GABA concentration in schizophrenia patients and the effects of antipsychotic medication: a proton magnetic resonance spectroscopy study.

Gamma-amino butyric acid (GABA) is thought to play a role in the pathophysiology of schizophrenia. High magnetic field proton magnetic resonance spectroscopy ((1)H-MRS) provides a reliable measurement of GABA in specific regions of the brain. This study measured GABA concentration in the anterior cingulate cortex (ACC) and in the left basal ganglia (ltBG) in 38 patients with chronic schizophrenia and 29 healthy control subjects. There was no significant difference in GABA concentration between the schizophrenia patients and the healthy controls in either the ACC (1.36+/-0.45 mmol/l in schizophrenia patients and 1.52+/-0.54 mmol/l in control subjects) or the ltBG (1.13+/-0.26 mmol/l in schizophrenia patients and 1.18+/-0.20 mmol/l in control subjects). Among the right handed schizophrenia patients, the GABA concentration in the ltBG was significantly higher in patients taking typical antipsychotics (1.25+/-0.24 mmol/l) than in those taking atypical antipsychotics (1.03+/-0.24 mmol/l, p=0.026). In the ACC, the GABA concentration was negatively correlated with the dose of the antipsychotics (rs=-0.347, p=0.035). In the ltBG, the GABA concentration was positively correlated with the dose of the anticholinergics (rs=0.403, p=0.015). To the best of our knowledge, this is the first study to have directly measured GABA concentrations in schizophrenia patients using (1)H-MRS. Our results suggest that there are no differences in GABA concentrations in the ACC or the ltBG of schizophrenia patients compared to healthy controls. Antipsychotic medication may cause changes in GABA concentration, and atypical and typical antipsychotics may have differing effects. It is possible that medication effects conceal inherent differences in GABA concentrations between schizophrenia patients and healthy controls.

Metabolite changes and gender differences in schizophrenia using 3-Tesla proton magnetic resonance spectroscopy (1H-MRS).

A change in the glutamatergic system is thought to play an important role in the pathophysiology of schizophrenia. The aim of this study was to investigate the changes in metabolites, including glutamate (Glu), in the anterior cingulate cortex (ACC) and the left basal ganglia (ltBG) of patients with chronic schizophrenia using proton magnetic resonance spectroscopy ((1)H-MRS). In addition, since gender differences in this illness were known, we examined the effects of gender on these metabolites. The (1)H-MRS was performed on the ACC and ltBG of 30 patients with schizophrenia and 25 healthy individuals who acted as the control group. The levels of Glu, glutamine (Gln), creatine plus phosphocreatine (Cre), myo-inositol (mI), N-acetylaspartate (NAA), and choline-containing compounds (Cho) were measured. Two-way analysis of variance revealed that the illness significantly affected the levels of Glu and mI in the ACC; both metabolites were lower in the patients with schizophrenia as compared to the control subjects. The results also revealed that gender significantly affected the level of Gln in the ACC and the levels of Cre and NAA in the ltBG; the level of Gln in the ACC were higher in male subjects versus female subjects, whereas Cre and NAA levels in the ltBG were lower in male subjects as compared to female subjects. These results confirmed a change in the glutamatergic system and suggested an involvement of mI in the pathophysiology of schizophrenia.

FKBP5, SERT and COMT mRNA expressions in the peripheral leukocytes during menstruation cycle in healthy reproductive females.

There have been several evidences that the mRNA expressions in the peripheral leukocytes may indicate not only physical but also psychological states. The purpose of this study is whether the mRNA expressional changes in the leukocytes are related to the mental states across the menstrual cycle in reproductive healthy female subjects. Thirty-eight female subjects (22.4+/-1.4 year-old) were participated in this study at three menstruation cycle periods (menstrual, follicular and luteal phase). The FKBP5 (FK506-binding protein gene), SERT (serotonin transporter gene) and COMT (catechol-o-methyltransferase gene) mRNA expressions in the leukocytes were determined with hormonal data. The psychological changes were assessed with self-rating hospital anxiety and depression scale (HADS). Only one thirds of subjects (n=12) had regular menstrual cycles during the experiment. So we analyzed the data from these 12 subjects. The anxiety score of each subject was changed across the menstrual cycle (Friedman test: P<0.05). The FKBP5 mRNA expression was significantly lower in the follicular phase than in the other phases but no changes were seen in either SERT or COMT mRNA expressions among the phases. In conclusion, there are differences of HADS anxiety score and FKBP5 mRNA expression in the leukocytes across the menstrual cycle but there is no correlation between anxiety scores and FKBP5 mRNA.

