Calcium-activated cation nonselective current contributes to the fast afterdepolarization in rat prefrontal cortex neurons
Calcium-activated cation nonselective current contributes to the fast afterdepolarization in rat prefrontal cortex neurons
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DOI：
10.1152/jn.1997.78.4.1983
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发表时间：
1997-10-01
影响因子：
2.5
通讯作者：
Andrade, R
中科院分区：
文献类型：
--
作者：
HajDahmane, S;Andrade, R
大鼠前额皮质第五层锥体细胞在动作电位后表现出显着的快速后除极（fADP）。通过用镁替代细胞外钙、应用钙通道阻断剂镉以及将细胞内钙缓冲在接近生理水平，可以阻断这种 ADP。因此，这种快速的 ADP 似乎是由钙激活电流介导的。在河豚毒素存在的情况下记录的钙峰值后还观察到显着的 ADP。使用混合电流-电压协议记录该 ADP 的电流。在存在钾通道阻滞剂以及 E-CI 的情况下，可以观察到强 ADP。此外，ADP 下的电流随着亚阈值范围内的超极化而增加，并显示出接近 +30 mV 的外推反转电位。降低细胞外钠与细胞内钠的比例抑制了 ADP 下方的电流，并导致其反转电位发生超极化转变。我们得出结论，这些细胞表达钙激活的阳离子非选择性电流，其激活有助于 fADP 的产生。这种电流可能在确定皮层锥体细胞的放电特性方面发挥重要作用。
Pyramidal cells of layer V in rat prefrontal cortex display a prominent fast afterdepolarization (fADP) following an action potential. This ADP is blocked by replacing extracellular calcium with magnesium, by the application of the calcium-channel blocker cadmium, and by buffering intracellular calcium at near physiological levels. Thus this fast ADP appears mediated by a calcium-activated current. A prominent ADP is also observed following a calcium spike recorded in the presence of tetrodotoxin. The current underlying this ADP was recorded using a hybrid current-voltage protocol. A strong ADP could be observed in the presence of potassium channel blockers as well as at E-CI. Furthermore, the current underlying the ADP increased with hyperpolarization in the subthreshold range and displayed an extrapolated reversal potential near +30 mV. Reducing the ratio of extracellular to intracellular sodium inhibited the current underlying the ADP and caused a hyperpolarizing shift in its reversal potential. We conclude that these cells express a calcium-activated cation nonselective current whose activation contributes to the generation of the fADP. This current could play an important role in determining the firing properties of pyramidal cells in cortex.