Temperature-robust activity patterns arise from coordinated axonal Sodium channel properties
Temperature-robust activity patterns arise from coordinated axonal Sodium channel properties
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DOI：
10.1371/journal.pcbi.1008057
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发表时间：
2020-07-01
影响因子：
4.3
通讯作者：
Stein, Wolfgang
中科院分区：
文献类型：
--
作者：
DeMaegd, Margaret L.;Stein, Wolfgang
动作电位是神经元通信的关键组成部分，它们的精确计时对于学习，记忆和复杂行为等过程至关重要。动作电位通过长轴突传播到它们的突触后伙伴，这要求轴突不仅要忠实地将动作电位传递到远处的突触区域，还要保持它们的时间。当轴突的形态和生理特性不同时，这是特别具有挑战性的，因为预测当外部条件改变时，这些轴突之间的时间会发生分歧。目前还不清楚在动物和人类遇到的温度变化期间，不同的轴突是否以及如何保持定时。我们研究了环境温度的变化是否会导致中枢产生温度鲁棒性活动的神经元外围的不同时间。在结合建模，成像和电生理学的方法中，我们探索了支持定时的机制，通过暴露来自相同甲壳动物（北方癌症）运动回路的三种不同神经元类型的轴突，并参与相同的功能任务到一系列生理温度。我们发现，尽管轴突之间存在很大差异，温度对动作电位传播的影响是温和的，并支持长距离的温度鲁棒定时。我们的建模表明，为了保持定时，这些轴突的潜在通道特性不需要是温度不敏感或高度限制的，但需要协调钠激活门时间常数和最大钠电导的温度敏感性。因此，即使是高度温度敏感的离子通道特性也可以支持不同神经元类型之间和长距离之间的温度鲁棒定时。
Action potentials are a key component of neuronal communication and their precise timing is critical for processes like learning, memory, and complex behaviors. Action potentials propagate through long axons to their postsynaptic partners, which requires axons not only to faithfully transfer action potentials to distant synaptic regions but also to maintain their timing. This is particularly challenging when axons differ in their morphological and physiological properties, as timing is predicted to diverge between these axons when extrinsic conditions change. It is unknown if and how diverse axons maintain timing during temperature changes that animals and humans encounter. We studied whether ambient temperature changes cause different timing in the periphery of neurons that centrally produce temperature-robust activity. In an approach combining modeling, imaging, and electrophysiology, we explored mechanisms that support timing by exposing the axons of three different neuron types from the same crustacean (Cancer borealis) motor circuit and involved in the same functional task to a range of physiological temperatures. We show that despite substantial differences between axons, the effects of temperature on action potential propagation were moderate and supported temperature-robust timing over long-distances. Our modeling demonstrates that to maintain timing, the underlying channel properties of these axons do not need to be temperature-insensitive or highly restricted, but coordinating the temperature sensitivities of the Sodium activation gate time constant and the maximum Sodium conductance is required. Thus, even highly temperature-sensitive ion channel properties can support temperature-robust timing between distinct neuronal types and across long distances.