OBJECTIVES: The aim of the present study is to explore the effect of fluoxetine on transcription, translation and activity of tryptophan hydroxylase (TPH), and intracellular level of serotonin. METHODS: The expression level of the TPH mRNA and the protein, the TPH enzyme activity, and the intracellular level of serotonin were explored at the fluoxetine-treated RBL-2H3 cells. Real-time RT-PCR and immunoblotting analysis confirmed changes in the expression of TPH mRNA and protein. The activity of TPH was measured using [3H]tryptophan. The intracellular level of serotonin was measured by HPLC. RESULTS: The TPH activity was gradually increased on time from 24hr to 72hr. The real-time RT-PCR also revealed that the TPH mRNA was increased at 12, 24 and 72hr in the fluoxetine-treated RBL-2H3 cells. The immunoblotting analysis also revealed that the TPH protein was decreased at 72hr in the fluoxetine-treated RBL-2H3 cells. The intracellular level of serotonin was increased at 48hr after treatment of fluoxetine. CONCLUSION: Fluoxetine induced the increases of the TPH mRNA, the TPH enzyme activity and intracellular level of serotonin, and the decrease of the TPH protein expression at the RBL- 2H3 cells.
Chromatography, High Pressure Liquid ; Fluoxetine ; Immunoblotting ; RNA, Messenger ; Serotonin ; Tryptophan Hydroxylase* ; Tryptophan*

OBJECTIVES: Tardive dyskinesia (TD) is a serious and sometimes irreversible adverse effect that may develop during long-term antipsychotics treatment. Previous studies have suggested that brain serotonergic systems are related to TD vulnerability and tryptophan hydroxylase (TPH) is the rate limiting enzyme in the biosynthesis of serotonin. This study aimed to investigate the association between TPH2 gene -703G/T polymorphism (rs4570625) and antipsychotic-induced TD in the Korean schizophrenia patients. METHODS: We investigated whether TPH2 gene -703G/T polymorphism is associated with antipsychotic-induced TD in 280 Korean schizophrenia patients. The subjects with TD (n=105) and without TD (n=175) were matched for antipsychotic drug exposure and other relevant variables. RESULTS: There was no significant difference in the distribution of genotypic (chi2=3.00, p=0.223) and allelic (chi2=0.19, p=0.661) frequencies between patients group with TD and without TD. There was no significant difference in total Abnormal Involuntary Movement Scale score (F=1.95, p=0.362) among the genotype groups, either. CONCLUSIONS: The present study does not support that TPH2 gene -703G/T polymorphism is involved in TD of the Korean schizophrenia subjects.
Antipsychotic Agents ; Brain ; Dyskinesias ; Genotype ; Humans ; Movement Disorders ; Schizophrenia ; Serotonin ; Tryptophan ; Tryptophan Hydroxylase

OBJECTIVES: Tardive dyskinesia (TD) is a serious and sometimes irreversible adverse effect that may develop during long-term antipsychotics treatment. Previous studies have suggested that brain serotonergic systems are related to TD vulnerability and tryptophan hydroxylase (TPH) is the rate limiting enzyme in the biosynthesis of serotonin. This study aimed to investigate the association between TPH2 gene -703G/T polymorphism (rs4570625) and antipsychotic-induced TD in the Korean schizophrenia patients. METHODS: We investigated whether TPH2 gene -703G/T polymorphism is associated with antipsychotic-induced TD in 280 Korean schizophrenia patients. The subjects with TD (n=105) and without TD (n=175) were matched for antipsychotic drug exposure and other relevant variables. RESULTS: There was no significant difference in the distribution of genotypic (chi2=3.00, p=0.223) and allelic (chi2=0.19, p=0.661) frequencies between patients group with TD and without TD. There was no significant difference in total Abnormal Involuntary Movement Scale score (F=1.95, p=0.362) among the genotype groups, either. CONCLUSIONS: The present study does not support that TPH2 gene -703G/T polymorphism is involved in TD of the Korean schizophrenia subjects.
Antipsychotic Agents ; Brain ; Dyskinesias ; Genotype ; Humans ; Movement Disorders ; Schizophrenia ; Serotonin ; Tryptophan ; Tryptophan Hydroxylase

