The long term objective of this project is to determine how activation of mu and delta-opioid receptors leads to distinct intracellular signals. Although mu- and delta-opioid receptors may relay intracellular messages in a similar fashion, a clear distinction in the abuse and dependence producing potential of opioids suggests significant differences are yet to be discovered. For this project, a cellular model has been developed in which cloned mu and delta-opioid receptors in stably transfected GH3 cells interact differently with two intracellular effectors, adenylyl cyclase and Ca++ channels. This unique and important model will be used to identify fundamental differences between mu- and delta-opioid signal transduction cascades. This will be accomplished by the systematic analysis of the interactions between opioid receptors, G proteins and effectors in these unique clones. First, the effect of receptor density on mu- and delta-coupling to effectors will be determined. Second, signal transduction in clones expressing only mu-, only delta, or both mu and delta-opioid receptors will be examined. Third, the association of opioid receptors with G proteins will be determined by purification of agonist-stimulated receptor-G protein complexes. Fourth, the activation of G proteins by opioid receptors will be studied using agonist-induced incorporation of [32P]azidoanilido-GTP into G-alpha subunits. Fifth, the composition of the heterotrimeric G proteins (G-alpha, G-beta- and G-gamma subunits) responsible for coupling mu and delta- receptors to effectors will be confirmed by the use of antisense oligonucleotides targeting specific G protein subunits. Finally, the association of Ca2+ channels with G alpha and/or G-beta,gamma subunits will be assessed after the immunoprecipitation of G protein/Ca2+ channel complexes. Understanding basic differences in the way mu and delta-opioid receptors relay information intracellularly could lead to the development of new methods for the treatment of opioid abuse and pain management.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29DA010936-01A1
Application #
2502171
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Lin, Geraline
Project Start
1998-01-15
Project End
2002-12-31
Budget Start
1998-01-15
Budget End
1998-12-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Arkansas for Medical Sciences
Department
Pharmacology
Type
Schools of Medicine
DUNS #
City
Little Rock
State
AR
Country
United States
Zip Code
72205