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There is a reciprocal regulation of arginase and nitric oxide synthase (NOS) in L-arginine-metabolizing pathways. Nitric oxide (NO) may be involved in some psychiatric disorders like schizophrenia, depression and bipolar affective disorder (BPAD). To our knowledge, there is no study in the literature in which the role of arginase, an important part of the arginine regulatory system affecting NOS activity, was investigated in BPAD. This study aims to investigate arginase, manganese (Mn) and total nitrite levels (a metabolite of NO) and their relationship to the arginine-NO pathway in patients with BPAD. Arginase activities, Mn and total nitrite levels were measured in plasma from forty-three patients with BPAD (Type one) and thirty-one healthy control subjects. Plasma arginase activities and Mn were found to be significantly lower and total nitrite level higher in patients with BPAD compared with controls. Our results suggest that the arginine-NO pathway is involved in the pathogenesis of BPAD.

Background: There is evidence that oxygen free radicals play an important role in the pathophysiology of many neuropsychiatric disorders. Although it has not been investigated yet, several recent studies proposed that nitric oxide (NO) and other parameters related to oxidative stress may have a pathophysiological role in autism., Methods: We assessed the changes in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and thiobarbituric acid-reactive substances (TBARS) levels in plasma as well as NO levels in red blood cells (RBC) in patients with autism (n=27) compared to age- and sex-matched normal controls (n=30)., Results: In the autistic group, increased RBC NO levels (p<0.0001) and plasma GSH-Px activity (p<0.0001) and unchanged plasma TBARS levels and SOD activity were detected., Conclusions: These findings indicate a possible role of increased oxidative stress and altered enzymatic antioxidants, both of which may be relevant to the pathophysiology of autism.

Several studies indicate that nitric oxide (NO) is involved in the aetiopathogenesis of many neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, Alzheimer's disease, Hungtington disease and stroke. Although it has not been investigated yet, several recent studies proposed that NO may have a pathophysiological role in autism. Adrenomedullin (AM), a recently discovered 52-amino acid peptide hormone, induces vasorelaxation by activating adenylate cyclase and also by stimulating NO release. AM immune reactivity is present in the brain consistent with a role as a neurotransmitter. It has been stated that NO and AM do function in the regulation of many neurodevelopmental processes. We hypothesized that NO and AM activities have been affected in autistic patients and aimed to examine these molecules. Twenty-six autistic patients and 22 healthy control subjects were included in this study. AM and total nitrite (a metabolite of NO) levels have been measured in plasma. The mean values of plasma total nitrite and AM levels in the autistic group were significantly higher than control values, respectively (p < 0.001, p = 0.028). There is no correlation between total nitrite and AM levels (r = 0.11, p = 0.31). Certainly, this subject needs much further research investigating autistic patients in earlier periods of life and with subtypes of the disorder., (Copyright 2002 John Wiley & Sons, Ltd.)

The reciprocal regulation of arginase and nitric oxide synthase (NOS) in L-arginine-metabolizing pathways has been demonstrated. There are various evidences of the role of the nitric oxide (NO) in several neuropsychiatric disorders including schizophrenia. However, there is no study which has investigated the role of arginase as an important part of the arginine regulatory system affecting NOS activity in schizophrenia. This study aims to investigate arginase, manganese (Mn) and total nitrite levels (a metabolite of NO) and their relationship to the arginine-NO pathway in patients with schizophrenia. Arginase activities, Mn and total nitrite levels were measured in plasma from 46 patients with schizophrenia and 32 healthy control subjects. Plasma arginase activities and Mn were found to be significantly lower and total nitrite level higher in patients with schizophrenia compared with controls. Our results suggest that the arginine-NO pathway is involved in the pathogenesis of schizophrenia., (Copyright 2003 S. Karger AG, Basel)

Evidence is accumulating for a possible role of nitric oxide (NO) in schizophrenia. Adrenomedullin (AM) induces vasorelaxation by activating adenylate cyclase and also by stimulating the release of NO. AM immune reactivity is present in the brain consistent with a role as neurotransmitter. We aimed to examine plasma levels of nitrite (a metabolite of NO) and AM in schizophrenic patients. Eighty-two patients with schizophrenia and 21 healthy control subjects were included in this study. DSM-IV diagnosis of chronic schizophrenia was established on the basis of independent structured clinical interviews and review of records by two qualified psychiatrists which included the Brief Psychiatric Rating Scale (BPRS), The Scale for the Assessment of Negative Symptoms (SANS) and The Scale for the Assessment of Positive Symptoms (SAPS). Total nitrite and AM have been studied in plasma. The mean values of plasma nitrite and AM levels in schizophrenic group were significantly higher than control values, respectively (P=0.03, P<0.0001). AM levels of schizophrenic patients were three fold higher than controls. In correlation analyses, there were statistically significant positive correlations between AM level and SAPS-delusion subscale (r=0.27, P=0.04); SAPS-bizarre behavior subscale (r=0.28, P=0.03) and SAPS-total (r=0.36, P=0.005). There is no correlation between total nitrite and AM levels (r=0.11, P=0.31). Both NO and AM may have a pathophysiological role in schizophrenia, and clinically symptomatology and prognosis of schizophrenia. This subject needs further study including treatment response and subtypes of schizophrenia.