Alcohol abuse and cigarette smoking have been on the rise worldwide and it has been reported that alcohol and nicotine influence serotonergic neuronal activity in the dorsal raphe. Serotonin (5-hydroxytryptamine, 5-HT) has been implicated in the pathophysiology of various neuropsychiatric disorders. In the present study, the effects of alcohol and nicotine on the synthesis of 5-HT and the expression of tryptophan hydroxylase (TPH), the rate limiting enzyme of 5-HT synthesis, in the dorsal and median raphe of young rats were investigated via immunohistochemistry. The numbers of the 5-HT-positive and TPH-positive cells in raphe nuclei were reduced by alcohol and nicotine treatment, and these numbers were reduced more potently by co-administration of alcohol and nicotine. Based on the results, it can be suggested that the pathogenesis of alcohol- and nicotine-induced neuropsychological disorders involves alcohol- and nicotine-induced suppression of 5-HT synthesis and TPH expression in raphe, and that this may be of particular relevance in the consumption of alcohol and nicotine during adolescence.
Adolescent ; Alcoholism ; Animals ; Humans ; Immunohistochemistry ; Nicotine* ; Raphe Nuclei ; Rats* ; Serotonergic Neurons ; Serotonin* ; Smoking ; Tryptophan Hydroxylase* ; Tryptophan*

The biogenic monoamine 5-hydroxytryptamine (5-HT) is an ancient intracellular signaling molecule widely distributed in all animals with nervous systems, and has been implicated in principal behaviors. Tryptophan hydroxylase (TRH) induces a highly specific catalytic reaction that converts L-tryptophan (tryptophan) to 5-hydroxy-L-tryptophan (5-HTP) that is subsequently used as a substrate by aromatic L-amino acid decarboxylase (DDC) to form 5-HT. Five-HT is an ancient intracellular signaling molecule that is widely distributed in the animal kingdom and has been implicated in regulating the behaviors of animals with nervous systems. However, the role of TRH in Lepidoptera is not well understood. In this study, we cloned 1 667 bp cDNAs of Bombyx mori TRH (BmTRH), which contains a 1 632 bp open reading frame (ORF). Homology analysis revealed that BmTRH shared high amino acid identity with Homo sapiens TPH and Drosophila TRH (DmTRH). The high homology (70%) of BmTRH with DmTRH suggested that BmTRH could have a function similar to DmTRH. Gene expression analysis revealed that BmTRH was mainly expressed in head and central nervous (CNS). Moreover, immunohistochemistry and Western blotting analyses showed that BmTRH was detected only in larval nervous tissues. Taken together, our results indicate that BmTRH could likely function in the regulation of neural activities in B. mori. The transcripts of B. mori decarboxylase (BmDDC) and B. mori phenylalanine hydroxylase (BmPAH) whose proteins had TRH activity, were also expressed in the CNS tissues, indicating that unlike in Drosophila, two distinct mechanisms likely regulate 5-HT synthesis in silkworm.
Amino Acid Sequence ; Animals ; Bombyx ; Cloning, Molecular ; DNA, Complementary ; Insect Proteins ; Phenylalanine Hydroxylase ; Tryptophan Hydroxylase

OBJECTIVE: This study has been carried out to explore the genetic causes of bipolar disorder by comparing the frequency of Tryptophan Hydroxylase (TPH) A218C polymorphism between bipolar disorder patients and normal controls, and to explore the relation between clinical characteristics of bipolar disorder patients and TPH polymorphism. METHODS: The genotype and allele frequencies of TPH in the genome of 113 hospitalized patients with bipolar disorder was compared with those of 124 normal control subjects using polymerase chain reaction and restriction fragment length polymorphism. The association between TPH A218C polymorphism and clinical characteristics in bipolar disorder patients were explored. RESULTS: The distributions of TPH A218C polymorphism between the patients with bipolar disorder and normal control subjects show no difference statistically. There was a significant difference in the distribution of TPH genotype by clinical characteristics. The frequency of C allele is significantly higher in patients with a history of suicidal attempts. The frequency of A allele is significantly higher in patients with family history of bipolar disorder. CONCLUSION: This study suggests that suicidal attempts and family history in the patients with bipolar disorder are clearly associated with TPH A218C polymorphism and may explain, in part, the biological basis for these typologies.
Alleles ; Bipolar Disorder* ; Gene Frequency ; Genome ; Genotype ; Humans ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Suicide ; Tryptophan Hydroxylase* ; Tryptophan*

