IONIC BASIS FOR THE ELECTRORESPONSIVENESS AND OSCILLATORY PROPERTIES OF GUINEA-PIG THALAMIC NEURONS INVITRO
IONIC BASIS FOR THE ELECTRORESPONSIVENESS AND OSCILLATORY PROPERTIES OF GUINEA-PIG THALAMIC NEURONS INVITRO
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DOI：
10.1113/jphysiol.1984.sp015154
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发表时间：
1984-01-01
影响因子：
5.5
通讯作者：
LLINAS, R
中科院分区：
文献类型：
--
作者：
JAHNSEN, H;LLINAS, R
用离体豚鼠间脑切片研究了丘脑神经元电反应性的离子需求。在这些神经元的电流-电压关系的分析显示延迟和异常整流。在水浴中用胆碱取代Na+或加入河豚毒素（TTX）可消除快峰电位和平台电位，见随附的论文。用Co~（2+）、Cd~（2+）或Mn~（2+）阻断Ca~（2+）电导或用Mg~（2+）替代Ca~（2+）可消除低阈值峰电位（l.t.s.）。用Ba2+取代并没有显着增加lts的持续时间，这表明在正常条件下，该响应的下降相是由Ca2+电导的失活引起的。后超极化（a.h.p.）随后的快速尖峰的幅度和持续时间显着降低浴应用的Cd~（2+），Co~（2+）或Mn~（2+），表明这种反应的大部分是由Ca~（2+）依赖的K~+电导（gK [Ca]）。在超极化电流脉冲后，膜电位延迟恢复到基线。这种延迟是由瞬时K+电导产生的，因为它可以通过改变K+的驱动力来修改。假设的树突内记录表明高阈值的钙离子尖峰（h.t.s. s）激活gK [Ca]。真是太棒了当用4-氨基吡啶阻断K+传导时，在体细胞水平上也观察到。丘脑神经元的固有生物物理特性允许它们充当中继系统和在2个不同频率（9 - 10和5 - 6 Hz）下充当单细胞振荡器。这些频率与α相一致。和θ。脑电图的节律，在后一种情况下，与帕金森震颤的频率。
The ionic requirements for electroresponsiveness in thalamic neurons were studied using in vitro slice preparations of the guinea pig diencephalon. Analysis of the current-voltage relationship in these neurons revealed delayed and anomalous rectification. Substitution of Na+ with choline in the bath or addition of tetrodotoxin (TTX) abolished the fast spikes and the plateau potentials, described in the accompanying paper. Ca2+ conductance blockage with Co2+, Cd2+ or Mn2+, or replacement of Ca2+ by Mg2+ abolished the low-threshold spikes (l.t.s.). Substitution with Ba2+ did not significantly increase the duration of the l.t.s., suggesting that under normal conditions the falling phase of this response is brought about by inactivation of the Ca2+ conductance. The after-hyperpolarization (a.h.p.) following fast spikes was markedly reduced in amplitude and duration by bath application of Cd2+, Co2+ or Mn2+, indicating that a large component of this response is generated by a Ca2+-dependent K+ conductance (gK[Ca]). Following hyperpolarizing current pulses, the membrane potential showed a delayed return to base line. This delay is produced by a transient K+ conductance as it can be modified by change the drive force for K+. Presumptive intradendritic recording demonstrated high-threshold Ca2+ spikes (h.t.s.s) which activate a gK[Ca]. Such h.t.s.s. were also seen at the somatic level when K+ conductance was blocked with 4-aminopyridine. The intrinsic biophysical properties of thalamic neurons allow them to serve as relay systems and as single cell oscillators at 2 distinct frequencies, 9-10 and 5-6 Hz. These frequencies coincide with the .alpha. and .theta. rhythms of the EEG and, in the latter case, with the frequency of Parkinson''s tremor.