Dopamine (DA), as a catecholamine neurotransmitter widely distributed in the central nervous system and the peripheral tissues, has attracted a lot of attention. Especially in recent years, DA has been found to regulate the function of the immune system, and the involvement of DA in the intestinal mucosal inflammation-related diseases has become a hot research topic. The digestive tract is an important source of peripheral DA, and DA is not only produced in the enteric nervous system and gastrointestinal epithelium, but also produced by intestinal microorganisms. In addition to the synthetases of DA, the DA contents in body tissues are also affected by the two kinds of metabolic enzymes, monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). This article reviewed the sources, metabolism, and functions of DA in digestive tract, especially focusing on the distribution and function of MAO and COMT, the enzymes degrading DA.
Catechol O-Methyltransferase ; Catechol O-Methyltransferase Inhibitors ; Dopamine ; Gastrointestinal Tract ; Monoamine Oxidase ; Monoamine Oxidase Inhibitors

OBJECTIVE: To investigate the association of genetic polymorphisms of norepinephrine metabolizing enzymes with postpartum depression and analyze the risk factors for postpartum depression in women following cesarean section. METHODS: A total of 591 Chinese woman of Han Nationality undergoing caesarean section were enrolled in this study. The diagnosis of postpartum depression was established for an Edinburgh Postnatal Depression Scale (EPDS) score ≥9. For all the women without antepartum depression, the genotypes of catechol-O-methyltransferase (COMT; at 5 sites including rs2020917 and rs737865) and monoamine oxidase A (rs6323) were determined using Sequenom Mass Array single nucleotide polymorphism (SNP) analysis. We analyzed the contribution of the genetic factors (SNPs, linkage disequilibrium and haplotype) to postpartum depression and performed logistic regression analysis to identify all the potential risk factors for postpartum depression and define the interactions between the genetic and environmental factors. RESULTS: The incidence of postpartum depression was 18.1% in this cohort. Univariate analysis suggested that COMT polymorphism at rs2020917 (TT genotype) and rs737865 (GG genotype) were significantly correlated with the occurrence of postpartum depression ( < 0.05). Logistic regression analysis showed that COMT polymorphism at rs2020917 (TT genotype) and rs737865 (GG genotype), severe stress during pregnancy, and domestic violence were the risk factors for postpartum depression ( < 0.05); no obvious interaction was found between the genetic polymorphisms and the environmental factors in the occurrence of postpartum depression. CONCLUSIONS The rs2020917TT and rs737865GG genotypes of COMT, stress in pregnancy, and domestic violence are the risk factors for postpartum depression.
Catechol O-Methyltransferase ; genetics ; Cesarean Section ; adverse effects ; Depression, Postpartum ; diagnosis ; enzymology ; genetics ; Domestic Violence ; psychology ; Female ; Gene-Environment Interaction ; Genotype ; Haplotypes ; Humans ; Linkage Disequilibrium ; Monoamine Oxidase ; genetics ; Norepinephrine ; metabolism ; Polymorphism, Single Nucleotide ; Postoperative Complications ; diagnosis ; enzymology ; genetics ; Pregnancy ; Pregnancy Complications ; etiology ; psychology ; Risk Factors ; Stress, Psychological

Although the majority of patients with schizophrenia are not actually violent, an increased tendency toward violent behaviors is known to be associated with schizophrenia. There are several factors to consider when identifying the subgroup of patients with schizophrenia who may commit violent or aggressive acts. Comorbidity with substance abuse is the most important clinical indicator of increased aggressive behaviors and crime rates in patients with schizophrenia. Genetic studies have proposed that polymorphisms in the promoter region of the serotonin transporter gene and in the catechol-O-methyltransferase gene are related to aggression. Neuroimaging studies have suggested that fronto-limbic dysfunction may be related to aggression or violence. By identifying specific risk factors, a more efficient treatment plan to prevent violent behavior in schizophrenia will be possible. Management of comorbid substance use disorder may help prevent violent events and overall aggression. Currently, clozapine may be the only effective antipsychotic medication to repress aggressive behavior. With the current medical field moving toward tailored medicine, it is important to identify vulnerable schizophrenia populations and provide efficient treatment.
Aggression ; Antipsychotic Agents ; Catechol O-Methyltransferase ; Clozapine ; Comorbidity ; Crime ; Humans ; Neuroimaging ; Promoter Regions, Genetic ; Risk Factors ; Schizophrenia ; Serotonin Plasma Membrane Transport Proteins ; Substance-Related Disorders ; Violence

