Document Detail

Conduction failures in rabbit saphenous nerve unmyelinated fibers.
MedLine Citation:
PMID:  19295243     Owner:  NLM     Status:  MEDLINE    
Recent experimental and theoretical data indicate that the functional capabilities of axons with specialized structures are much more diverse than traditionally thought. However, few observations were concerned with the main axons without arborization. In the present study, electrical stimulation of the saphenous nerve at different frequencies (2, 5, 10, 20 Hz) was used to test the role of activity-dependent effects on the pattern of action potentials that propagate along individual unmyelinated fibers (C fibers) within the trunk of the saphenous nerve in rabbits. Three basic types of C fiber responses to repetitive stimulation were observed: type-1 fibers showed an entrained response without conduction failure; type-2 fibers discharged with intermittent conduction failures; while only sporadic conduction failures happened in type 3. The failure modality in type-2 and type-3 fibers is closely related to the conductive distance as well as the frequency and duration of stimuli which lead to a critical level of conduction velocity slowing. A novel fluctuation in interspike intervals was always observed immediately before the occurrence of the failures, implying that the fluctuation of conduction velocity is correlated with imminent failures. Both the 4-aminopyridine-sensitive potassium current and hyperpolarization-activated cation current were recognized to be involved in the regulation of conduction failure patterns. The results confirmed, at least in part, the existence of conduction failures in the main axon of C fibers, suggesting that axonal operations may also be determinants for adaptation phenomenon and information processing in peripheral nervous system.
Zhi-Ru Zhu; Xiao-Wei Tang; Wen-Ting Wang; Wei Ren; Jun-Ling Xing; Jun-Ran Zhang; Jian-Hong Duan; Yu-Ying Wang; Xiying Jiao; San-Jue Hu
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-03-19
Journal Detail:
Title:  Neuro-Signals     Volume:  17     ISSN:  1424-8638     ISO Abbreviation:  Neurosignals     Publication Date:  2009  
Date Detail:
Created Date:  2009-08-17     Completed Date:  2009-11-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101134359     Medline TA:  Neurosignals     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  181-95     Citation Subset:  IM    
Copyright Information:
Copyright 2009 S. Karger AG, Basel.
Department of Biomedical Engineeringe, Zhejiang University, Hangzhou, China.
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MeSH Terms
4-Aminopyridine / pharmacology
Action Potentials / drug effects,  physiology*
Axons / drug effects,  physiology*,  ultrastructure
Cell Membrane / drug effects,  physiology
Dose-Response Relationship, Drug
Electric Stimulation
Femoral Nerve / cytology,  physiology*
Ion Channel Gating / drug effects,  physiology
Nerve Fibers, Unmyelinated / drug effects,  physiology*,  ultrastructure
Neural Conduction / drug effects,  physiology*
Peripheral Nervous System / cytology,  physiology*
Potassium Channel Blockers / pharmacology
Potassium Channels / drug effects,  physiology
Reaction Time / drug effects,  physiology
Time Factors
Reg. No./Substance:
0/Potassium Channel Blockers; 0/Potassium Channels; 504-24-5/4-Aminopyridine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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