Linked Life Data

10338306

Source:http://linkedlifedata.com/resource/pubmed/id/10338306

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-7-16
pubmed:abstractText
The properties of single motor units from hind limb muscles and the changes in situations of hyperalgesia are not known in detail. We have therefore characterized the properties of single motor units in normal Wistar male rats and in rats with carrageenan-induced inflammation, under alpha-chloralose anaesthesia. Units were studied from three different muscles: peroneus longus, tibialis anterior and extensor digitorum longus. The properties of single motor units were not homogeneous in the three muscles studied in normal animals, showing different sizes of cutaneous receptive fields, thresholds for natural and electrical stimulation, and encoding of responses at different intensities of stimulation. Intraplantar injections of carrageenan induced a significant inflammation of the paw and a change in spontaneous behaviour observed in open field experiments. After inflammation, the responses to cutaneous stimulation of the single motor units became more homogeneous. The threshold for mechanical stimulation was lower for peroneus longus and tibialis anterior but not for extensor digitorum longus units when compared to normal animals. The receptive fields were larger when mapped with a 500 mN von Frey hair but not when mapped using a threshold intensity hair. The threshold for thermal stimulation was lower after inflammation than in normal conditions in all cases, whereas the threshold for electrical stimulation was lower in tibialis anterior and extensor digitorum longus units. An enhancement of responses related to the increase of stimulus intensity was seen in normal animals in all muscles for mechanical and electrical stimuli (but not for thermal). After inflammation, a relationship between firing rate and intensity of stimulation was seen in all cases studied. The firing of single motor units showed over 50% adaptation in the normal condition and over 75% after inflammation when stimulated for 10 s at mechanical threshold intensity. After inflammation, the rate of adaptation was significantly lower when suprathreshold intensity was used for mechanical stimulation. No differences were seen in the adaptation of units to thermal stimulation. We conclude that, in situations of hyperalgesia due to inflammation, the threshold, encoding of stimulus intensity and adaptation of single motor units from different muscles changed, resulting in a narrower range of responses and a more homogeneous population of units.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
90
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1393-402
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Response properties of hind limb single motor units in normal rats and after carrageenan-induced inflammation.
pubmed:affiliation
Departamento de Fisiología, Facultad de Medicina, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't