Plasma nitrate levels in deficit versus non-deficit forms of schizophrenia

Plasma nitrate levels in deficit versus non-deficit forms of schizophrenia

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J Psychiatry Neurosci 2003;28(4):288-92

Suzuki, Miyaoka — Department of Psychiatry, Kitasato University School of Medicine, Sagamihara, Kanagawa; Nakaki —
Department of Pharmacology, Teikyo University School of Medicine, Tokyo; Nakamura — Department of Neuropsychiatry,
Keio University School of Medicine, Shinjuku, Tokyo, Japan.

Abstract

Objective: To determine whether nitric oxide production levels differ in patients with deficit and nondeficit forms of schizophrenia.

Methods: We investigated plasma nitrate levels, an index of in vivo nitric oxide production, in patients with deficit syndrome (n = 11) and non-deficit syndrome (n = 14) and healthy controls (n = 12) with a combination of high-performance liquid chromatography and the Griess reaction.

Results: There was no difference found in mean plasma nitrite levels, but plasma nitrate levels
of patients with deficit syndrome were significantly lower than those with non-deficit syndrome (28.0 [SEM 2.5] μmol/L v. 44.2 [SEM 5.5] μmol/L, p < 0.05). Conclusions: A decline in nitric oxide production may be involved in primary negative symptoms in schizophrenia.

Résumé

Objectif : Déterminer si les taux de production de monoxyde d’azote des patients aux prises avec une forme de schizophrénie s’accompagnant d’un déficit sont différents de ceux des patients souffrant de
schizophrénie sans déficit.

Méthodes : Nous avons examiné les concentrations plasmatiques de nitrate, indice de la production in vivo de monoxyde d’azote, chez des patients atteints d’un syndrome avec déficit (n = 11), chez des patients atteints d’un syndrome sans déficit (n = 14) et chez des témoins en bonne santé (n = 12), au moyen de la chromatographie en phase liquide à haut rendement et de la réaction de Griess.

Résultats : On n’a pas observé de différence au chapitre des concentrations plasmatiques moyennes de nitrite, mais les concentrations plasmatiques de nitrate des patients aux prises avec un syndrome avec déficit étaient très inférieures à celles des patients atteints d’un syndrome sans déficit (28,0 [ETM 2,5] μmol/L c. 44,2 [ETM 5,5] μmol/L, p < 0,05). Conclusions : Une diminution de la production de monoxyde d’azote pourrait contribuer aux principaux symptômes négatifs de la schizophrénie.


Medical subject headings: nitric oxide; nitric-oxide synthase; schizophrenia; signs and symptoms.

Submitted Aug. 28, 2002; Revised Dec. 18, 2002; Accepted Jan. 20, 2003

Acknowledgements: We thank Dr. Gohei Yagi and Dr. Masahiro Asai for their introduction of patients and useful discussions.
This study was supported by a Grant-in-Aid for Scientific Research (C) (No. 13671031) from the Japanese Ministry of Education, Culture, Sports, Science and Technology.

Competing interests: None declared for Dr. Nakamura. Dr. Suzuki has received speaker fees from Eisai Pharmaceutical Co. Dr. Nakaki has received speaker fees from Chugai Pharmaceutical Co. Dr. Miyaoka has received speaker fees from Sankyo Pharmaceutical Co., Sumitomo Pharmaceutical Co. and Fujisawa Pharmaceutical Co.

Correspondence to: Dr. Eiji Suzuki, Department of Psychiatry, Kitasato University School of Medicine, 2-1-1 Asamizodai, Sagamihara, Kanagawa, 228-8520, Japan; fax 81 42 765 3570; e-suzuki@kitasato-u.ac.jp