title: Essential role of axonal VGSC inactivation in time-dependent deceleration and unreliability of spike propagation at cerebellar Purkinje cells.
abstract: BACKGROUND
  The output of the neuronal digital spikes is fulfilled by axonal propagation and synaptic transmission to influence postsynaptic cells. Similar to synaptic transmission, spike propagation on the axon is not secure, especially in cerebellar Purkinje cells whose spiking rate is high. The characteristics, mechanisms and physiological impacts of propagation deceleration and infidelity remain elusive. The spike propagation is presumably initiated by local currents that raise membrane potential to the threshold of activating voltage-gated sodium channels (VGSC).
  
  
  RESULTS
  We have investigated the natures of spike propagation and the role of VGSCs in this process by recording spikes simultaneously on the somata and axonal terminals of Purkinje cells in cerebellar slices. The velocity and fidelity of spike propagation decreased during long-lasting spikes, to which the velocity change was more sensitive than fidelity change. These time-dependent deceleration and infidelity of spike propagation were improved by facilitating axonal VGSC reactivation, and worsen by intensifying VGSC inactivation.
  
  
  CONCLUSIONS
  Our studies indicate that the functional status of axonal VGSCs is essential to influencing the velocity and fidelity of spike propagation.
authors.forename: Zhilai
authors.initials: Z
authors.lastname: Yang
authors.forename: Erwei
authors.initials: E
authors.lastname: Gu
authors.forename: Xianfu
authors.initials: X
authors.lastname: Lu
authors.affiliation: Institute of Biophysics, State Key lab for Brain and Cognitive Sciences, Chinese Academy of Sciences, Beijing 100101, China. jhw@sun5.ibp.ac.cn.
authors.forename: Jin-Hui
authors.initials: JH
authors.lastname: Wang
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D002531:Cerebellum / Q000166:cytology*; D003064:Cnidarian Venoms / Q000633:toxicity; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D061566:Voltage-Gated Sodium Channels / Q000378:metabolism*
chemical_list: D003064:Cnidarian Venoms; D061566:Voltage-Gated Sodium Channels