Dendritic signals from rat hippocampal CA1 pyramidal neurons during coincident pre- and post-synaptic activity: a combined voltage- and calcium-imaging study
Dendritic signals from rat hippocampal CA1 pyramidal neurons during coincident pre- and post-synaptic activity: a combined voltage- and calcium-imaging study
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DOI：
10.1113/jphysiol.2006.125005
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发表时间：
2007-04-15
影响因子：
5.5
通讯作者：
Zecevic, Dejan
中科院分区：
文献类型：
--
作者：
Canepari, Marco;Djurisic, Maja;Zecevic, Dejan
树突膜电位信号的非线性和空间不均匀相互作用代表了诱导活动依赖性长期突触可塑性的第一步，但尚未完全了解，特别是在电极测量范围之外的树突区域。我们结合了海马 CA1 锥体神经元的电压敏感染料记录和 Ca2+ 成像来研究树突乔木的大区域，包括小直径的分支（远端顶端和倾斜树突）。以高空间分辨率监测树突膜电位瞬变，并与重复模式刺激方案的一个周期内的超线性 [Ca2+](i) 变化相关，通常会导致长时程增强 (LTP) 的诱导。虽然在一致的突触前和突触后活动期间峰值膜去极化的增加是诱导超线性 [Ca2+](i) 信号所必需的，这对于 LTP 是必需的，但反向传播树突动作电位 (bAP) 的基线到峰值幅度的变化在此过程中并不重要。在不同的树突位置，在 EPSP-AP 配对引起 [Ca2+](i) 瞬变超线性求和的位点，bAP 的基线到峰值幅度可能会增加、减少或不变。我们建议局部 EPSP 对 bAP 基线到峰值幅度的调节作为一种机制，使膜电位进入通过 NMDA 受体的 Ca2+ 流入的最佳范围（0 至 -15 mV）；这可能需要增强或减小 bAP，具体取决于两个信号的初始大小。
The non-linear and spatially inhomogeneous interactions of dendritic membrane potential signals that represent the first step in the induction of activity-dependent long-term synaptic plasticity are not fully understood, particularly in dendritic regions which are beyond the reach of electrode measurements. We combined voltage-sensitive-dye recordings and Ca2+ imaging of hippocampal CA1 pyramidal neurons to study large regions of the dendritic arbor, including branches of small diameter (distal apical and oblique dendrites). Dendritic membrane potential transients were monitored at high spatial resolution and correlated with supra-linear [Ca2+](i) changes during one cycle of a repetitive patterned stimulation protocol that typically results in the induction of long-term potentiation (LTP). While the increase in the peak membrane depolarization during coincident pre- and post-synaptic activity was required for the induction of supra-linear [Ca2+](i) signals shown to be necessary for LTP, the change in the baseline-to-peak amplitude of the backpropagating dendritic action potential (bAP) was not critical in this process. At different dendritic locations, the baseline-to-peak amplitude of the bAP could be either increased, decreased or unaltered at sites where EPSP-AP pairing evoked supra-linear summation of [Ca2+](i) transients. We suggest that modulations in the bAP baseline-to-peak amplitude by local EPSPs act as a mechanism that brings the membrane potential into the optimal range for Ca2+ influx through NMDA receptors (0 to -15 mV); this may require either boosting or the reduction of the bAP, depending on the initial size of both signals.