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Identification of mechano-sensitive C fibre sensitization and contribution to nerve injury-induced mechanical hyperalgesia.
Eur J Pain. 2016 Apr; 20(4):615-25.EJ

Abstract

BACKGROUND

C fibre hyperexcitability is fundamental to chronic pain development in humans and rodents; therefore, peripheral sensory neuronal sensitization plays a role in the development of mechanical hyperalgesia. However, the axonal properties and underlying mechanisms that are associated to these chronic pain states still require investigation.

METHODS

Teased fibre electrophysiology of the saphenous nerve was used to identify C fibres in naïve and nerve-injured rats. C fibres were identified using electrical stimulation which further provided conduction velocity slowing profiles. From these nerve filaments evoked responses to mechanical stimuli were recorded. Vehicle or galanin were applied directly to the saphenous nerve trunk prior to stimulation.

RESULTS

Increased levels of mechanically evoked activity in mechano-sensitive C fibres was associated to reduced conduction failure, enhanced conduction velocity latency recovery and reduced conduction velocity slowing. Mechanical hyperalgesia developed in nerve-injured animals in which mechano-sensitive C fibres demonstrated increased mechanically evoked responses and reduced rate of adaptation. Mechano-sensitive C fibres in nerve-injured animals had reduced levels of conduction velocity slowing, enhanced rate of conduction velocity recovery and reduced firing frequency failure versus naïve animals; all hallmarks of enhanced sensory neuronal excitability. Directly applying the antinociceptive agent galanin to the saphenous nerve trunk in naive animals led to increased conduction failure, reduced latency recovery rate and increased levels of conduction velocity slowing.

DISCUSSION

Nerve injury-induced enhanced neural responses to mechanical stimulation are associated to defined parameters setout by conduction velocity slowing, mediated via axonal processing. Application of galanin inhibits axonal excitability.

Authors+Show Affiliations

Cancer Biology, School of Medicine, University of Nottingham, Queen's Medical Centre, UK.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26469197

Citation

Hulse, R P.. "Identification of Mechano-sensitive C Fibre Sensitization and Contribution to Nerve Injury-induced Mechanical Hyperalgesia." European Journal of Pain (London, England), vol. 20, no. 4, 2016, pp. 615-25.
Hulse RP. Identification of mechano-sensitive C fibre sensitization and contribution to nerve injury-induced mechanical hyperalgesia. Eur J Pain. 2016;20(4):615-25.
Hulse, R. P. (2016). Identification of mechano-sensitive C fibre sensitization and contribution to nerve injury-induced mechanical hyperalgesia. European Journal of Pain (London, England), 20(4), 615-25. https://doi.org/10.1002/ejp.779
Hulse RP. Identification of Mechano-sensitive C Fibre Sensitization and Contribution to Nerve Injury-induced Mechanical Hyperalgesia. Eur J Pain. 2016;20(4):615-25. PubMed PMID: 26469197.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of mechano-sensitive C fibre sensitization and contribution to nerve injury-induced mechanical hyperalgesia. A1 - Hulse,R P, Y1 - 2015/10/02/ PY - 2015/08/11/accepted PY - 2015/10/16/entrez PY - 2015/10/16/pubmed PY - 2016/12/15/medline SP - 615 EP - 25 JF - European journal of pain (London, England) JO - Eur J Pain VL - 20 IS - 4 N2 - BACKGROUND: C fibre hyperexcitability is fundamental to chronic pain development in humans and rodents; therefore, peripheral sensory neuronal sensitization plays a role in the development of mechanical hyperalgesia. However, the axonal properties and underlying mechanisms that are associated to these chronic pain states still require investigation. METHODS: Teased fibre electrophysiology of the saphenous nerve was used to identify C fibres in naïve and nerve-injured rats. C fibres were identified using electrical stimulation which further provided conduction velocity slowing profiles. From these nerve filaments evoked responses to mechanical stimuli were recorded. Vehicle or galanin were applied directly to the saphenous nerve trunk prior to stimulation. RESULTS: Increased levels of mechanically evoked activity in mechano-sensitive C fibres was associated to reduced conduction failure, enhanced conduction velocity latency recovery and reduced conduction velocity slowing. Mechanical hyperalgesia developed in nerve-injured animals in which mechano-sensitive C fibres demonstrated increased mechanically evoked responses and reduced rate of adaptation. Mechano-sensitive C fibres in nerve-injured animals had reduced levels of conduction velocity slowing, enhanced rate of conduction velocity recovery and reduced firing frequency failure versus naïve animals; all hallmarks of enhanced sensory neuronal excitability. Directly applying the antinociceptive agent galanin to the saphenous nerve trunk in naive animals led to increased conduction failure, reduced latency recovery rate and increased levels of conduction velocity slowing. DISCUSSION: Nerve injury-induced enhanced neural responses to mechanical stimulation are associated to defined parameters setout by conduction velocity slowing, mediated via axonal processing. Application of galanin inhibits axonal excitability. SN - 1532-2149 UR - https://www.unboundmedicine.com/medline/citation/26469197/Identification_of_mechano_sensitive_C_fibre_sensitization_and_contribution_to_nerve_injury_induced_mechanical_hyperalgesia_ L2 - https://doi.org/10.1002/ejp.779 DB - PRIME DP - Unbound Medicine ER -