INFLUENCES OF SINUSOIDAL ELECTRIC-FIELDS ON EXCITABILITY IN THE RAT HIPPOCAMPAL SLICE
INFLUENCES OF SINUSOIDAL ELECTRIC-FIELDS ON EXCITABILITY IN THE RAT HIPPOCAMPAL SLICE
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DOI：
10.1016/0006-8993(84)90293-2
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发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
ADEY, WR
中科院分区：
文献类型：
--
作者：
BAWIN, SM;SHEPPARD, AR;ADEY, WR
在大鼠海马切片中研究了细胞外正弦电场对 CA1 锥体神经元兴奋通路中单个测试脉冲引起的群体尖峰幅度的影响。组织中的场具有脑电图梯度的量级。将代表海马活动的频率 5 Hz 的刺激与点火程序中常用的 60 Hz 进行比较。使用 5 和 60 Hz 场（灌注溶液中 20-70 mV/cmp-p）进行短暂刺激（5-30 秒）通常会产生群体峰值的长期增加（> 10 分钟）。 60 Hz（而非 5 Hz）的场也会引起短期抑制（1-6 分钟）或瞬态后场激励（15-30 秒）。长时间刺激（3 分钟）强调了这种频率依赖性反应：5 Hz 的场会引起持久的增强，而 60 Hz 的场总是导致渐进性抑制，在刺激结束后持续几分钟。这些效应表现为 CA1 神经元的整体反应。在突触传递阻断过程中研究的逆向反应（0.2 mM Ca2+、4 mM Mg2+）在任一频率的 3 分钟场刺激期间和之后均被抑制，这可能反映了组织中失败的 Ca 机制。场对突触或逆向刺激引起的电势的影响与传递测试脉冲的正弦波的相位无关，反对场对细胞膜的直接极化。实验证据表明脑电图样场在海马兴奋性中发挥功能作用。
The influence of extracellular sinusoidal electric fields on the amplitude of population spikes evoked by single test pulses in excitatory pathways to CA1 pyramidal neurons was studied in rat hippocampal slices. The fields in the tissue were of the order of EEG gradients. Stimulation at 5 Hz, a frequency represntative of hippocampal activity, was compared with 60 Hz, which is often used in kindling procedures. Brief stimulation (5-30 s) with both 5 and 60 Hz fields (20-70 mV/cmp-p in the perfusing solution) often produced a long-term increase (> 10 min) of the population spike. Fields at 60 Hz, but not at 5 Hz, also induced short-term depression (1-6 min) or transient post-field excitation (15-30 s). Prolonged stimulation (3 min) emphasized this frequency dependent response: fields at 5 Hz induced long-lasting potentiation while fields at 60 Hz always resulted in progressive depression persisting for a few minutes after the end of stimulation. These effects appeared as a global response of CA1 neurons. Antidromic responses studied during blockade of synaptic transmission (0.2 mM Ca2+, 4 mM Mg2+) were depressed during and following 3 min field stimulation at either frequency, which could reflect failing Ca mechanisms in the tissue. The field influence on the potential evoked by synaptic or antidromic stimulation was independent of the phase of the sine wave at which the test pulse was delivered, arguing against a direct polarization of the cell membrane by the fields. The experimental evidence suggests a functional role for EEG-like fields in hippocampal excitability.