State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing, 100871, China.
College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing, 100871, China.
Neurosci Bull. 2022 Nov;38(11):1330-1346. doi: 10.1007/s12264-022-00931-9. Epub 2022 Aug 19.
The back-propagating action potential (bpAP) is crucial for neuronal signal integration and synaptic plasticity in dendritic trees. Its properties (velocity and amplitude) can be affected by dendritic morphology. Due to limited spatial resolution, it has been difficult to explore the specific propagation process of bpAPs along dendrites and examine the influence of dendritic morphology, such as the dendrite diameter and branching pattern, using patch-clamp recording. By taking advantage of Optopatch, an all-optical electrophysiological method, we made detailed recordings of the real-time propagation of bpAPs in dendritic trees. We found that the velocity of bpAPs was not uniform in a single dendrite, and the bpAP velocity differed among distinct dendrites of the same neuron. The velocity of a bpAP was positively correlated with the diameter of the dendrite on which it propagated. In addition, when bpAPs passed through a dendritic branch point, their velocity decreased significantly. Similar to velocity, the amplitude of bpAPs was also positively correlated with dendritic diameter, and the attenuation patterns of bpAPs differed among different dendrites. Simulation results from neuron models with different dendritic morphology corresponded well with the experimental results. These findings indicate that the dendritic diameter and branching pattern significantly influence the properties of bpAPs. The diversity among the bpAPs recorded in different neurons was mainly due to differences in dendritic morphology. These results may inspire the construction of neuronal models to predict the propagation of bpAPs in dendrites with enormous variation in morphology, to further illuminate the role of bpAPs in neuronal communication.
逆行传播动作电位（bpAP）对树突中的神经元信号整合和突触可塑性至关重要。其特性（速度和幅度）可受树突形态影响。由于空间分辨率有限，使用膜片钳记录技术很难探索 bpAP 在树突中沿特定路径的具体传播过程，并研究树突形态（如树突直径和分支模式）对其的影响。利用全光学电生理方法 Optopatch，我们对树突中 bpAP 的实时传播进行了详细记录。结果发现，在单个树突中，bpAP 的速度并不均匀，并且同一神经元的不同树突中 bpAP 的速度也不同。bpAP 的速度与传播其上的树突直径呈正相关。此外，当 bpAP 通过树突分支点时，其速度会显著降低。与速度相似，bpAP 的幅度也与树突直径呈正相关，并且不同树突的 bpAP 衰减模式也不同。具有不同树突形态的神经元模型的仿真结果与实验结果非常吻合。这些发现表明，树突直径和分支模式显著影响 bpAP 的特性。不同神经元记录的 bpAP 之间的多样性主要归因于树突形态的差异。这些结果可能启发构建神经元模型来预测具有巨大形态变化的树突中 bpAP 的传播，从而进一步阐明 bpAP 在神经元通讯中的作用。
