Catechol-O-methyl transferase

About: Catechol-O-methyl transferase is a research topic. Over the lifetime, 1646 publications have been published within this topic receiving 87360 citations.

Tolcapone suppresses ethanol intake in alcohol-preferring rats performing a novel cued access protocol.

Abstract: Background Dopamine (DA) has been shown to play a central role in regulating motivated behavior and encoding reward. Chronic drug abuse elicits a state of hypodopaminergia in the mesocorticolimbic (MCL) system in both humans and preclinical rodent models of addiction, including those modeling alcohol use disorders (AUD). Methods Working under the hypothesis that reductions in the bioavailability of DA play an integral role in the expression of the excessive drinking phenotype, the catechol-O-methyltransferase (COMT) inhibitor tolcapone was used as a means to amplify cortical DA concentration and drinking behaviors were then assessed. Sucrose and ethanol (EtOH) consumption were measured in P and Wistar rats in both a free choice drinking protocol and a novel cued access protocol. Results Tolcapone attenuated the consumption of EtOH, and to a lesser extent sucrose, in P rats in the cued access protocol, while no effect was observed in the free choice drinking protocol. Tolcapone also decreased EtOH consumption in high drinking Wistar rats. A follow-up experiment using the indirect DA agonist d-amphetamine showed no change in EtOH consumption. Conclusions Collectively, these data suggest that COMT inhibitors may be capable of alleviating the extremely motivating or salient nature of stimuli associated with alcohol. The hypothesis is put forth that the relative specificity of tolcapone for cortical DA systems may mediate the suppression of the high seeking/drinking phenotype.

No association of COMT (Val158Met) genotype with brain structure differences between men and women.

Abstract: We examined the effect of the catechol-O-methyltransferase (COMT) Val158Met polymorphism (rs4680), on brain structure in a subset (N = 82) of general population members of the Northern Finland 1966 Birth Cohort, selected through a randomization procedure, aged 33-35. Optimised voxel-based morphometry was used to produce grey matter maps from each subject's high resolution T1 weighted brain magnetic resonance images, which were subsequently entered into a general linear model with COMT genotype as defined by Met allele loading, gender and genotype by gender interaction as independent variables. Additional analyses were carried out on grey matter volumes within the dorsal lateral pre-frontal cortex (DLPFC) to examine effects on overall DLPFC volume and also using the DLPFC as a mask for voxelwise analyses, as this is an area previously reported as associated with Met allele loading. We failed to find any statistically significant association with grey matter volume and Met allele loading in the COMT gene or interaction affects between COMT and gender in either the whole brain voxel-wise analysis or in the area of the DLPFC.

Differential effects of the catechol-O-methyltransferase Val158Met genotype on the cognitive function of schizophrenia patients and healthy Japanese individuals.

Abstract: BackgroundThe functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene has been associated with differences in prefrontal cognitive functions in patients with schizophrenia and healthy individuals. Several studies have indicated that the Met allele is associated with better performance on measures of cognitive function. We investigated whether the COMT Val158Met genotype was associated with cognitive function in 149 healthy controls and 118 patients with schizophrenia. MethodsCognitive function, including verbal memory, working memory, motor speed, attention, executive function and verbal fluency, was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS-J). We employed a one-way analysis of variance (ANOVA) and a multiple regression analysis to determine the associations between the COMT Val158Met genotype and the BACS-J measurements. ResultsThe one-way ANOVA revealed a significant difference in the scores on the Tower of London, a measure of executive function, between the different Val158Met genotypes in the healthy controls (p = 0.023), and a post-hoc analysis showed significant differences between the scores on the Tower of London in the val/val genotype group (18.6 ± 2.4) compared to the other two groups (17.6 ± 2.7 for val/met and 17.1 ± 3.2 for met/met; p = 0.027 and p = 0.024, respectively). Multiple regression analyses revealed that executive function was significantly correlated with the Val158Met genotype (p = 0.003). However, no evidence was found for an effect of the COMT on any cognitive domains of the BACS-J in the patients with schizophrenia. ConclusionThese data support the hypothesis that the COMT Val158Met genotype maintains an optimal level of dopamine activity. Further studies should be performed that include a larger sample size and include patients on and off medication, as these patients would help to confirm our findings.

Comprehensive Assessment of Genetic Variation of Catechol-O-Methyltransferase and Breast Cancer Risk

Abstract: Because catechol-O-methyltransferase (COMT) catalyzes the addition of methyl groups to stabilize catechol estrogens that may induce DNA damage, genetic variants could influence breast cancer risk. To comprehensively characterize genetic variation in this gene, we selected haplotype-tagging single nucleotide polymorphisms (htSNP) in COMT. A total of 11 htSNPs (including COMT Val158Met) were selected based on the resequencing and dense genotyping approach of the Breast and Prostate Cancer Cohort Consortium. htSNPs were genotyped in a population-based, case-control study in Poland (1,995 cases and 2,296 controls). Individual SNPs were not significantly associated with risk. Haplotypes were estimated using the expectation-maximization algorithm. Overall differences in the haplotype distribution between cases and controls were assessed using a global score test. The TGAG haplotype (frequent in 4.3% of controls), in a linkage disequilibrium (LD) block that included the 3′ untranslated region (UTR) of COMT, was associated with breast cancer risk (odds ratio, 1.29; 95% confidence interval, 1.06-1.58) compared with the most common haplotype TGAA; however, the global test for haplotype associations was not significant (P = 0.09). Haplotypes in another LD block, which included COMT Val158Met, were not associated with breast cancer risk (global P = 0.76). Haplotype-breast cancer risk associations were not significantly modified by hormonally related risk factors, family history of breast cancer, or tumor characteristics. In summary, our data does not support a substantial overall association between COMT haplotypes and breast cancer. The suggestion of increased risk associated with a haplotype in the 3′ UTR of COMT needs to be confirmed in independent study populations. (Cancer Res 2006; 66(19): 9781-5)