Nitric oxide (NO) has been implicated to play a role in the pathogenesis of depressive disorders. Adrenomedullin (AM) induces vasorelaxation by activating adenylate cyclase and also by stimulating the release of NO. AM immune reactivity is present in the brain, consistent with a role as neurotransmitter. Therefore, it is suggested that these two molecules may play a role together in the brain. We aimed to examine AM and NO in bipolar affective disorder (BPAD). Forty-four patients with BPAD and 21 healthy control subjects were included in this study. DSM-IV diagnosis of bipolar affective disorder (type I, manic episodes) was independently established by two psychiatrists and the Turkish version of the Bech-Rafaelson Mania Scale was administered. Also, a semistructured form was used to ascertain several sociodemographic and clinical variables of the patients. AM and NO were studied in plasma. The mean value of plasma NO levels in the BPAD group of 46.58 +/- 13.97 micromol/l was significantly higher than that of controls (31.81 +/- 8.14 micromol/l) (z = -4.15, p = 0.000). Mean plasma AM levels were found to be increased in patients with BPAD (35.13 +/- 5.26 pmol/l) compared to controls (16.22 +/- 3.02 pmol/l) (z = -6.16, p = 0.000). AM levels of BPAD patients were approximately 2-fold higher than controls. AM levels were positively correlated with the duration of hospitalization for the current episode and negatively correlated with the total duration of illness. Both NO and AM may have a pathophysiological role in BPAD (type I, manic episodes) and the clinical symptomatology and prognosis of BPAD., (Copyright 2002 S. Karger AG, Basel)

Evidence is accumulating for a possible role of nitric oxide (NO) in schizophrenia. Adrenomedullin (AM) induces vasorelaxation by activating adenylate cyclase and also by stimulating the release of NO. AM immune reactivity is present in the brain consistent with a role as neurotransmitter. We aimed to examine plasma levels of nitrite (a metabolite of NO) and AM in schizophrenic patients. Eighty-two patients with schizophrenia and 21 healthy control subjects were included in this study. DSM-IV diagnosis of chronic schizophrenia was established on the basis of independent structured clinical interviews and review of records by two qualified psychiatrists which included the Brief Psychiatric Rating Scale (BPRS), The Scale for the Assessment of Negative Symptoms (SANS) and The Scale for the Assessment of Positive Symptoms (SAPS). Total nitrite and AM have been studied in plasma. The mean values of plasma nitrite and AM levels in schizophrenic group were significantly higher than control values, respectively (P=0.03, P<0.0001). AM levels of schizophrenic patients were three fold higher than controls. In correlation analyses, there were statistically significant positive correlations between AM level and SAPS-delusion subscale (r=0.27, P=0.04); SAPS-bizarre behavior subscale (r=0.28, P=0.03) and SAPS-total (r=0.36, P=0.005). There is no correlation between total nitrite and AM levels (r=0.11, P=0.31). Both NO and AM may have a pathophysiological role in schizophrenia, and clinically symptomatology and prognosis of schizophrenia. This subject needs further study including treatment response and subtypes of schizophrenia. [Copyright &y& Elsevier]

Objective: Bipolar affective disorder (BAD) is a common disease. The physiopatholgical factors that cause BAD are not clear. It was recently hypothesized that the disordered oxidative factors have role in the ethiology. Nitric oxide (NO), which is synthesized by nitric oxide synthetase, is found both in central and periferic nervous system. NO acts as an free oxygen radical and a neuro-transmitter. It is estimated that NO has a role in the pathophysiology of many neuropsychiatric disease including bipolar affective disorder. Arginase is mainly located in the liver and cathalizes urea synthesis. This enzyme cathalizes L-arginine which is also used for NO synthesis. Methods: Thirty three patients with BAD and 33 healthy controls were included in this study. Serum NO levels and arginase activity were measured before and 1 month after the therapy in patients. The controls' samples were also measured. NO levels were measured by Griess reaction. Arginase activity was detected using modified Gayer and Dabich methods. Results: Serum NO levels were found 192,2±13,7 μmol/L (mean±SEM) 126,1±6,3 μmol/L before and after the treatment, respectively (p<0.001). The mean NO level was 109,5±6,2 μmol/L in controls, and the difference was statistically not significant when compared to post treatment results (p>0.05). Serum arginase activities were found 17,5±1,8 U/L and 10,3±1,4 U/L before and after the treatment, respectively (p<0.001). Arginase activity was 8,5±1,5 U/L in controls and the difference was not statistically significant when compared to post treatment results (p>0.05). Conclusion: Our results suppport that serum NO and arginase have role in the pathogenesis in the BAD. [ABSTRACT FROM AUTHOR]