Ca2+-activated K+ (BK) channel inactivation contributes to spike broadening during repetitive firing in the rat lateral amygdala
Ca2+-activated K+ (BK) channel inactivation contributes to spike broadening during repetitive firing in the rat lateral amygdala
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DOI：
10.1113/jphysiol.2003.050120
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发表时间：
2003-10-15
影响因子：
5.5
通讯作者：
Sah, P
中科院分区：
文献类型：
--
作者：
Faber, ESL;Sah, P
在许多神经元中，动作电位序列显示出频率依赖性展宽。这种展宽是由于 K+ 电流的电压依赖性失活导致的，这有助于动作电位复极化。在不同的神经元细胞类型中，这些 K+ 电流已被证明要么缓慢失活延迟整流器型电流，要么快速失活 A 型电压门控 K+ 电流。最近的研究结果表明，由大电导 BK 型通道介导的 Ca2+ 依赖性 K+ 电流的失活也有助于尖峰展宽。在这里，我们使用急性切片中的全细胞记录，检查外侧杏仁核投射神经元的尖峰加宽。尖峰展宽与频率相关，并且可以通过短暂的超极化来逆转。通过阻断电压门控 Ca2+ 通道和 BK 通道可以减少这种增宽。相比之下，高浓度的 4-氨基吡啶 (4-AP) 或 α-树毒素不会阻止展宽。我们得出的结论是，虽然 BK 型 Ca2+ 激活的 K+ 通道的失活有助于外侧杏仁核神经元尖峰展宽，但另一种尚未识别的外向电流的失活也发挥了作用。
In many neurons, trains of action potentials show frequency-dependent broadening. This broadening results from the voltage-dependent inactivation of K+ currents that contribute to action potential repolarisation. In different neuronal cell types these K+ currents have been shown to be either slowly inactivating delayed rectifier type currents or rapidly inactivating A-type voltage-gated K+ currents. Recent findings show that inactivation of a Ca2+-dependent K+ current, mediated by large conductance BK-type channels, also contributes to spike broadening. Here, using whole-cell recordings in acute slices, we examine spike broadening in lateral amygdala projection neurons. Spike broadening is frequency dependent and is reversed by brief hyperpolarisations. This broadening is reduced by blockade of voltage-gated Ca2+ channels and BK channels. In contrast, broadening is not blocked by high concentrations of 4-aminopyridine (4-AP) or alpha-dendrotoxin. We conclude that while inactivation of BK-type Ca2+-activated K+ channels contributes to spike broadening in lateral amygdala neurons, inactivation of another as yet unidentified outward current also plays a role.