Neuromodulators, not activity, control coordinated expression of ionic currents
Neuromodulators, not activity, control coordinated expression of ionic currents
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DOI：
10.1523/jneurosci.1274-07.2007
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发表时间：
2007-08-08
影响因子：
5.3
通讯作者：
Golowasch, Jorge
中科院分区：
文献类型：
--
作者：
Khorkova, Olga;Golowasch, Jorge
个体之间相同神经元的电活动通常在很长一段时间内非常相似和稳定。然而，决定这些神经元电活动的离子电流在动物之间表现出广泛的振幅变化。单个电流振幅的这种看似随机的可变性可能会模糊全局减少可变性的机制，并有助于产生类似的神经元输出。其中一种机制可能是离子电流表达的协调调节。通过对北方巨蟹幽门神经网络的研究，我们发现对该网络的神经调节输入的去除（去中心化）伴随着离子电流水平协调调节的丧失。此外，去中心化引起了几个离子电流水平的巨大变化。通过持续外源性应用proctolin（一种内源性神经调节肽）到幽门网络，可以防止协调节的丧失和当前水平的变化。这种肽不会对受去中心化影响的任何电流施加快速监管行动。我们得出结论，神经调节输入到幽门神经网络在离子电流表达的调节中具有新的作用。从长期来看，它们可以控制多个电压门控离子电流的协调表达，而这些离子电流不会被剧烈调节。我们的研究结果表明，当前的协同调节限制了神经元的内在可塑性和网络对扰动的响应能力。电导协同调节的丧失可能是促进功能恢复的一种机制。
Electrical activity in identical neurons across individuals is often remarkably similar and stable over long periods. However, the ionic currents that determine the electrical activity of these neurons show wide animal-to-animal amplitude variability. This seemingly random variability of individual current amplitudes may obscure mechanisms that globally reduce variability and that contribute to the generation of similar neuronal output. One such mechanism could be the coordinated regulation of ionic current expression. Studying identified neurons of the Cancer borealis pyloric network, we discovered that the removal of neuromodulatory input to this network (decentralization) was accompanied by the loss of the coordinated regulation of ionic current levels. Additionally, decentralization induced large changes in the levels of several ionic currents. The loss of coregulation and the changes in current levels were prevented by continuous exogenous application of proctolin, an endogenous neuromodulatory peptide, to the pyloric network. This peptide does not exert fast regulatory actions on any of the currents affected by decentralization. We conclude that neuromodulatory inputs to the pyloric network have a novel role in the regulation of ionic current expression. They can control, over the long term, the coordinated expression of multiple voltage-gated ionic currents that they do not acutely modulate. Our results suggest that current coregulation places constraints on neuronal intrinsic plasticity and the ability of a network to respond to perturbations. The loss of conductance coregulation may be a mechanism to facilitate the recovery of function.