Monitoring Homovanillic Acid and Vanillylmandelic Acid in Human Urine by Capillary Electrophoresis with Electrochemical Detection

A simple, rapid and low-cost method of separation and determination of homovanillic acid and vanillylmandelic acid in human urine was developed based on capillary zone electrophoresis / amperometric detection with high sensitivity and good resolution.

Zhichan decoction induces differentiation of dopaminergic neurons in Parkinson's disease rats after neural stem cell transplantation

The goal of this study was to increase the dopamine content and reduce dopaminergic metabolites in the brain of Parkinson’s disease rats. Using high-performance liquid chromatography, we found that dopamine and dopaminergic metabolite（dihydroxyphenylacetic acid and homovanillic acid） content in the midbrain of Parkinson’s disease rats was increased after neural stem cell transplantation ＋ Zhichan decoction, compared with neural stem cell transplantation alone. Our genetic algorithm results show that dihydroxyphenylacetic acid and homovanillic acid levels achieve global optimization. Neural stem cell transplantation ＋ Zhichan decoction increased dihydroxyphenylacetic acid levels up to 10-fold, while transplantation alone resulted in a 3-fold increment. Homovanillic acid levels showed no apparent change. Our experimental findings show that after neural stem cell transplantation in Parkinson’s disease rats, Zhichan decoction can promote differentiation of neural stem cells into dopaminergic neurons.

Effects of Echinacoside on Histio-central Levels of Active Mass in Middle Cerebral Artery Occlusion Rats

Objective To investigate the effects of echinacoside on the extracellular striatal levels of norepinephrine（NE）,dopamine（DA）,homovanillic acid（HVA）,3,4-dihydroxyphenylethanoid acid（DOPAC）,5-hydroxyindoleacetic acid（HIAA）,and 5-hydroxytryptamine（5-HT） in middle cerebral artery occlusion（MCAO rats.Methods The middle cerebral artery was occluded in male Sprague-Dawley rats.Three days later microdialysis probes were placed into the right striatum of MCAO rat brains and the brains were perfused with Ringer＇s solution at a rate of 1.5 μL/min.Cerebral microdialysates were collected every 30 minutes from awake and freely moving rats before assaying for NE,DA,HVA,DOPAC,HIAA,and 5-HT levels by reverse phase HPLC with electrochemistry.Results Three days after MCAO,the extracellular striatal levels of NE,DA,DOPAC,HIAA,HVA,and 5-HT of the MCAO rats increased significantly（at least P0.05 vs.control）.However,simultaneous treatment with echinacoside（30.0 or 15.0 mg/kg） attenuated these increases（at least P0.05 vs.non-treated model rats）.Conclusion These results imply that echinacoside may protect striatal dopa minergic neurons from the injury induced by MCAO and may help prevent and treat cerebral ischemic diseases.

Zhichan powder regulates nigrostriatal dopamine synthesis and metabolism in Parkinson's disease rats

In this study, rat models of Parkinson＇s disease induced by substantia nigra injection of 6-hydroxy-dopamine were intragastrically administered Zhichan powder daily for 50 days. Reverse transcription PCR results showed that tyrosine hydroxylase mRNA expression in the rat substantia nigra was significantly increased, while monoamine oxidase B mRNA expression was significantly decreased in the Zhichan powder group, compared with the model group. In addition, the levels of striatal dopamine and homovanillic acid, the ratio of dopamine to homovanillic acid, and the activity of blood superoxide dismutase were all higher in the Zhichan powder group than in the model group but the content of malondialdehyde in blood was lower. Our experimental findings indicate that Zhichan powder has an antioxidant effect, it can regulate the expression of monoamine oxidase B and tyrosine hydroxylase in the substantia nigra of Parkinson＇s disease rats, and it can facilitate the secretion of striatal dopamine and its metabolite homovanillic acid.

Altered serous levels of monoamine neurotransmitter metabolites in patients with refractory and non-refractory depression

The study examined plasma metabolite changes of monoamine neurotransmitters in patients with treatment-resistant depression （TRD） and non-TRD before and after therapy. All 30 TRD and 30 non-TRD patients met the diagnostic criteria for a depressive episode in accordance with the International Classification of Diseases, Tenth Revision. Before treatment, and at 4, 6, and 8 weeks after treatment, the plasma metabolite products of monoamine neurotransmitters in TRD group, including 5-hydroxyindoleacetic acid, 3-methoxy-4-hydroxyphenyl ethylene glycol and homovanillic acid, were significantly lower than those in the non-TRD group. After two types of anti-depressive therapy with 5-serotonin and norepinephrine reuptake inhibitor, combined with psychotherapy, the Hamilton Depression Rating Scale scores were significantly reduced in both groups of patients, and the serous levels of 5-hydroxyindoleacetic acid and 3-methoxy-4-hydroxyphenyl ethylene glycol were significantly increased. In contrast, the homovanillic acid level exhibited no significant change. The levels of plasma metabolite products of peripheral monoamine neurotransmitters in depressive patients may predict the degree of depression and the therapeutic effects of treatment.

