No genetic association between A118G polymorphism of μ-opioid receptor gene and schizophrenia and bipolar disorders.
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ABSTRACT: Background
Schizophrenia (SZ) and bipolar disorder (BD) are chronic and multifactorial psychiatric disorders that might be affected by different genes in combination with environmental factors. There is evidence of association between polymorphisms of μ-opioid receptor gene (OPRM1) with these disorders.Objectives
The aim of this study was to investigate the genetic association between OPRM1 A118G SNP in SZ and BD patients in comparison with healthy controls (HCs).Materials and methods
One single-nucleotide polymorphism in OPRM1 was genotyped using TaqMan real-time PCR assay in 203 SZ and BD patients and 389 HCs.Results
There was no statistically significant difference in genotypic and allelic frequencies of OPRM1 A118G SNP between HCs and SZ/BD patients.Conclusions
To find the underlying genetic factors associated with these complex disorders, further studies need to be conducted using larger sample size, different genetic populations, and different gene variations.
SUBMITTER: Yazdani S
PROVIDER: S-EPMC5806329 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background and objectWhether opioid-receptor mu 1 (OPRM1) A118G polymorphism (rs1799971) is associated with nicotine dependence is controversial. We analyzed the combined results from published studies of this possibility.MethodsLiterature reviews were performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Web of Science, Chinese National Science Infrastructure (CNKI), PubMed, Embase and Google Scholar database searches using MeSH terms were conducted to find all relevant researches up to October 2016. Odds ratios (ORs) and their 95% confidence intervals (95% CIs) were calculated in allele, homozygote, heterozygote, dominant and recessive models. Ethnicity-specific subgroup meta-analysis, heterogeneity, sensitivity analysis and publication bias were considered.ResultsSeven eligible studies with 3313 patients were included. The ORs in the five genetic models mentioned above were 1.000 (95% CI: 0.906, 1.104; p = 0.999), 1.032 (95% CI: 0.771, 1.381; p = 0.834), 0.963 (95% CI: 0.799, 1.162; p = 0.696), 1.006 (95% CI: 0.916, 1.104; p = 0.907), 0.967 (95% CI: 0.715, 1.309; p = 0.830), respectively. Only in dominant model is the association significant. Upon ethnicity-specific subgroup analysis, there is no statistical significance.ConclusionOPRM1-A118G polymorphism (A>G) is not associated with nicotine dependence.
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Project description:Mu opioid receptors are critical for heroin dependence, and A118G SNP of the mu opioid receptor gene (OPRM1) has been linked with heroin abuse. In our population of European Caucasians (n = 118), approximately 90% of 118G allelic carriers were heroin users. Postmortem brain analyses showed the OPRM1 genotype associated with transcription, translation, and processing of the human striatal opioid neuropeptide system. Whereas down-regulation of preproenkephalin and preprodynorphin genes was evident in all heroin users, the effects were exaggerated in 118G subjects and were most prominent for preproenkephalin in the nucleus accumbens shell. Reduced opioid neuropeptide transcription was accompanied by increased dynorphin and enkephalin peptide concentrations exclusively in 118G heroin subjects, suggesting that the peptide processing is associated with the OPRM1 genotype. Abnormal gene expression related to peptide convertase and ubiquitin/proteosome regulation was also evident in heroin users. Taken together, alterations in opioid neuropeptide systems might underlie enhanced opiate abuse vulnerability apparent in 118G individuals.
