Linked Life Data

12422367

Source:http://linkedlifedata.com/resource/pubmed/id/12422367

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-11-7
pubmed:abstractText
Chronic morphine treatment results in functional uncoupling of the mu opioid receptor and its G protein in both cell culture and animal models. In the present study, Chinese hamster ovary (CHO) cells stably expressing the cloned human mu opioid receptor (hMOR-CHO cells) were incubated with 1 microM of morphine (or no drug) for 20 h. Subsequently, we assessed DAMGO- and morphine-stimulated [(35)S]-GTP-gamma-S binding and agonist-mediated inhibition of forskolin-stimulated cAMP accumulation. Using a single concentration of [(35)S]-GTP-gamma-S (0.05 nM), chronic morphine treatment did not significantly change basal [(35)S]-GTP-gamma-S binding, shifted the morphine EC(50) from 59 nM to 146 nM, and decreased the maximal stimulation (E(max)) from 201% to 177%. Similar results were observed with DAMGO. Binding surface analysis resolved two [(35)S]-GTP-gamma-S binding sites (high-affinity and low-affinity sites). In control cells, morphine stimulated [(35)S]-GTP-gamma-S binding by increasing the B(max) of the high-affinity site. In morphine-treated cells, morphine stimulated [(35)S]-GTP-gamma-S binding by decreasing the high-affinity K(d) without changing the B(max). Morphine treatment increased the EC(50) (5-11-fold) for agonist-mediated inhibition of forskolin-stimulated cAMP accumulation. These changes were not observed in cells expressing a mutant mu opioid receptor which does not develop morphine tolerance, suggesting that the changes in [(35)S]-GTP-gamma-S binding observed in hMOR-CHO cells result from the development of morphine tolerance.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0887-4476
pubmed:author
pubmed:issnType
Print
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Opioid peptide receptor studies. 16. Chronic morphine alters G-protein function in cells expressing the cloned mu opioid receptor.
pubmed:affiliation
Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA.
pubmed:publicationType
Journal Article