Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1999-5-3
pubmed:abstractText
1. The effects of impulse activity on conduction in cutaneous C fibres have been examined in 46 microneurographic recordings from 11 normal subjects and 11 diabetic patients with normal nerve conduction. A tungsten microelectrode was inserted into a cutaneous nerve, usually the superficial peroneal close to the ankle, and intraneural microstimulation was used to identify an area of skin innervated. Three minute trains of 0.25 ms stimuli at 1, 2 and 4 Hz were then delivered to the surface of the skin, separated by intervals of 6 min with stimulation at 0.25 Hz. Slowing and block of conduction were measured from the nerve responses for up to seven C units per stimulation sequence. 2. Three types of C unit were distinguished by their responses to repetitive stimulation: type 1 units slowed progressively during the 3 min trains; slowing of type 2 units reached a plateau within 1 min; while type 3 units hardly slowed at all. Data from normal and diabetic subjects did not differ and were pooled. After 3 min at 2 Hz, the percentage increases in latency were for type 1, 28.3 +/- 9.7 (n = 63 units, mean +/- s.d.); for type 2, 5.2 +/- 1.6 (n = 14); and for type 3, 0.8 +/- 0.5 (n = 5), with no overlap. After 3 min at 4 Hz, 58 % of type 1 units (but no type 2 or 3 units) blocked intermittently. Recovery of latency after stimulation was faster for type 2 than for type 1 units, but conduction velocities of the three types were similar. 3. Type 1 units were identified as nociceptors and 7 type 2 units were identified as 'cold' fibres, activated by non-noxious cold, with no overlap in modality. None of the units tested was activated by weak mechanical stimuli or reflex sympathetic activation. 4. Spike waveforms were averaged for 18 type 1, 10 type 2 and 6 type 3 units. All units had predominantly triphasic action potentials with a major negative peak, but those of type 3 units were on average both smaller and briefer than those of type 1 and type 2 units. 5. It is concluded that repetitive electrical stimulation reliably differentiates nociceptive from cold-specific C fibres innervating human hairy skin, as has previously been shown for the rat. Cold fibres can propagate impulses continuously at much higher rates than nociceptive fibres. The nature of the type 3 units is unclear.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-10066892, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-13417134, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-1802341, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-2000105, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-2231398, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-2443652, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-2640470, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-4141858, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-4454990, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-5653884, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-5673644, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-7823139, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-8492149, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-8596662, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-8809788, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-8815797, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-9120582, http://linkedlifedata.com/resource/pubmed/commentcorrection/10066906-9466589
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3751
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
515 ( Pt 3)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
799-811
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Activity-dependent slowing of conduction differentiates functional subtypes of C fibres innervating human skin.
pubmed:affiliation
Neuromuscular Unit, Good Samaritan Hospital & Medical Center, Oregon Health Sciences University, Portland, OR, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't