Money Tomas G A, Sproule Michael K J, Hamour Amr F, Robertson R Meldrum
Department of Biology, Queen's University, Kingston, Ontario, Canada.
PLoS One. 2014 Feb 12;9(2):e88570. doi: 10.1371/journal.pone.0088570. eCollection 2014.
Nervous systems are energetically expensive to operate and maintain. Both synaptic and action potential signalling require a significant investment to maintain ion homeostasis. We have investigated the tuning of neural performance following a brief period of anoxia in a well-characterized visual pathway in the locust, the LGMD/DCMD looming motion-sensitive circuit. We hypothesised that the energetic cost of signalling can be dynamically modified by cellular mechanisms in response to metabolic stress. We examined whether recovery from anoxia resulted in a decrease in excitability of the electrophysiological properties in the DCMD neuron. We further examined the effect of these modifications on behavioural output. We show that recovery from anoxia affects metabolic rate, flight steering behaviour, and action potential properties. The effects of anoxia on action potentials can be mimicked by activation of the AMPK metabolic pathway. We suggest this is evidence of a coordinated cellular mechanism to reduce neural energetic demand following an anoxic stress. Together, this represents a dynamically-regulated means to link the energetic demands of neural signaling with the environmental constraints faced by the whole animal.
神经系统的运行和维持需要消耗大量能量。突触信号和动作电位信号都需要大量投入来维持离子稳态。我们研究了在蝗虫一个特征明确的视觉通路——LGMD/DCMD逼近运动敏感电路中，短暂缺氧后神经性能的调整情况。我们假设，信号传递的能量成本可以通过细胞机制动态调整，以应对代谢应激。我们研究了缺氧恢复后是否会导致DCMD神经元电生理特性的兴奋性降低。我们进一步研究了这些改变对行为输出的影响。我们发现，缺氧恢复会影响代谢率、飞行转向行为和动作电位特性。激活AMPK代谢途径可以模拟缺氧对动作电位的影响。我们认为，这证明了存在一种协调的细胞机制，可在缺氧应激后降低神经能量需求。总之，这代表了一种动态调节的方式，将神经信号的能量需求与整个动物面临的环境限制联系起来。
