We organized a multicenter study of a relatively large sample of 519 patients with bipolar disord... more We organized a multicenter study of a relatively large sample of 519 patients with bipolar disorder (according to DSM-IV criteria) and 588 control subjects matched for gender, age, and ethnicity (Japanese). Genotyping was done by polymerase chain reactionbased restriction ...
Postmortem studies regarding schizophrenia revealed altered expression of genes related to gamma-... more Postmortem studies regarding schizophrenia revealed altered expression of genes related to gamma-amino butyric acid neurotransmission system. One of the most consistent findings is the reduced level of 67 kDa glutamic acid decarboxylase isoform (GAD(67)). Moreover, several studies reported positive associations between the GAD(67) gene (GAD1) and schizophrenia. These reasons, motivated us to carry out replication study regarding association between GAD1 (fourteen tagging SNPs) and schizophrenia in Japanese population (562 schizophrenic patients and 470 controls). However we couldn't confirm significant association that had been previously reported. Considering size of our sample and strategy that corresponds well with the approaches used in gene-based association analysis, our conclusion is that GAD1 does not play a major role in schizophrenia in Japanese population.
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2008
Selective serotonin reuptake inhibitor (SSRI)-induced nausea can be severe enough to lead to earl... more Selective serotonin reuptake inhibitor (SSRI)-induced nausea can be severe enough to lead to early treatment discontinuation. However, it is currently not possible to predict the occurrence of nausea before the initiation of SSRI treatment. In this study, we investigated the effect of genetic polymorphisms in the 5-hydroxytryptamine type 2A, 3A, and 3B (5-HT3B) receptors, 5-HT transporter, and CYP2D6 genes on the incidence of paroxetine-induced nausea. A consecutive series of 72 Japanese patients with depressive or anxiety disorders were treated with paroxetine. Paroxetine-induced nausea was assessed by a pharmacist and was observed in 29.2% of the patients. A significant (nominal p=0.00286) association was found between the incidence of nausea and the -100_-102AAG insertion/deletion polymorphism of the 5-HT3B receptor gene. No significant associations were observed between the other genetic polymorphisms and the incidence of nausea. The -100_-102AAG deletion variant of the 5-HT3B r...
Clinical Psychopharmacology and Neuroscience, 2015
Clozapine has been demonstrated to be useful for treating refractory schizophrenia. However, hype... more Clozapine has been demonstrated to be useful for treating refractory schizophrenia. However, hypersalivation occurs in 31.0- 97.4% of the patients treated with clozapine. Accordingly, some patients who are disturbed by their hypersalivation refuse to continue with clozapine treatment. This study investigated the efficacy of the anticholinergic agent scopolamine butylbromide against clozapine-induced hypersalivation. Five schizophrenia patients were coadministered scopolamine butylbromide (30-60 mg/ day) for 4 weeks. At the baseline and after 4 weeks' treatment, we subjectively evaluated hypersalivation using a visual analog scale and objectively assessed it using the Drooling Severity Scale and Drooling Frequency Scale. As a result, improvements in the patients' Drooling Severity Scale and Drooling Frequency Scale scores, but no improvements in their visual analog scale scores, were observed after scopolamine butylbromide treatment. These results indicate that at least some schizophrenic patients with clozapine-induced hypersalivation would benefit from scopolamine butylbromide treatment. We conclude that clozapine-induced hypersalivation is one factor of stress to patients. Subjective hypersalivation was not improved, but objective hypersalivation was, by scopolamine butylbromide treatment. However, scopolamine butylbromide and clozapine possess anticholinergic effects so clinicians should closely monitor patients who take scopolamine butylbromide.
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2006
Recent evidence suggests that the AKT1-GSK3beta signalling cascade partially mediates dopamine-de... more Recent evidence suggests that the AKT1-GSK3beta signalling cascade partially mediates dopamine-dependent behaviours. In relation to the pathophysiology of schizophrenia or methamphetamine (Meth) use disorder, AKT1 is a good candidate gene for such conditions. For schizophrenia, positive associations of SNPs and AKT1 haplotypes were reported in US and Japanese samples. To evaluate the association between AKT1 and Meth-use disorder, we conducted a case-control study of Japanese samples (182 patients and 437 controls). A positive association between a SNP and haplotypes was found, and the 'signal' SNP was the same SNP found to be associated with US schizophrenia, but not with Japanese schizophrenia. Our results indicate that AKT1 may play a possible role in the development of Meth-use disorder. Further investigation of these associations, together with evidence from previous animal studies, may open the way to elucidation of the pathophysiology of this condition.
