Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2001-3-6
pubmed:abstractText
Whereas tissue injury increases spinal dynorphin expression, the functional relevance of this upregulation to persistent pain is unknown. Here, mice lacking the prodynorphin gene were studied for sensitivity to non-noxious and noxious stimuli, before and after induction of experimental neuropathic pain. Prodynorphin knock-out (KO) mice had normal responses to acute non-noxious stimuli and a mild increased sensitivity to some noxious stimuli. After spinal nerve ligation (SNL), both wild-type (WT) and KO mice demonstrated decreased thresholds to innocuous mechanical and to noxious thermal stimuli, indicating that dynorphin is not required for initiation of neuropathic pain. However, whereas neuropathic pain was sustained in WT mice, KO mice showed a return to baselines by post-SNL day 10. In WT mice, SNL upregulated lumbar dynorphin content on day 10, but not day 2, after injury. Intrathecal dynorphin antiserum reversed neuropathic pain in WT mice at post-SNL day 10 (when dynorphin was upregulated) but not on post-SNL day 2; intrathecal MK-801 reversed SNL-pain at both times. Opioid (mu, delta, and kappa) receptor density and G-protein activation were not different between WT and KO mice and were unchanged by SNL injury. The observations suggest (1) an early, dynorphin-independent phase of neuropathic pain and a later dynorphin-dependent stage, (2) that upregulated spinal dynorphin is pronociceptive and required for the maintenance of persistent neuropathic pain, and (3) that processes required for the initiation and the maintenance of the neuropathic pain state are distinct. Identification of mechanisms that maintain neuropathic pain appears important for strategies to treat neuropathic pain.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1779-86
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:11222667-Animals, pubmed-meshheading:11222667-Chronic Disease, pubmed-meshheading:11222667-Disease Models, Animal, pubmed-meshheading:11222667-Dizocilpine Maleate, pubmed-meshheading:11222667-Dynorphins, pubmed-meshheading:11222667-Excitatory Amino Acid Antagonists, pubmed-meshheading:11222667-Hyperesthesia, pubmed-meshheading:11222667-Immune Sera, pubmed-meshheading:11222667-Injections, Spinal, pubmed-meshheading:11222667-Ligation, pubmed-meshheading:11222667-Lumbosacral Region, pubmed-meshheading:11222667-Male, pubmed-meshheading:11222667-Mice, pubmed-meshheading:11222667-Mice, Knockout, pubmed-meshheading:11222667-Neuralgia, pubmed-meshheading:11222667-Pain Measurement, pubmed-meshheading:11222667-Pain Threshold, pubmed-meshheading:11222667-Physical Stimulation, pubmed-meshheading:11222667-Reaction Time, pubmed-meshheading:11222667-Receptors, Opioid, pubmed-meshheading:11222667-Spinal Cord, pubmed-meshheading:11222667-Spinal Nerves
pubmed:year
2001
pubmed:articleTitle
Pronociceptive actions of dynorphin maintain chronic neuropathic pain.
pubmed:affiliation
Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.