2002/03/01 by Sally N. Lawson, S. N. Lawson
Medicine · #Botulinum Toxin and Related Neurological Disorders #Musculoskeletal pain and rehabilitation #Pain Mechanisms and Treatments
paper · pdf · doi:10.1113/eph8702350
openalex publication_date 2002/03/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Nociceptive dorsal root ganglion (DRG) neurones have fibres that conduct in the C, Adelta and Aalpha/beta conduction velocity range. The properties of nociceptive compared with non-nociceptive somatic afferent dorsal root ganglion neurones appear to fall into two patterns, A and B. Pattern A properties of nociceptive neurones, the more common type, include longer action potential duration and slower maximum rate of fibre firing, as well as a greater expression of substance P and calcitonin gene-related peptide immunoreactivity. The values of pattern A properties appear to be graded according to the conduction velocity group (C, Adelta or Aalpha/beta) of the fibres. The most pronounced forms of A-type properties are expressed by nociceptive neurones with C-fibres, and these become less pronounced in nociceptive neurones with Adelta-fibres and least pronounced in those with Aalpha/beta fibres (C > Adelta > Aalpha/beta). Some of these properties are also expressed in a less extreme but similarly graded manner through C, Adelta and Aalpha/beta groups of non-nociceptive low threshold mechanoreceptive (LTM) neurone. The less common pattern B properties of nociceptive neurones have similar values in C-, Adelta- and Aalpha/beta-fibre nociceptive neurones but these clearly differ from LTM units with C-, Adelta- and Aalpha/beta-fibre conduction velocities. These features of nociceptive neurones include consistently larger action potential overshoots and longer after-hyperpolarisation durations in nociceptive than in LTM neurones.