Schizophrenia is a common psychiatric disorder characterized by disturbances of cognition, emotio... more Schizophrenia is a common psychiatric disorder characterized by disturbances of cognition, emotion and social functioning. There are few studies investigating a possible genetic basis for the underlying mechanism of cognitive dysfunctions. A genetic variation in the dysbindin gene (DTNBP1: dystrobrevin binding protein 1), a susceptibility gene for schizophrenia, has been reported to be associated with general cognitive ability and cognitive decline in patients with schizophrenia. Although profound disturbances of memory performance are observed in schizophrenia, only one study has reported a relationship between this gene and spatial working memory in a Caucasian population. We examined a possible association between a protective haplotype of DTNBP1 for developing schizophrenia and memory performance measured by the Wechsler Memory Scale-Revised (WMS-R) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) in 165 healthy volunteers and 70 patients with schizophrenia in a Japanese population. Healthy controls that carry the protective haplotype showed higher performance in several memory domains measured by the WMS-R than those who did not. Genotype effect on memory performance was not observed in patients with schizophrenia. This haplotype did not affect IQ and its sub-scores as measured by the Wechsler Adult Intelligence Scale-Revised in both groups. These data suggest that DTNBP1 may have impact on parts of memory functions.
Microarray studies of schizophrenic brains revealed decreases in the expression of myelin and oli... more Microarray studies of schizophrenic brains revealed decreases in the expression of myelin and oligodendrocyte-related genes. Of these genes, sex-determining region Y-box 10 (SOX10) is a major transcription factor modulating the expression of proteins involved in neurogenesis and myelination. The SOX10 gene is located on chromosome 22q13.1, a region repeatedly reported to show positive signals in linkage studies on schizophrenia. This study was conducted to clarify the exact role of SOX10 in the pathophysiology of schizophrenia. We performed an association analysis of SOX10 in a Japanese population of 915 schizophrenic patients and 927 controls. Genotyping was carried out using polymerase chain reaction restriction fragment length polymorphism. One single nucleotide polymorphism of the SOX10 gene (rs139,887) was selected as a haplotype tag single nucleotide polymorphism using 96 controls. A significant association was observed in the genotype and allelic frequency of this single nucleotide polymorphism between schizophrenic patients and controls (P=0.025 and P=0.009, respectively). Especially, a significant association was found in male patients, but not female patients. We also performed a mutational search of the whole coding region, branch site, and promoter region of SOX10 in 96 schizophrenic patients, but no potential functional polymorphisms were detected. This study suggests that the SOX10 gene is related to the development of schizophrenia in the Japanese population.
We organized a multicenter study of a relatively large sample of 519 patients with bipolar disord... more We organized a multicenter study of a relatively large sample of 519 patients with bipolar disorder (according to DSM-IV criteria) and 588 control subjects matched for gender, age, and ethnicity (Japanese). Genotyping was done by polymerase chain reactionbased restriction ...
Postmortem studies regarding schizophrenia revealed altered expression of genes related to gamma-... more Postmortem studies regarding schizophrenia revealed altered expression of genes related to gamma-amino butyric acid neurotransmission system. One of the most consistent findings is the reduced level of 67 kDa glutamic acid decarboxylase isoform (GAD(67)). Moreover, several studies reported positive associations between the GAD(67) gene (GAD1) and schizophrenia. These reasons, motivated us to carry out replication study regarding association between GAD1 (fourteen tagging SNPs) and schizophrenia in Japanese population (562 schizophrenic patients and 470 controls). However we couldn't confirm significant association that had been previously reported. Considering size of our sample and strategy that corresponds well with the approaches used in gene-based association analysis, our conclusion is that GAD1 does not play a major role in schizophrenia in Japanese population.
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2008
Selective serotonin reuptake inhibitor (SSRI)-induced nausea can be severe enough to lead to earl... more Selective serotonin reuptake inhibitor (SSRI)-induced nausea can be severe enough to lead to early treatment discontinuation. However, it is currently not possible to predict the occurrence of nausea before the initiation of SSRI treatment. In this study, we investigated the effect of genetic polymorphisms in the 5-hydroxytryptamine type 2A, 3A, and 3B (5-HT3B) receptors, 5-HT transporter, and CYP2D6 genes on the incidence of paroxetine-induced nausea. A consecutive series of 72 Japanese patients with depressive or anxiety disorders were treated with paroxetine. Paroxetine-induced nausea was assessed by a pharmacist and was observed in 29.2% of the patients. A significant (nominal p=0.00286) association was found between the incidence of nausea and the -100_-102AAG insertion/deletion polymorphism of the 5-HT3B receptor gene. No significant associations were observed between the other genetic polymorphisms and the incidence of nausea. The -100_-102AAG deletion variant of the 5-HT3B r...
