An important goal towards understanding how opioid drugs interact with their receptors is to discover the relationship between the primary sequence of the opioid receptor proteins and the receptor type-selectivity exhibited by the opioid drugs. The proposed research addresses the programmatic interest of NIDA in the neuroscience of opioids. Opioid receptors come in three types; mu, delta and kappa. Most clinically-used opioid analgesics, as well as abused opioids, mediate their effects by acting at mu opioid receptors (MOR). The proposed project is a competitive continuing application for an AREA grant that seeks to 1) obtain a novel dataset of vertebrate MOR cDNA clones, 2) express and characterize these novel opioid receptors in transfected cell lines, 3) use bioinformatic methods to identify cDNA sequences and individual amino acids that may confer mu opioid selectivity, and 4) validate identified amino acids by creating novel mutant MOR cDNA to characterize in transfected cell cultures.
These aims will be carried be using a PCR-based strategy to obtain novel opioid receptor-like cDNA from mRNA isolated from non-mammalian vertebrate brain tissue, by using state-of- the-art molecular pharmacology methods to transfect CHO cells with novel opioid receptor-like cDNA and characterize their type-selectivity using radioligand binding techniques, by applying methods of comparative bioinformatics analyses of opioid receptor types and individual amino acids, and by using methods to carry-out site-directed mutagenesis on novel MOR proteins. The expected results will provide testable hypotheses of the molecular evolution of vertebrate MOR receptors with regard to mu opioid selectivity correlated to primary amino acid sequence. This information is crucial for a complete understanding of how opioid drugs bind to their target receptors. This will address public health initiatives as the expected results will provide novel insights for the design of new opioid drugs for the clinic and for the treatment of opioid dependence. This project seeks to understand how opioid analgesic drugs, like morphine, are selective for their molecular targets in the brain, called opioid receptor proteins. As all proteins are made up of many amino acids strung together, understanding which amino acids are needed for morphine and other opioid analgesic drugs to bind to them is crucial for the design of better analgesics to treat pain. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
2R15DA012448-05A1
Application #
7252900
Study Section
Molecular Neuropharmacology and Signaling Study Section (MNPS)
Program Officer
Thomas, David A
Project Start
1999-06-01
Project End
2011-03-31
Budget Start
2007-04-01
Budget End
2011-03-31
Support Year
5
Fiscal Year
2007
Total Cost
$206,850
Indirect Cost
Name
Osu Center of Health Sciences
Department
Pharmacology
Type
Schools of Osteopathy
DUNS #
606192896
City
Tulsa
State
OK
Country
United States
Zip Code
74107
Stevens, Craig W (2015) Bioinformatics and evolution of vertebrate nociceptin and opioid receptors. Vitam Horm 97:57-94
Stevens, Craig W (2011) Analgesia in amphibians: preclinical studies and clinical applications. Vet Clin North Am Exot Anim Pract 14:33-44
Mohan, Shekher; Davis, Randall L; DeSilva, Udaya et al. (2010) Dual regulation of mu opioid receptors in SK-N-SH neuroblastoma cells by morphine and interleukin-1ýý: evidence for opioid-immune crosstalk. J Neuroimmunol 227:26-34
Stevens, Craig W (2009) The evolution of vertebrate opioid receptors. Front Biosci (Landmark Ed) 14:1247-69
Stevens, Craig W; Martin, Kristin K; Stahlheber, Brad W (2009) Nociceptin produces antinociception after spinal administration in amphibians. Pharmacol Biochem Behav 91:436-40
Davis, Randall L; Buck, Daniel J; Saffarian, Neda et al. (2008) Beta-funaltrexamine inhibits inducible nitric-oxide synthase expression in human astroglial cells. J Neuroimmune Pharmacol 3:150-3
Brasel, Chris M; Sawyer, Gregory W; Stevens, Craig W (2008) A pharmacological comparison of the cloned frog and human mu opioid receptors reveals differences in opioid affinity and function. Eur J Pharmacol 599:36-43
Stevens, Craig W; Toth, Geza; Borsodi, Anna et al. (2007) Xendorphin B1, a novel opioid-like peptide determined from a Xenopus laevis brain cDNA library, produces opioid antinociception after spinal administration in amphibians. Brain Res Bull 71:628-32
Davis, Randall L; Buck, Daniel J; Saffarian, Neda et al. (2007) The opioid antagonist, beta-funaltrexamine, inhibits chemokine expression in human astroglial cells. J Neuroimmunol 186:141-9
Newman, Leslie C; Sands, Steven S; Wallace, David R et al. (2002) Characterization of mu, kappa, and delta opioid binding in amphibian whole brain tissue homogenates. J Pharmacol Exp Ther 301:364-70

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