Linked Life Data

16139823

Source:http://linkedlifedata.com/resource/pubmed/id/16139823

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2005-10-11
pubmed:abstractText
Male rats are more sensitive than female rats to the antinociceptive action of morphine. The present study used age-matched (9-10 weeks old) male and female Sprague-Dawley rats to investigate whether this difference is due to variation in micro-opioid receptor binding and G protein activation. In the warm-water tail-withdrawal assay at both 50 degrees C and 55 degrees C, morphine was 2-3 times more potent in males than females. In contrast, micro-opioid receptor number and the binding affinity of the micro-opioid agonists morphine and DAMGO in membranes from whole brain, cortex, thalamus, and spinal cord were not different between males and females. Similarly, morphine and DAMGO stimulation of G protein, determined using GTPase and [(35)S]GTPgammaS binding assays, did not show a difference between the sexes. The long-lasting micro-opioid receptor antagonist methocinnamox (0.32 mg/kg), given 24 h prior to morphine, reduced micro-opioid receptor number by approximately 50% in thalamic and spinal cord tissue from female and male rats and reduced the antinociceptive potency of morphine. Pretreatment of male rats with 0.32 mg/kg methocinnamox reduced the antinociceptive potency of morphine to that observed in female rats expressing a full complement of micro-opioid receptors. However, with increasing pretreatment doses of methocinnamox, the maximal antinociceptive effect of morphine was decreased in females but not males. The results suggest that pathways downstream of the micro-opioid receptor and G protein are more efficient in male rats than in female rats such that there is a larger receptor reserve for morphine-mediated antinociception.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1872-6240
pubmed:author
pubmed:issnType
Electronic
pubmed:day
5
pubmed:volume
1058
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
137-47
pubmed:meshHeading
pubmed-meshheading:16139823-Analgesics, Opioid, pubmed-meshheading:16139823-Animals, pubmed-meshheading:16139823-Binding, Competitive, pubmed-meshheading:16139823-Central Nervous System, pubmed-meshheading:16139823-Cinnamates, pubmed-meshheading:16139823-Down-Regulation, pubmed-meshheading:16139823-Drug Interactions, pubmed-meshheading:16139823-Enkephalin, Ala(2)-MePhe(4)-Gly(5)-, pubmed-meshheading:16139823-Female, pubmed-meshheading:16139823-Male, pubmed-meshheading:16139823-Morphine, pubmed-meshheading:16139823-Morphine Derivatives, pubmed-meshheading:16139823-Nociceptors, pubmed-meshheading:16139823-Pain, pubmed-meshheading:16139823-Pain Measurement, pubmed-meshheading:16139823-Rats, pubmed-meshheading:16139823-Rats, Sprague-Dawley, pubmed-meshheading:16139823-Receptors, G-Protein-Coupled, pubmed-meshheading:16139823-Receptors, Opioid, mu, pubmed-meshheading:16139823-Sex Characteristics
pubmed:year
2005
pubmed:articleTitle
Comparison of the antinociceptive effect of acute morphine in female and male Sprague-Dawley rats using the long-lasting mu-antagonist methocinnamox.
pubmed:affiliation
Department of Pharmacology, University of Michigan Medical School, 1301 MSRB III, Ann Arbor, MI 48109, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, N.I.H., Extramural