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Project description:BACKGROUND:OPRM1-A118G polymorphism (A > G, rs1799971) is associated with interindividual variability in both response to postoperative pain and opioid treatment. The aim of this meta-analysis is to identify the predictive strength in the current literature of OPRM1-A118G polymorphism to postoperative anesthetic reactions, including nausea, vomiting, pruritus and dizziness. METHODS:PubMed, EMBASE, Cochrane Library, Web of Knowledge, Google Scholar and CNKI database were searched to find gene-association researches exploring the impacts of OPRM1-A118G polymorphism on postoperative side effects (time: up to July 2016). Odd ratios (ORs) with 95% confidence intervals (95% CIs) were estimated in allele model, homozygote model, heterozygote model, dominant model and recessive model. Sensitivity analysis and potential bias were also assessed. RESULTS:137 articles were retrieved from databases. 17 eligible studies, including 4690 patients were considered in the meta-analysis. The ORs with 95% CIs of postoperative nausea, vomiting, nausea and vomiting (PONV), pruritus and dizziness in the five genetic models mentioned above were determined. Postoperative vomiting was significantly associated with OPRM1-A118G polymorphism in homozygote (OR: 0.422; 95% CI: 0.254, 0.701; P = 0.001), dominant (OR: 0.765; 95% CI: 0.592, 0.987; P = 0.040) and recessive (OR: 0.439; 95% CI: 0.268, 0.717; P = 0.001) models. The 118G allele was associated with a reduced risk of vomiting. No other associations were detected. There was no evidence of publication bias. CONCLUSIONS:OPRM1-A118G polymorphism (A > G) is associated with a reduced risk of postoperative vomiting, but not nausea, pruritus and dizziness. The results should be interpreted with caution due to limited sample and possible heterogeneity between the included studies. Well-designed and large-scale studies are necessary to confirm our results.
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Project description: Not available
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Project description:The A118G SNP (single nucleotide polymorphism) of the hMOPR [human MOPR (μ opioid receptor)] gene OPRM1 results in an amino acid substitution (N40D). Subjects homozygous for the 118G allele have been reported to require higher morphine doses to achieve adequate analgesia, and the 118G allele is more prevalent among drug abusers. However, changes in the MOPR protein associated with this SNP are unknown. Using a knockin mouse model (G/G mice; mice homozygous for the 112G allele of MOPR) that possesses the equivalent nucleotide/amino acid substitution (A112G; N38D) of the A118G SNP in the hMOPR gene, we investigated the N-linked glycosylation status of thalamic and striatal MOPR in G/G mice compared with A/A mice (wild-type mice homozygous for the 112A allele of MOPR). The molecular mass of MOPR determined by immunoblotting was lower in G/G mice than in A/A mice. Following treatment with peptide N-glycosidase F, which removes all N-linked glycans, both MOPR variants had an identical molecular mass, indicating that this discrepancy was due to a lower level of N-glycosylation of the MOPR in G/G mice. In Chinese-hamster ovary cells stably expressing hMOPRs, 118G/Asp40-hMOPR had a lower molecular mass than 118A/Asn40-hMOPR, which was similarly due to differential N-glycosylation. Pulse-chase studies revealed that the half-life of the mature form of 118G/Asp40-hMOPR (~12 h) was shorter than that of 118A/Asn40-hMOPR (~28 h). Thus the A118G SNP reduces MOPR N-glycosylation and protein stability.
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Project description:The A118G single-nucleotide polymorphism (SNP rs1799971) in the μ-opioid receptor gene, OPRM1, has been much studied in relation to alcohol use disorders. The reported effects of allelic variation at this SNP on alcohol-related behaviors, and on opioid receptor antagonist treatments, have been inconsistent. We investigated the pharmacogenetic interaction between A118G variation and the effects of two μ-opioid receptor antagonists in a clinical lab setting. Fifty-six overweight and moderate-heavy drinkers were prospectively stratified by genotype (29 AA homozygotes, 27 carriers of at least 1 G allele) in a double-blind placebo-controlled, three-period crossover design with naltrexone (NTX; 25 mg OD for 2 days, then 50 mg OD for 3 days) and GSK1521498 (10 mg OD for 5 days). The primary end point was regional brain activation by the contrast between alcohol and neutral tastes measured using functional magnetic resonance imaging (fMRI). Secondary end points included other fMRI contrasts, subjective responses to intravenous alcohol challenge, and food intake. GSK1521498 (but not NTX) significantly attenuated fMRI activation by appetitive tastes in the midbrain and amygdala. GSK1521498 (and NTX to a lesser extent) significantly affected self-reported responses to alcohol infusion. Both drugs reduced food intake. Across all end points, there was less robust evidence for significant effects of OPRM1 allelic variation, or for pharmacogenetic interactions between genotype and drug treatment. These results do not support strong modulatory effects of OPRM1 genetic variation on opioid receptor antagonist attenuation of alcohol- and food-related behaviors. However, they do support further investigation of GSK1521498 as a potential therapeutic for alcohol use and eating disorders.
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