Disease relevance of OPRM1

• 6beta-Naltrexol was also less potent than naltrexone in antagonizing other MOR-mediated effects including respiratory depression and itch/scratching [1].
• The mu-opioid receptor was closely associated with the somatic plasmalemma of the dorsal root ganglion neurons [2].

High impact information on OPRM1

• The data support the use of nonhuman primates to investigate mu-opioid receptor genotype/phenotype relations of relevance to humans [3].
• We investigated the existence of variations in the nonhuman primate mu-opioid receptor gene to determine whether nonhuman primates can model genotype/phenotype associations of relevance to humans [3].
• Similar to the A118G single nucleotide polymorphism (SNP) in the human mu-opioid receptor gene, a SNP discovered in the rhesus monkey mu-opioid receptor gene (C77G) alters an amino acid in the N-terminal arm of the receptor (arginine for proline at position 26) [3].
• The findings suggest that mu-opioid receptor haplotypes in monkeys can contribute to individual variability in stress response and related aggression [3].
• In vitro assays revealed that naltrexone displayed 2-fold higher affinity and potency than 6beta-naltrexol for the MOR binding site and for MOR agonist-stimulated [(35)S]GTPgammaS binding, respectively [1].

Biological context of OPRM1

• A mu-opioid receptor single nucleotide polymorphism in rhesus monkey: association with stress response and aggression [3].
• Using ethylketocyclazocine (EKC) discrimination and diuresis assays in rhesus monkeys (Macaca mulatta), the purpose of the current investigation was to characterize the in vivo kappa-opioid activity of these compounds through the use of an insurmountable mu-opioid receptor antagonist, clocinnamox [4].
• Mu opioid receptor gene expression in immune cells [5].
• Our data would indicate that prolonged gestational cocaine exposure causes mu-opioid receptor mRNA down-regulation in specific brain regions of the fetus [6].
• Ribonuclease protection assays (RPA) were performed to quantify mu-opioid receptor mRNA expression in specific brain regions of day 70 Rhesus Macaque fetuses that were exposed to cocaine (3 mg/kg) or saline from days 22-70 of gestation [6].

Anatomical context of OPRM1

• The decrease in mu-opioid receptor-like immunoreactivity was more pronounced in the monkey than in the rat dorsal root ganglia and spinal cord [2].
• Our results show that many small neurons in rat and monkey dorsal root ganglia, and some medium-sized and large neurons in rat dorsal root ganglia, express mu-opioid receptor-like immunoreactivity [2].
• The goal of this study was to assess the potential utility of cumulative-dosing procedures to evaluate the endocrine effects of mu opioid receptor ligands [7].
• The relative proportions of MOR, KOR, and DOR in the cortex were 28, 41, and 31% and in the thalamus were 60, 31, and 9% [8].
• Comparative analysis of Ki values with in vivo potency in the mouse tail flick test indicated a high degree of correlation between antinociception and affinity in the mu-opioid receptor cell line (r2 = 0.83, p < 0.0001) [9].

Associations of OPRM1 with chemical compounds

• The effects of CCAM, an insurmountable mu opioid receptor antagonist, were studied on the intravenous self-administration and thermoantinociception of alfentanil and nalbuphine, high- and low-efficacy opioid agonists, respectively, in rhesus monkeys [10].
• The mu opioid receptor agonist methadone (0.001-0.3 mg/ml) and the prototypic bitter substance quinine (0.001-0.3 mg/ml) failed to produce preferences for drug or water [11].
• Together, these data suggest that MOR, not other opioid receptor types or histamine, mediates scratching evoked by opioid analgesics [12].
• The aim of this study was to investigate the relative density of micro -, kappa-, and delta-opioid receptors (MOR, KOR, and DOR) and guanosine 5'-O-(3-[35S]thio)triphosphate ([35S]GTPgammaS) binding stimulated by full agonists in cortical and thalamic membranes of monkeys [8].
• Intrathecal (i.t.) administration of peptidic MOR agonist [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO, 0.00032-0.01 mg) evoked scratching, but i.v. DAMGO (0.01-1 mg/kg) did not increase scratching [12].

Analytical, diagnostic and therapeutic context of OPRM1

• Two mu-opioid receptor coding regions isolated from a single heterozygous (C77/G77) rhesus monkey brain were expressed in HEK-293 cells and characterized in radioreceptor assays [3].
• To understand the role of opioids and their receptors in chronic pain following peripheral nerve injury, we have studied the mu-opioid receptor in rat and monkey lumbar 4 and 5 dorsal root ganglion neurons and the superficial dorsal horn of the spinal cord under normal circumstances and after peripheral axotomy [2].

References