Subjective and objective quality of life, levels of life skills, and their clinical determinants in outpatients with schizophrenia.

The purpose of the present study is to investigate the relationships among subjective and objective quality of life (QOL), and levels of life skills, and their clinical determinants in outpatients with schizophrenia by using schizophrenia disease-specific QOL measures. Data collected from 64 outpatients were analyzed. Subjective QOL was measured with the Schizophrenia Quality of Life Scale (SQLS) and objective QOL with the Quality of Life Scale (QLS). Patients' family members completed the Life Skills Profile (LSP). Clinical symptoms were also assessed with several scales including the Brief Psychiatric Rating Scale (BPRS) and the Calgary Depression Scale for Schizophrenia (CDSS). Only the motivation/energy scale, but not the other scales of the SQLS, correlated with the QLS. The LSP rated by the family showed significant correlations with both the SQLS and the QLS. The CDSS score predicted each scale of the SQLS, and the BPRS negative symptoms score predicted the QLS. The LSP was predicted by the BPRS negative symptoms score and the CDSS score independently. These results indicate that the patient's QOL could be predicted by the life skills measured by a family member and suggest that active treatment for depressive and negative symptoms might be recommended to improve the patient's QOL and life skills.

Lithium effects on brain glutamatergic and GABAergic systems of healthy volunteers as measured by proton magnetic resonance spectroscopy.

Lithium is a first-line medicinal treatment for acute bipolar disorder and is also used prophylactically in manic depressive illnesses; however, its mechanism of action is still largely unknown. Animal and human studies have suggested that lithium modulates glutamatergic and GABAergic neurotransmissions. The aim of this study is to investigate the effects of lithium on brain glutamate (Glu), glutamine (Gln), and gamma-aminobutyric acid (GABA) levels in healthy individuals using proton magnetic resonance spectroscopy (1H-MRS). In vivo 3 Tesla 1H-MRS was performed on the anterior cingulate cortex and bilateral basal ganglia initially and after two weeks of lithium administration on 8 healthy male subjects who had a mean age of 34.9 years. After two weeks of lithium administration, Gln significantly decreased in the left basal ganglia and showed a decreasing trend in the right basal ganglia. Additionally, Glu+Gln (Glx) significantly decreased in the right basal ganglia and showed a decreasing trend in the left basal ganglia. Glu did not significantly change in any of the three tested areas, and GABA exhibited no significant change after the lithium administration when measured in the anterior cingulate cortex and left basal ganglia. This study is the first to demonstrate that subchronic lithium treatment decreases Gln and Glx levels in the bilateral basal ganglia of healthy individuals. Our finding might suggest that the decrease of Glx levels is associated with the pharmacological actions of subchronic lithium treatment.

Activation of the prefrontal cortex during the Trail-Making Test detected with multichannel near-infrared spectroscopy.

The Trail-Making Test (TMT) is a neuropsychological test for evaluating executive function, and the TMT Part B reflects more complex cognitive processes including cognitive set shifting. The prefrontal cortex (PFC) is thought to be involved in these cognitive processes. The purpose of the present paper was to investigate PFC activation during performance of the TMT Part A and Part B using multichannel near-infrared spectroscopy (NIRS). Subjects were 41 healthy right-handed volunteers. The hemodynamic changes in the PFC during the TMT were measured on a 22-channel NIRS machine. The subjects had a greater increase of oxygenated hemoglobin ([oxyHb]) during the TMT Part B than during Part A in the PFC. Twenty-seven out of the 41 subjects had a bilateral increase of [oxyHb] in the PFC during Part B according to laterality index. NIRS detected activation in the PFC during the performance of the TMT Part B and this PFC activation may reflect executive functions including cognitive set shifting involved in the TMT Part B.

