Study Of Plasma Nitric Oxide Concentrations And Nitric Oxide Synthase Gene Polymorphisms In Depressed Patients

ObjectsTo analyze the alterlation of plasma nitric oxide (NO) concentrationsin depressed patients, and to investigate whether there is an associationbetween endothelial nitric oxide synthase (eNOS) gene G894T functionalpolymorphism or neuronal nitric oxide synthase (nNOS) gene C276Tpolymorphism and plasma NO concentrations and antidepressant effectin depressed patients.MethodsPlasma NO concentrations were measured in 70 acute-episode ChineseHan depressed patients before and after antidepressant treatment and 77normal controls. The 17-item Hamilton Depression Rating Scale (HAMD)was used to evaluate clinical depression symptom. The HAMD reductionratio was used to evaluate the antidepressant effect. Genotyping wasperformed using PCR-RFLP techniques both in patients and normalcontrols.Results1. The plasma NO concentrations in acute episode untreated depressedpatients (76.8±31.6μmol/L) were significantly higher than that in thepatients after 8-weeks antidepressant treatment (66.9±25.7μmol/L, P=0.044) and normal controls (64.2±33.3μmol/L, P=0.02). There was nosignificant difference between the plasma NO concentrations in treatedpatients and normal controls (P=0.588).2. The plasma NO concentrations in untreated patients weresignificantly positively associated with baseline HAMD scores (24.3±4.3)(r=0.311, P=0.009).3. Neither genotype (P＞0.05) nor allelic frequencies (P＞0.05) showedsignificant difference between patients and normal contrals for eNOSgene G894T polymorphism or nNOS gene C276T polymorphism.Furthermore, genotypes of eNOS were not associated with plasma NOconcentrations (P＞0.05) and HAMD scores (P＞0.05).ConclusionThese data provide a possibility that plasma NO concentrations arelikely to be indicator for severity of the clinical symptoms in depressendpatients. The eNOS gene G894T polymorphism and nNOS gene C276Tpolymorphism are unlikely to play important roles on plasma NOconcentrations, the susceptibility to depression and antidepressant effect.