中国神经再生研究(英文版) ›› 2024, Vol. 19 ›› Issue (8): 1631-1632.doi: 10.4103/1673-5374.389636

• 观点:神经损伤修复保护与再生 • 上一篇    下一篇

电压门控离子通道的聚集是髓鞘形成的进化触发因素

  

  • 出版日期:2024-08-15 发布日期:2024-01-03

Clustering of voltage-gated ion channels as an evolutionary trigger of myelin formation

Henrike Ohm, Simone Rey, Christian Klämbt*#br#   

  1. Institut für Neuro- und Verhaltensbiologie, Münster, Germany
  • Online:2024-08-15 Published:2024-01-03
  • Contact: Dr. Christian Klämbt, klaembt@uni-muenster.de.
  • Supported by:
    This work was supported by the Deutsche Forschungsgemeinschaft through funds to CK (SFB 1348, B5, Kl 588/29). 

摘要: https://orcid.org/0000-0002-6349-5800 (Christian Klämbt)

Abstract: Neurons carry apical dendrites that perceive information and a basal axon that transmits the computed information towards its targets. The axon originates at the axon hillock which is followed by the axon initial segment. Here, action potentials are initiated that are based on millisecond long openings of specific voltage-gated sodium and potassium channels that are conserved in all parahoxozoa (Placozoa, Cnidaria, Bilateria) (Li et al., 2015). This indicates that the basic principles in action potential generation and spreading are evolutionarily conserved. The conductance velocity of action potentials likely affects the evolutionary success of any animal species as it contributes, for example, to the success of escape responses. Physical laws state that axonal transduction velocity depends on the size of the axon. Alternatively, conductance speed is gained by arranging voltage-gated ion channels in spatially separated clusters. Such a distribution is thought to be a defining feature of the vertebrate nervous system and accumulations of voltage-gated ion channels are seen at the axon initial segment and the nodes of Ranvier. Together with intervening myelin, this enables saltatory transduction, which allows very fast conduction velocities. Surprisingly, recent work demonstrated a clustered distribution of voltage-gated ion channels in the nervous system of the invertebrate Drosophila melanogaster (Rey et al., 2023). Channels are enriched at the axon initial segments of motor- and sensory neurons, cluster on a molecular scale with spacing of about 0.7 µm, supporting micro-saltatory conductance. Similar to in vertebrates, the positioning of ion channels is influenced by glia. Moreover, glia in adult flies form myelin-like structures next to the axon initial segments (Rey et al., 2023). Thus, the evolution of saltatory conductance is not specific to vertebrates but likely started before the separation of vertebrates and invertebrates.