Rapid Determination of Dopamine and Its Metabolites During in vivo Cerebral Microdialysis by Routine High Performance Liquid Chromatography With Electrochemical Detection

To determine dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection. Methods Microdialysis probes were placed into the right striatum of Wistar rat brains and perfused with Ringer＇s solution at a rate of 1.5 pL/min. A reverse phase HPLC with electrochemistry was used to assay DA, DOPAC, and HVA after cerebral microdialysates were collected every 20 minutes from awake and freely moving rats. In order to identify the reliability of this method, its selectivity, linear range, precision and accuracy were tested and the contents of DA, DOPAC, and HVA in rat microdialysates were determined. Results The standard curve was in good linear at the concentration ranging from 74 nmol/L to 1.5 pmol/L for DOPAC （r^2= 0.9996）, from 66 nmol/L to 1.3 gmol/L for DA （r^2=l.0000） and from 69 nmol/L to 1.4 pmol/L for HVA （r^2=0.9992）. The recovery of DOPAC （0.30, 0.77, 1.49 gmol/L）, DA （0,26, 0.69, 1.32 gmol/L）, and HVA （0.27, 0.71, 1.37 gmol/L） was 82.00±1.70%, 104.00±4.00%, 98.70±3.10%; 92.30± 1.50%, 105.30±2.30%, 108.00±2.00%; 80.00±7.80%, 107.69±8.00%, and 108.66±3.10%, respectively at each concentration. Their intra-day RSD was 3.3%, 3.4%, and 2.5%, and inter-day RSD was 4.2%, 2.3%, and 5.6%, respectively. The mean extracellular concentrations of DOPAC, DA, and HVA in rat brain microdialysates were 10.7, 2.4, and 9.2 gmol/L （n=6）, respectively. Conclusion The findings of our study suggested that the simple, accurate and stable method can be applied to basic researches of diseases related to monoamines neurotransmitters by cerebral microdialysis in rats.

Effects of Ningdong granule on DA,DRD2,and HVA in a rat model of Tourette's syndrome

OBJECTIVE:Ningdong granule is a traditional Chinese medicine preparation for the treatment of Tourette's syndrome.METHODS:Sixty-four rats were randomly assigned to a control group and three experimental groups,respectively.Rat models of Tourette's syndrome were established via intraperitoneal injection of apomorphine(Apo).The rats in the experimental groups were subsequently intragastrically injected with haloperidol at 10 mg/kg(haloperidol group),Ningdong granule at 370 mg/kg(NDG group),and normal saline(0.9%) at 10 mL/kg(Apo group),respectively.Rat behaviors were observed and recorded on a daily basis.After 12 w,all rats were sacrificed,and sera and striatal tissues were harvested.Homovanillic acid levels in sera,as well as dopamine and dopamine D2 receptor mRNA expression in the striatum,were measured to determine possible mechanisms of Ningdong granule on the dopamine system in a rat model of Tourette's syndrome.RESULTS:Following intervention,stereotype actions of the Tourette's syndrome rats were significantly inhibited in the haloperidol and NDG groups,respectively(P<0.01).Homovanillic levels were significantly greater in the haloperidol and NDG groups,respectively(P<0.05).In addition,dopamine levels were significantly less in the NDG group(P<0.01),and DRD2 mRNA expression was significantly reduced in the haloperidol and NDG groups,respectively(P<0.05).CONCLUSION:Results demonstrated that Ningdong granule effectively inhibited stereotype actions and Tourette's syndrome symptoms by promoting dopamine metabolism,reducing dopamine levels in the striatum,increasing homovanillic acid content in sera,and reducing mRNA expression of DRD2 in the striatum.

Neuroprotective effects of xanthone extract from Swertia punicea Hemsl against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson's disease

As a widely used traditional Chinese medicine （TCM）, Swertia punicea Hemsl has exhibited effects on anti-hepatitis B virus （HBV）, liver protection, hypoglycemic activity and cholecystitis. In this study, we confirmed that xanthone extract from Swertia punicea Hemsl （XSPH） improved the motor deficit, increased the levels of striatal dopamine （DA） and homovanilic acid （HVA）, and alleviated the loss of tyrosine hydroxylase （TH）-positive neurons located in substantia nigra pars compacta （SNpc） in MPTP-induced mouse model of Parkinson＇s disease （PD）. In conclusion, the present results indicated that XSPH offered neuroprotective effects against the neurotoxicity of MPTP and it might be a potential treatment for PD.