Saltatory Conduction as an Electrostatic Compressional Wave in the Axoplasm.

In this report, I propose a new model of saltatory conduction by focusing on the behavior of electric charges in the axoplasm, not limited to the membrane. In myelinated nerves, because of the large internodal length and the low ion channel density in the internodal segment, the whole cross-section of the internodal axoplasm would contribute to the signal conduction. Because the conducted signals originate from the sodium ion influx through the voltage-gated sodium (NaV) channel at the Ranvier's nodes, an individual conducted signal can be described as a single electrostatic compressional wave of positive charges in the internodal axoplasm. Based on this model, the total number of NaV channels in one Ranvier's node would regulate the strength of the wave. Also, the internodal length would be important for the faster conduction in larger myelinated axons. Based on the linear relationships between axonal diameter, internodal length, and conduction velocity, the internodal length would be inversely proportional to the ratio of the transmitted overall wave strength at a Ranvier's node to the original strength at the proximal adjacent node. This new mathematical model may have wide applicability and usability for the conduction in myelinated nerves. PMID: 29467340 [PubMed - in process]
Source: The Tohoku Journal of Experimental Medicine - Category: Research Authors: Tags: Tohoku J Exp Med Source Type: research
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