The exact metabolic cost for a single action potential and in particular in the context of ongoing electrical activity were unclear, but new research has now shown that the costs are high and in addition highly specific for different neuronal compartments.
High and variable costs of an action potential.
Our brain uses up to twenty percent of all calories we consume. It has long been suspected that the most important reason for this high energy consumption is the metabolic cost of action potential firing. The exact metabolic cost for a single action potential and in particular in the context of ongoing electrical activity were unclear, but new research has now shown that the costs are high and in addition highly specific for different neuronal compartments.
In a collaboration led by Maarten Kole (NIN-KNAW), the researchers Stefan Hallermann (ENI – Göttingen), Greg Stuart (ANU – Australia) and Christiaan de Kock (CNCR, VU) determined the energy required for action potential spiking in different parts of a single neuron from rat cortex. This allowed a compartment-specific quantification of exactly how many Na+ and K+ ions move across the cell membrane during an action potential. Since these ions always have to be transported back to their original location by an energy-dependent process, a direct insight could be obtained into the energy metabolism of cortical neurons. Based on these new data the researchers then developed a computer model which showed that the total cost of generating and conducting action potentials is high and costs decrease only modestly during high frequency electrical activity.
More information can be found in “State and location dependence of action potential metabolic cost in cortical pyramidal neurons”, Hallerman et al, published in the journal Nature Neuroscience (10.1038/nn.3132).
http://www.nature.com/neuro/journal/vaop/ncurrent/full/nn.3132.html