Association between PNPO and schizophrenia in the Japanese population.

Accumulating evidence suggests that both homocysteine metabolism and monoaminergic neurotransmitter systems are important in schizophrenia pathology. We hypothesized that the gene PNPO (pyridoxine 5'-phosphatase oxidase gene) might be a candidate for susceptibility to schizophrenia because PNPO encodes pyridoxamine 5'-phosphate oxidase (EC 1.4.3.5), a rate-limiting enzyme in pyridoxal 5'-phosphate (PLP, vitamin B(6)) synthesis. PLP is a metabolically-active form of vitamin B(6) and thus, is required as a co-factor for enzymes involved in both homocysteine metabolism and synthesis of neurotransmitters such as catecholamine. We examined 8 single nucleotide polymorphisms (SNPs) in PNPO and its 5'-flanking regions in 359 schizophrenia patients and 582 control subjects. Four marker regions of PNPO showed significant levels of allelic associations with schizophrenia (the highest was rs2325751, P=0.004). In addition, the haplotype case-control study revealed a significant association (permutation P<0.00001) between PNPO and schizophrenia. These findings suggest that variations in PNPO may contribute to overall genetic risk for schizophrenia in the Japanese population.

Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism in schizophrenia is associated with age at onset and symptoms.

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor that promotes several functions of neurons and modulates neurotransmissions. It has been reported that there are alterations of BDNF levels in schizophrenic brains and that BDNF gene expressional changes would be responsible for the etiology of schizophrenia. Recent studies have shown that a variation of BDNF gene (Val66Met polymorphism) affects the function of neurons, and is associated with several neurological and psychiatrical disorders. We investigated the relationship between BDNF Val66Met polymorphism and the onset age as well as levels of clinical symptoms in 159 of chronic schizophrenia in-patients diagnosed by DSM-IV. The mean onset ages were 27.5+/-9.5 for BDNF Val/Val, 25.5+/-7.4 for BDNF Val/Met and 22.9+/-6.0 for BDNF Met/Met and this polymorphism was significantly associated with age at onset (P=0.023). The mean Brief Psychiatric Rating Scale scores (BPRS) were significantly different among those three groups (P=0.003). No significant differences were demonstrated comparing the BDNF genotype distributions of positive and negative family history (P=0.21). Our investigation indicates that the BDNF gene Val66Met polymorphism is related to the onset age of schizophrenia and the levels of clinical symptoms that remain after long-term antipsychotic treatment.

Hemodynamic changes in the prefrontal cortex during mental works as measured by multi channel near-infrared spectroscopy (NIRS).

To investigate the brain activation in the prefrontal cortex (PFC) during mental works, we examined blood oxygenation changes of healthy subjects by using multi channel near infrared spectropcopy (NIRS). It was directly confirmed that the PFC was activated during mental tasks in vivo and it was suggested that distribution of the activation in the PFC is different among healthy individuals.

Presenile dementia mimicking Pick's disease: an autopsy case of localized amygdala degeneration with character change and emotional disorder.

This report concerns an autopsy case showing localized amygdala degeneration. The patient was a Japanese single woman without hereditary burden who was 58 years old at the time of death. At the age of 55 years, the patient began to feel anxiety, agitation and depressive in mood. At age 58 years, she developed marked character changes and emotional disorders, although disorientation and memory disturbance were slight. We suspected her disease was a variant of presenile dementia, especially Pick's disease, and some neuroradiological examinations disclosed bilateral temporal involvements. We could not make a definitive diagnosis from the clinical findings. She choked to death 3 years after the disease onset. From the neuropathological examinations, the known neurodegenerative diseases causing dementia, including Pick's disease, were excluded and we diagnosed our case as having localized amygdala degeneration. Localized amygdala degeneration itself is very rare. Moreover, in this case, the amygdala degeneration was presumed to be idiopathic, without any apparent cause. To our knowledge, this is the first case of idiopathic localized amygdala degeneration. This case indicates that localized amygdala degeneration can cause presenile dementia, and that character changes and emotional disorders are predominant over memory disturbance and/or disorientation.