Clinical Psychopharmacology and Neuroscience, 2015
Clozapine has been demonstrated to be useful for treating refractory schizophrenia. However, hype... more Clozapine has been demonstrated to be useful for treating refractory schizophrenia. However, hypersalivation occurs in 31.0- 97.4% of the patients treated with clozapine. Accordingly, some patients who are disturbed by their hypersalivation refuse to continue with clozapine treatment. This study investigated the efficacy of the anticholinergic agent scopolamine butylbromide against clozapine-induced hypersalivation. Five schizophrenia patients were coadministered scopolamine butylbromide (30-60 mg/ day) for 4 weeks. At the baseline and after 4 weeks' treatment, we subjectively evaluated hypersalivation using a visual analog scale and objectively assessed it using the Drooling Severity Scale and Drooling Frequency Scale. As a result, improvements in the patients' Drooling Severity Scale and Drooling Frequency Scale scores, but no improvements in their visual analog scale scores, were observed after scopolamine butylbromide treatment. These results indicate that at least some schizophrenic patients with clozapine-induced hypersalivation would benefit from scopolamine butylbromide treatment. We conclude that clozapine-induced hypersalivation is one factor of stress to patients. Subjective hypersalivation was not improved, but objective hypersalivation was, by scopolamine butylbromide treatment. However, scopolamine butylbromide and clozapine possess anticholinergic effects so clinicians should closely monitor patients who take scopolamine butylbromide.
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2006
Recent evidence suggests that the AKT1-GSK3beta signalling cascade partially mediates dopamine-de... more Recent evidence suggests that the AKT1-GSK3beta signalling cascade partially mediates dopamine-dependent behaviours. In relation to the pathophysiology of schizophrenia or methamphetamine (Meth) use disorder, AKT1 is a good candidate gene for such conditions. For schizophrenia, positive associations of SNPs and AKT1 haplotypes were reported in US and Japanese samples. To evaluate the association between AKT1 and Meth-use disorder, we conducted a case-control study of Japanese samples (182 patients and 437 controls). A positive association between a SNP and haplotypes was found, and the 'signal' SNP was the same SNP found to be associated with US schizophrenia, but not with Japanese schizophrenia. Our results indicate that AKT1 may play a possible role in the development of Meth-use disorder. Further investigation of these associations, together with evidence from previous animal studies, may open the way to elucidation of the pathophysiology of this condition.
Schizophrenia is a common psychiatric disorder characterized by disturbances of cognition, emotio... more Schizophrenia is a common psychiatric disorder characterized by disturbances of cognition, emotion and social functioning. There are few studies investigating a possible genetic basis for the underlying mechanism of cognitive dysfunctions. A genetic variation in the dysbindin gene (DTNBP1: dystrobrevin binding protein 1), a susceptibility gene for schizophrenia, has been reported to be associated with general cognitive ability and cognitive decline in patients with schizophrenia. Although profound disturbances of memory performance are observed in schizophrenia, only one study has reported a relationship between this gene and spatial working memory in a Caucasian population. We examined a possible association between a protective haplotype of DTNBP1 for developing schizophrenia and memory performance measured by the Wechsler Memory Scale-Revised (WMS-R) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) in 165 healthy volunteers and 70 patients with schizophrenia in a Japanese population. Healthy controls that carry the protective haplotype showed higher performance in several memory domains measured by the WMS-R than those who did not. Genotype effect on memory performance was not observed in patients with schizophrenia. This haplotype did not affect IQ and its sub-scores as measured by the Wechsler Adult Intelligence Scale-Revised in both groups. These data suggest that DTNBP1 may have impact on parts of memory functions.
Microarray studies of schizophrenic brains revealed decreases in the expression of myelin and oli... more Microarray studies of schizophrenic brains revealed decreases in the expression of myelin and oligodendrocyte-related genes. Of these genes, sex-determining region Y-box 10 (SOX10) is a major transcription factor modulating the expression of proteins involved in neurogenesis and myelination. The SOX10 gene is located on chromosome 22q13.1, a region repeatedly reported to show positive signals in linkage studies on schizophrenia. This study was conducted to clarify the exact role of SOX10 in the pathophysiology of schizophrenia. We performed an association analysis of SOX10 in a Japanese population of 915 schizophrenic patients and 927 controls. Genotyping was carried out using polymerase chain reaction restriction fragment length polymorphism. One single nucleotide polymorphism of the SOX10 gene (rs139,887) was selected as a haplotype tag single nucleotide polymorphism using 96 controls. A significant association was observed in the genotype and allelic frequency of this single nucleotide polymorphism between schizophrenic patients and controls (P=0.025 and P=0.009, respectively). Especially, a significant association was found in male patients, but not female patients. We also performed a mutational search of the whole coding region, branch site, and promoter region of SOX10 in 96 schizophrenic patients, but no potential functional polymorphisms were detected. This study suggests that the SOX10 gene is related to the development of schizophrenia in the Japanese population.
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