Linked Life Data

2352181

Source:http://linkedlifedata.com/resource/pubmed/id/2352181

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1990-7-16
pubmed:abstractText
1. The ventral roots of the spinal cord contain a large number of unmyelinated primary afferent neurones. There is some controversy, however, about the function of these fibres and the route of their central projection. Here we have used electrophysiological techniques to quantify the central projection patterns of these neurones in the segment S2 of adult chloralose-anaesthesized cats. 2. A total of 1185 single unmyelinated units were recorded in small filaments isolated from intact and de-efferented ventral roots or intact dorsal roots of the segment S2 in nineteen cats. The projection patterns of these neurones were tested using supramaximal electrical stimulation of the pelvic and pudendal nerve (the main tributaries of the spinal nerve of this segment) and of the segmental companion root (dorsal or ventral as appropriate). 3. The principal finding of this study is that 85% of unmyelinated afferent axons in the ventral root are direct and exclusive projections. They constitute a separate class of afferents which is only capable of transmitting information from the periphery via the ventral roots. However, the proportion of these fibres that enter the central nervous system is unknown and it seems likely that some of them peter out as they approach the spinal cord and end blindly. The functional role of such afferents remains obscure. 4. For the remaining 15% of unmyelinated ventral root afferents, a projection into the segmental dorsal root was found. The majority of those fibres (about two-thirds) are primary afferent neurones innervating the pia mater. Some of these units had a small spot-like receptive field and responded to mechanical stimuli such as pressure and stretch of the root. They did not have axon projections in a peripheral nerve. 5. A few (5%) unmyelinated ventral root fibres are collateral branches of normal primary afferents projecting through the dorsal root. These trifurcating neurones are a small population which make up only some 0.5% of all dorsal root ganglion cells. The functional significance of this population too is unknown. 6. For none of the fibres that projected into both dorsal and ventral root was there positive evidence for the existence of looping axons that merely make a detour into one of the roots. Although the existence of loops cannot completely be excluded, our evidence suggests that they can constitute at most 5% of the unmyelinated ventral root afferents.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-1271293, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-2418069, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-2426310, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-2472190, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-268137, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3030500, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3241660, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3529051, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3559992, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3587740, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3651817, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3683978, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3722468, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3907749, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3950079, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-3958979, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-4031987, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-4056096, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-4817345, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6172582, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6181850, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6194478, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6202726, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-641227, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6725638, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6839150, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-6994143, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-7175548, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-7276255, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-7276258, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-7430430, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-838891, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-861724, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-944774, http://linkedlifedata.com/resource/pubmed/commentcorrection/2352181-957227
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3751
pubmed:author
pubmed:issnType
Print
pubmed:volume
422
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
265-87
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
A quantitative study of the central projection patterns of unmyelinated ventral root afferents in the cat.
pubmed:affiliation
Physiologisches Institut, Christian-Albrechts-Universität zu Kiel, FRG.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't