Linked Life Data

17055663

Source:http://linkedlifedata.com/resource/pubmed/id/17055663

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-12-12
pubmed:abstractText
We previously showed that prolonged morphine treatment and chronic inflammation both enhanced delta opioid receptor (deltaOR) cell surface density in lumbar spinal cord neurons. Here, we sought to determine whether administration of morphine to rats with chronic inflammation would further increase the bio-availability of deltaOR, and thereby the analgesic properties of the deltaOR agonist deltorphin, over that produced by inflammation alone. We found that chronic inflammation produced by injection of complete Freund's adjuvant (CFA) into the hind paw resulted in a bilateral increase in the binding and internalization of fluorescent deltorphin in neurons of the lumbar spinal cord as did prolonged morphine treatment [Morinville A, Cahill CM, Aibak H, Rymar VV, Pradhan A, Hoffert C, Mennicken F, Stroh T, Sadikot AF, O'Donnell D, Clarke PB, Collier B, Henry JL, Vincent JP, Beaudet A (2004a) Morphine-induced changes in delta opioid receptor trafficking are linked to somatosensory processing in the rat spinal cord. J Neurosci 24:5549-5559]. This effect was accompanied by an increase in the antinociceptive efficacy of intrathecal deltorphin as measured using the tail-flick test. Treatment of CFA-injected rats with morphine decreased the cell surface availability of deltaOR in neurons of the dorsal horn of the lumbar spinal cord as compared with treatment with CFA alone. Behaviorally, it significantly enhanced the antihyperalgesic effects of deltorphin (plantar test; % maximum possible antihyperalgesic effect (MPAHE)=113.5%+/-32.4% versus 26.1%+/-11.6% in rats injected with CFA alone) but strongly reduced the antinociceptive efficacy of the drug (tail-flick test; % maximum possible antinociceptive effect (MPE)=29.6%+/-3.6% versus 66.6%+/-6.3% in rats injected with CFA alone) suggesting that the latter, but not the former, is linked to the deltaOR trafficking events observed neuroanatomically. These results demonstrate that in chronic inflammation, the antihyperalgesic effects of deltaOR agonists may be enhanced by morphine pre-treatment. They also reveal a dichotomy between mechanisms underlying antihyperalgesic and antinociceptive effects of deltaOR agonists.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
144
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
263-74
pubmed:meshHeading
pubmed-meshheading:17055663-Analgesics, pubmed-meshheading:17055663-Analgesics, Opioid, pubmed-meshheading:17055663-Animals, pubmed-meshheading:17055663-Behavior, Animal, pubmed-meshheading:17055663-Chronic Disease, pubmed-meshheading:17055663-Dose-Response Relationship, Drug, pubmed-meshheading:17055663-Enkephalin, Methionine, pubmed-meshheading:17055663-Freund's Adjuvant, pubmed-meshheading:17055663-Hyperalgesia, pubmed-meshheading:17055663-Inflammation, pubmed-meshheading:17055663-Male, pubmed-meshheading:17055663-Morphine, pubmed-meshheading:17055663-Oligopeptides, pubmed-meshheading:17055663-Pain Threshold, pubmed-meshheading:17055663-Rats, pubmed-meshheading:17055663-Rats, Sprague-Dawley, pubmed-meshheading:17055663-Reaction Time, pubmed-meshheading:17055663-Receptors, Cell Surface, pubmed-meshheading:17055663-Receptors, Opioid, delta, pubmed-meshheading:17055663-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:17055663-Spinal Cord, pubmed-meshheading:17055663-Up-Regulation
pubmed:year
2007
pubmed:articleTitle
Morphine priming in rats with chronic inflammation reveals a dichotomy between antihyperalgesic and antinociceptive properties of deltorphin.
pubmed:affiliation
Department of Neurology and Neurosurgery, Montreal Neurological Institute, Room 896, 3801 University Street, McGill University, Montreal, Quebec, Canada H3A 2B4.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't