Endogenous opioid systems play critical roles in analgesia and drug addiction but numerous questions concerning opioid receptor function remain. In this project, we will utilize mice harboring targeted mutations in the DOR1 and MOR1 opioid receptor genes to investigate receptor function in analgesia, development and immune function. We will complement these studies with developmental and genetic analysis of the ORL-1 and orphaninFQ (OFQ) loci that likely interact with classical opioid systems. We will first investigate the pharmacological and behavioral consequences of MOR1 and DOR1 alteration. We will perform receptor binding studies to determine whether the mutations are complete nulls, whether residual binding to morphine, morphine6B-glucuronide (M6G) and receptor subtype-specific ligands can be detected in either mutant. Analgesic assays will be used to determine whether morphine and/or M6G analgesia are absent from the mutant lines, whether pharmacologically-defined subtypes of mu, and delta receptors are coordinately lost, and whether the opioid component of stress-induced analgesia is mediated through MOR1 or DOR1. Confocal microscopy and image analysis will be used to test the hypothesis that receptor alteration leads to abnormalities in neural cell number and morphology at specific sites of normal receptor expression. We will next determine whether a potentially opioid-mediated chemotactic response of macrophages that follows injury to the developing brain is altered in either or both mutants. The expression patterns and levels of non-mutated opioid receptor and opioid peptide genes will be compared in mutant and wild-type mice to establish whether compensation occurs at the transcriptional level. We will then use GTPgS to visualize receptor activation in histological sections and thereby determine when functional receptor coupling begins during development and whether any changes in opioid receptor mRNA in specific mutants extends to the functional level. Finally, we will complete ontogenetic studies of ORL-1 and OFQ expression and then genetically ablate both ORL-1 and OFQ to determine if the early expression of these genes we observe in the nervous system is critical for neuronal differentiation. The phenotypes of these mutants will be compared to evaluate possible functional roles for putative peptides encoded by the OFQ precursor. If viable, these mutants will be tested to resolve conflicting views of OFQ and ORL-1 action in analgesia. Taken together, these studies should resolve multiple uncertanties concerning opioid receptor function in several systems and provide new animal models to investigate analgesia, tolerance, and withdrawal.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA009040-06
Application #
2897926
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Colvis, Christine
Project Start
1994-09-01
Project End
2002-06-30
Budget Start
1999-08-01
Budget End
2000-06-30
Support Year
6
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Neurosciences
Type
Schools of Medicine
DUNS #
622146454
City
Piscataway
State
NJ
Country
United States
Zip Code
08854
Wen, Ting; Peng, Bonnie; Pintar, John E (2009) The MOR-1 opioid receptor regulates glucose homeostasis by modulating insulin secretion. Mol Endocrinol 23:671-8
Wen, Ting; Ansonoff, Michael A; Pintar, John E (2009) The tail pigmentation pattern of C57BL/6J mice affects nociception/pain quantification in the tail flick test. Eur J Pain 13:564-7
Milo, Steven; Ansonoff, Michael; King, Michael et al. (2006) Codeine and 6-acetylcodeine analgesia in mice. Cell Mol Neurobiol 26:1011-9
Ansonoff, Michael A; Zhang, Jiwen; Czyzyk, Traci et al. (2006) Antinociceptive and hypothermic effects of Salvinorin A are abolished in a novel strain of kappa-opioid receptor-1 knockout mice. J Pharmacol Exp Ther 318:641-8
Mathon, Daniel S; Ramakers, Geert M J; Pintar, John E et al. (2005) Decreased firing frequency of midbrain dopamine neurons in mice lacking mu opioid receptors. Eur J Neurosci 21:2883-6
Chefer, Vladimir I; Czyzyk, Traci; Bolan, Elizabeth A et al. (2005) Endogenous kappa-opioid receptor systems regulate mesoaccumbal dopamine dynamics and vulnerability to cocaine. J Neurosci 25:5029-37
Cox, Veronica; Clarke, Sian; Czyzyk, Tracy et al. (2005) Autoradiography in opioid triple knockout mice reveals opioid and opioid receptor like binding of naloxone benzoylhydrazone. Neuropharmacology 48:228-35
McCarthy, Lois E; Nitsche, Joshua F; Pintar, John E et al. (2004) The delta-opioid receptor participates in T-cell development by promoting negative selection. J Neuroimmunol 153:91-8
McLaughlin, Jay P; Myers, Lisa C; Zarek, Paul E et al. (2004) Prolonged kappa opioid receptor phosphorylation mediated by G-protein receptor kinase underlies sustained analgesic tolerance. J Biol Chem 279:1810-8
Hummel, M; Ansonoff, M A; Pintar, J E et al. (2004) Genetic and pharmacological manipulation of mu opioid receptors in mice reveals a differential effect on behavioral sensitization to cocaine. Neuroscience 125:211-20

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