Effects of potassium concentration on firing patterns of low-calcium epileptiform activity in anesthetized rat hippocampus: Inducing of persistent spike activity
Effects of potassium concentration on firing patterns of low-calcium epileptiform activity in anesthetized rat hippocampus: Inducing of persistent spike activity
复制标题
钾浓度对麻醉大鼠海马低钙癫痫样活动放电模式的影响：诱导持续尖峰活动
DOI：
10.1111/j.1528-1167.2006.00499.x
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发表时间：
2006-04-01
期刊：
影响因子：
5.6
通讯作者：
Durand, DM
中科院分区：
文献类型：
--
作者：
Feng, ZY;Durand, DM
目的：低钙高钾溶液在体内外均可引起癫痫样发作。此外，在癫痫样持续状态活动期间，脑组织中[K+]（o）的浓度增加，[Ca 2 +]o的浓度降低。因此，我们测试的假设，持久的持续尖峰活动，类似于癫痫持续状态的模式之一，可以产生由高钾，低钙溶液中的海马invivo.Methods：人工脑脊液灌注在表面上暴露的左背侧海马麻醉大鼠。结果：通过升高灌流液中的K+浓度（从6 ~ 12 mM），低钙猝发的典型放电模式在CA 1区被转化为持续的锋电位活动，突触传递被钙螯合剂EGTA抑制。该活性的特征在于以类似于4 Hz的频率重复的双尖峰，其可持续> 1 h。多单位活动分析表明，升高[K+]（o）和降低[Ca 2 +]（o）均缩短了配对脉冲刺激反应后的抑制期，表明对后超极化（AHP）活动的抑制。结论：这些结果表明，当突触传递被阻断时，持续性癫痫持续状态样锋电位活动可由非突触机制引起。这种活动的独特的双尖峰模式可能是由较高的K+浓度增加典型的低钙非突触爆发活动的频率。
Purpose: It has been shown that a low-calcium high-potassium solution can generate ictal-like epileptiform activity in vitro and in vivo. Moreover, during status epileptiform activity, the concentration of [K+](o) increases, and the concentration of [Ca2+]o decreases in brain tissue. Therefore we tested the hypothesis that long-lasting persistent spike activity, similar to one of the patterns of status epilepticus, could be generated by a high-potassium, low-calcium solution in the hippocampus in vivo.Methods: Artificial cerebrospinal fluid was perfused over the surface of the exposed left dorsal hippocampus of anesthetized rats. A stimulating electrode and a recording probe were placed in the CA1 region.Results: By elevating K+ concentration from 6 to 12 mM in the perfusate solution, the typical firing pattern of low-calcium ictal bursts was transformed into persistent spike activity in the CA1 region with synaptic transmission being suppressed by calcium chelator EGTA. The activity was characterized by double spikes repeated at a frequency similar to 4 Hz that could last for > 1 h. The analysis of multiple unit activity showed that both elevating [K+](o) and lowering [Ca2+](o) decreased the inhibition period after the response of paired-pulse stimulation, indicating a suppression of the after-hyperpolarization (AHP) activity.Conclusions: These results suggest that persistent status epilepticus-like spike activity can be induced by nonsynaptic mechanisms when synaptic transmission is blocked. The unique double-spike pattern of this activity is presumably caused by higher K+ concentration augmenting the frequency of typical low-calcium nonsynaptic burst activity.