OBJECTIVE: The aim of the present study was to examine the association between serotonin-related gene polymorphisms and bipolar disorder in the Korean population. In addition, we sought to explore the relationship between the clinical characteristics of bipolar patients and serotonin-related gene polymorphisms. METHODS: Inpatients with bipolar disorder (n=103) and control subjects (n=86) were genotyped for 5HT2A 1438A/G, tryptophan hydroxylase 1 (TPH1) 218 A/C, and TPH2 703G/T. We divided patients with bipolar disorder into two groups according to the presence of psychotic symptoms. The severity of their symptoms was measured using the Young Mania Rating Scale (YMRS) and the Brief Psychiatric Rating Scale (BPRS). RESULTS: There were no significant differences in the genotype distributions or allelic frequencies in the three serotonergic polymorphisms between patients with bipolar disorder and normal controls. There were significant differences in genotype distributions and allele frequencies of the 5-HT2A -1438A/G polymorphism between the psychotic mania group and the non-psychotic mania group (genotype: chi-square=7.50, p=0.024; allele: chi-square=5.92, p=0.015). However, after Bonferroni correction this signifact difference disappeared. We did not find significant differences in the genotype distributions or allelic frequencies in the TPH1 218 A/C and TPH2 703G/T polymorphisms between the psychotic mania group and non-psychotic mania group. CONCLUSION: We failed to found the statistically significant association between three polymorphisms and bipolar disorder. However, there was a trend towards association between 5-HT2A -1438A/G polymorphism and psychotic symptom in bipolar disorder. Future research should seek to clarify this association.
Bipolar Disorder ; Brief Psychiatric Rating Scale ; Gene Frequency ; Genotype ; Humans ; Inpatients ; Serotonin ; Tryptophan Hydroxylase

One of hypothesis is that sleep loss related to a decrease in serotonergic activity plays a significant role in attempted suicide. A growing evidence suggests that central serotonergic activity plays a key role in the etiology of suicide. It has been reported that the cerebrospinal fluid (CSF) levels of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin, were reduced in suicide attempters. In addition, there is evidence that tryptophan hydroxylase is associated with suicide. The association between sleep and suicide was also suggested by some researchers. Several recent studies have showed the association between sleep disturbance and suicide rates in patients with mental disorders and in a general population. In addition, it has been suggested that serotonin plays a role in maintaining arousal and regulating muscle tone and in regulating some of the phasic events of REM sleep. Especially, it is well-known that 5-HT2 receptors are related to slow wave sleep. In conclusion, it is clear that sleep, serotonin activity, and suicide are linked, although the direction of causation needs clarification. In future, large population-based cohort studies are needed to demonstrate the direction of causation in the relationships between sleep, serotonin activity, and suicide.
Arousal ; Cohort Studies ; Humans ; Mental Disorders ; Muscles ; Serotonin ; Sleep, REM ; Suicide ; Suicide, Attempted ; Tryptophan Hydroxylase

The current study was aimed to investigate the potential effects of perinatal exposure to therapeutic dose of penicillin and cefixime on the cognitive behaviors, gastrointestinal (GI) motility and serum 5-hydroxytryptamine (5-HT) level in the offspring. Pregnant rats were continuously treated with cefixime or penicillin in the period between 1 week before and 1 week after labor. Behavior tests, including social preference, self-grooming and elevated plus maze tests, and intestinal motility tests were carried out on the offspring at age of 4 to 10 weeks. Serum 5-HT levels were detected with ELISA, and potassium/sodium hyperpolarization activated cyclic nucleotide-gated channel 2 (HCN2) and tryptophan hydroxylase 1 (TPH1) expression levels in colon epithelium of offspring were detected by Western blot and RT-qPCR. The results showed that, compared with the naive group, cefixime increased social behavior in the female offspring, but did not affect the male offspring. Compared with the naive group, cefixime significantly decreased colonic and intestinal transits, and increased cecum net weight and standardized cecum net weight in the male offspring, but did not affect the female offspring. The serum 5-HT levels in the male offspring, rather than the female offspring, in cefixime and penicillin groups were significantly increased compared with that in the naive group. The protein expression level of HCN2 in colon epithelium of the offspring in cefixime group was significantly down-regulated, and the TPH1 expression level was not significantly changed, compared with that in the naive group. These results suggest that perinatal antibiotics exposure may affect neural development and GI functions of the offspring, and the mechanism may involve peripheral 5-HT and gender-dependent factor.
Animals ; Anti-Bacterial Agents ; pharmacology ; Colon ; Female ; Gastrointestinal Motility ; Male ; Mice ; Pregnancy ; Rats ; Serotonin ; Tryptophan Hydroxylase

OBJECTIVE: To investigate the polymorphism of the TPH gene T3792A locus in Han ethnic group of north China and its application value in forensic science. METHODS: The polymorphism of T3792A locus of the TPH gene was analyzed by the ASPCR of blood samples from 173 unrelated individuals of north Chinese Han population. RESULTS: The distribution of the T3792A locus polymorphism of the TPH gene in Han ethnic group of north China followed the Hardy-Weinberg law, with the allele A and T gene frequency of 0.486 and 0.514, respectively. CONCLUSION The TPH gene T3792A locus shows a very good genetic polymorphism, and may be applied to individual identification and paternity testing.
Asian People/genetics* ; China/ethnology* ; Forensic Genetics ; Gene Frequency ; Humans ; Paternity ; Polymorphism, Genetic ; Tryptophan Hydroxylase/genetics*