebrate neurones1–3suggest that changes in their functional state are controlled by a Ca conductance that is largely inactivated at resting membrane potentials (−50 to −60 mV), but becomes activated following a conditioning hyperpolarization of the cell membrane. Here, using chick and rat sensory neurones, we present evidence for a new type of Ca channel with time- and voltage-dependent properties which is probably responsible for the inactivation behaviour of the Ca conductance. At membrane potentials between −50 and +10 mV, openings of this channel last 3–6 ms and tend to occur in rapid succession. Inactivation of this channel is indicated by prolonged and eventually complete closures brought about by long-lasting depolarizing voltage steps. This channel coexists in isolated membrane patches with the more common Ca channel4which is less sensitive to changes in holding potential and shows a considerably shorter average life time and smaller currents.