Parkinson's disease is one of the most common neurodegenerative disorders world widely. Although curable therapies are practically not available yet, symptomatic managements using anti-Parkinson medications have shown to be quite effective to improve patients' quality of life. The discovery of dopaminergic deficits in Parkinson's disease in 1960s have brought about the human clinical trials of levodopa, which opened an “Era of Dopamine” in treatment history of the Parkinson's disease. Levodopa still remains gold standard. Dopamine agonists have proved their efficacies and delayed the development of long-term complications of levodopa use. Inhibitors of respective enzyme monoamine oxidase-B and catechol-O-methyltransferase, anticholinergics, and amantadine strengthen the therapeutic effects via either monotherapy or adjunctive way. Strategy of continuous dopaminergic stimulation and disease modification are weighing in current advances. This article is providing evidence-based review of pharmacological treatment of Parkinson's disease from early to advanced stages as well as management its unavoidable adverse reactions.
Amantadine ; Catechol O-Methyltransferase ; Cholinergic Antagonists ; Dopamine Agonists ; Drug Therapy ; Humans ; Levodopa ; Neurodegenerative Diseases ; Parkinson Disease ; Quality of Life ; Therapeutic Uses

OBJECTIVE: Family and twin studies have suggested genetic liability for panic disorder (PD) and therefore we sought to determine the role of noradrenergic and serotonergic candidate genes for susceptibility for PD in a Japanese population. METHODS: In this age- and gender-matched case-control study involving 119 PD patients and 119 healthy controls, we examined the genotype distributions and allele frequencies of the serotonin transporter gene linked polymorphic region (5-HTTLPR), −1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (5-HT1A), and catechol-O-methyltransferase (COMT) gene polymorphism (rs4680) and their association with PD. RESULTS: No significant differences were evident in the allele frequencies or genotype distributions of the COMT (rs4680), 5-HTTLPR polymorphisms or the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients and controls. Although there were no significant associations of these polymorphisms with in subgroups of PD patients differentiated by gender or in subgroup comorbid with agoraphobia (AP), significant difference was observed in genotype distributions of the −1019C/G (rs6295) promoter polymorphism of 5-HT1A between PD patients without AP and controls (p=0.047). CONCLUSION: In this association study, the 1019C/G (rs6295) promoter polymorphism of the 5-HT1A receptor G/G genotype was associated with PD without AP in a Japanese population.
Agoraphobia ; Asian Continental Ancestry Group ; Case-Control Studies ; Catechol O-Methyltransferase* ; Gene Frequency ; Genotype ; Humans ; Panic Disorder* ; Panic* ; Polymorphism, Genetic* ; Receptor, Serotonin, 5-HT1A* ; Serotonin Plasma Membrane Transport Proteins ; Serotonin*

OBJECTIVE: Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Thus, the present study aimed to determine the effects of a single dose of methylphenidate (Mph) on neurometabolite levels according to polymorphisms of the catechol-O-methyltransferase (COMT) gene. METHODS: This study evaluated the neurometabolite levels including N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) of ADHD patients, before and after treatment with Mph (10 mg) according to the presence of COMT polymorphisms. The spectra were obtained from the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), cerebellum, and striatum. RESULTS: The NAA levels of the val/val and val genotype carriers (val/val and val/met genotypes) increased in the DLPFC and ACC, respectively, following Mph treatment. The NAA/Cr ratio was lower in the DLPFC of val carriers than in the met/met genotype carriers prior to Mph administration. The Cho levels of the val/met genotype and val carriers increased in the striatum following Mph treatment. Following Mph treatment, the Cr levels of the met/met genotype carriers were higher than those of the val/met genotype and val carriers. Additionally, after Mph treatment, there was a significant increase in Cr levels in the DLPFC of the met/met genotype carriers but a significant decrease in such levels in the striatum of val/val genotype carriers. CONCLUSION: These findings suggest that polymorphisms of the COMT gene can account for individual differences in neuro-chemical responses to Mph among ADHD patients. Therefore, further studies are needed to fully characterize the effects of the Val158met polymorphism of the COMT gene on treatment outcomes in patients with ADHD.
Attention Deficit Disorder with Hyperactivity* ; Catechol O-Methyltransferase ; Cerebellum ; Choline ; Creatine ; Genotype ; Gyrus Cinguli ; Humans ; Individuality ; Magnetic Resonance Spectroscopy* ; Methylphenidate* ; Prefrontal Cortex

There is growing evidence of poor health-related quality of life (HRQOL) in patients with panic disorder (PD). However, little is known about the factors affecting HRQOL in patients with PD. The authors examined whether 5-HTTLPR tri-allelic approach and Cathechol-O-methyltransferase (COMT) Val(158)Met polymorphism can predict HRQOL in patients with PD controlling for sociodemographic factors and disorder-related symptom levels. The sample consisted of 179 patients with PD consecutively recruited from an outpatient clinic and age- and gender ratio-matched 110 healthy controls. The SF-36 was used to assess multiple domains of HRQOL. Hierarchical multiple regression analysis was performed to determine the independent effect of the 5-HTTLPR and COMT Val(158)Met on the SF-36 in panic patients. Patients with PD showed lowered HRQOL in all sub-domains of the SF-36 compared to healthy controls. The 5-HTTLPR independently and additively accounted for 2.2% of variation (6.7% of inherited variance) of perceived general health and the COMT Val(158)Met independently and additively accounted for 1.5% of variation (5.0% of inherited variance) of role limitation due to emotional problems in patient group. The present study suggests that specific genetic polymorphisms are associated with certain domains of HRQOL and provides a new insight on exploring the factors that predict HRQOL in patients with PD.
Adult ; Age Factors ; Alleles ; Case-Control Studies ; Catechol O-Methyltransferase/*genetics ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Panic Disorder/genetics/*pathology ; Polymorphism, Single Nucleotide ; *Quality of Life ; Regression Analysis ; Serotonin Plasma Membrane Transport Proteins/*genetics ; Sex Factors

PURPOSE: Alexithymia, defined as a deficit in the ability to recognize and describe one's own feelings, may be related to the development and maintenance of obsessive-compulsive symptoms. The aim of this study was to evaluate the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and alexithymia in patients with obsessive-compulsive disorder (OCD). MATERIALS AND METHODS: We recruited 244 patients with OCD (169 males, 75 females). Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20), and genotyping of the COMT Val(158)Met polymorphism was evaluated. RESULTS: Patients with the COMT Val/Val genotype had significantly higher total and "difficulty identifying feelings" (DIF) subdimension scores than those with the Val/Met or Met/Met genotypes. Patients with the COMT Val/Val genotype had significantly higher "difficulty describing feelings" (DDF) subdimension scores than those with the COMT Val/Met genotype. However, there were no differences in the scores for the "externally oriented thinking" (EOT) subdimension among the three genotypes. CONCLUSION: These results indicate that the high-activity Val allele of the COMT Val(158)Met polymorphism is associated with increased alexithymic traits in patients with OCD. The present finding suggests that alexithymia is an endophenotype of OCD that is mediated by the COMT Val(158)Met polymorphism.
Adult ; Affective Symptoms/*diagnosis/genetics/psychology ; Alleles ; Catechol O-Methyltransferase/*genetics ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Obsessive-Compulsive Disorder/*diagnosis/genetics/psychology ; Phenotype ; *Polymorphism, Genetic ; Republic of Korea

OBJECTIVE: ObjectiveaaWe evaluated the distribution of alpha-2A adrenergic receptor (ADRA2A) and catechol-o-methyltransferase (COMT) single nucleotide polymorphisms (SNPs) among ADHD subtypes and other homogeneous patient populations including treatment-resistant cases and patients with high symptom severity. METHODS: Methodsaa121 ADHD patients aged 6-18 years were included in the study. Diagnosis and subtypes designation were confirmed using the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and symptoms were evaluated using the Conners' Parent (CPRS) and Teacher Rating Scales (CTRS). The response to methylphenidate was assessed objectively using the Clinical Global Impression-Severity Scale (CGI-S) and Global Assessment of Functioning Scale (GAS) as well as the Continuous Performance (CPT) and Trail Making tests (TMT-A, B). Patients were genotyped for ADRA2A (rs1800544) and COMT (rs4680) SNPs by PCR/RFLP and compared to a gender-matched control group. RESULTS: Although there was no association of COMT (rs4680) SNP with symptoms or diagnosis, the ADRA2A polymorphism, low socioeconomic status (SES), and comorbid psychiatric diagnosis were all associated with poor response to methylphenidate in logistic regression analysis. CONCLUSION: Clinicians may consider adjuvant strategies when these negative factors are present to increase the success of tailored ADHD treatments in the future.
Appointments and Schedules ; Attention Deficit Disorder with Hyperactivity* ; Catechol O-Methyltransferase ; Diagnosis ; Genetic Variation* ; Genetics ; Humans ; Logistic Models ; Mental Disorders ; Methylphenidate ; Mood Disorders ; Parents ; Phenotype ; Polymorphism, Single Nucleotide ; Receptors, Adrenergic, alpha-2 ; Schizophrenia ; Social Class ; Trail Making Test ; Weights and Measures

Sexual orientation is influenced by both environmental factors and biological factors. Family and twin studies have shown that genetic factors play an important role in the formation of male homosexuality. Genome-wide scan also revealed candidate chromosomal regions which may be associated with male homosexuality, but so far no clearly related genes have been found. This article reviews the progress of relevant studies and candidate genes which are related to male homosexuality.
Animals ; Aromatase ; genetics ; Catechol O-Methyltransferase ; genetics ; Homosexuality, Male ; genetics ; Humans ; LIM-Homeodomain Proteins ; genetics ; Male ; Receptors, Dopamine D1 ; genetics ; Transcription Factors ; genetics