Simultaneous Measurement Of Dopamine Research Articles

Simultaneous voltammetry detection of dopamine and uric acid in human serum and urine with a poly(procaterol hydrochloride) modified glassy carbon electrode

In the present study, procaterol hydrochloride (ProH) was successfully electropolymerized onto a glass carbon electrode (GCE) with simply cyclic voltammetry scans to construct a poly(procaterol hydrochloride) (p-ProH) membrane modified electrode. Compared with the bare GCE, much higher oxidation peak current responses and better peak potentials separation could be obtained for the simultaneous oxidation of dopamine (DA) and uric acid (UA), owning to the excellent electrocatalytic ability of the p-ProH membrane. And it's based on that a square wave voltammetry (SWV) method was developed to selective and simultaneous measurement of DA and UA. Under the optimum conditions, the linear dependence of oxidation peak current on analyte concentrations were found to be 1.0–100 μmol/L and 2–100 μmol/L, giving detection limits of 0.3 μmol/L and 0.5 μmol/L for DA and UA, separately. The as prepared modified electrode shows simplicity in construction with the merits of good reproducibility, high stability, passable selectivity and nice sensitivity. Finally, the proposed p-ProH membrane modified electrode was successfully devoted to the detection of DA and UA in biological fluids such as human serum and urine with acceptable results.

A novel electrochemical sensor based on FeS anchored reduced graphene oxide nanosheets for simultaneous determination of dopamine and acetaminophen

In this paper, FeS nanoparticles anchored on reduced graphene oxide (rGO) nanosheets are synthesized via a facile direct-precipitation method. For the first time, a novel electrochemical sensor is developed based on FeS/rGO nanosheets modified glassy carbon electrode (GCE). It has been proved that the resultant FeS/rGO/GCE sensor is very suitable for the individual and simultaneous measurement of dopamine (DA) and acetaminophen (AC) and delivers excellent anti-interference ability to ascorbic acid (AA) and uric acid (UA). Under optimum conditions with differential pulse voltammetry method, a broad linear response versus the concentrations of DA and AC has been observed in the ranges of 2.0 to 250.0μM and 5.0 to 300.0μM, respectively. The detection limits for DA and AC are 0.098μM and 0.18μM, respectively. Furthermore, the as-obtained sensor has been successfully utilized in real samples and satisfactory results have been achieved. Consequently, by virtue of its outstanding electrocatalytic activity, excellent sensitivity, and long time stability, the as-obtained FeS/rGO modified electrode can be considered as a new promising DA and AC sensor.

A novel electroanalytical method for simultaneous detection of two neurotransmitter dopamine and serotonin in human serum

BackgroundSimultaneous measurement of dopamine and serotonin levels is of greater value because of their coexistence in biological systems. These facts have encouraged chemists to develop faster, simpler, and more sensitive techniques to meet the various demands and many works have been published describing the measurement of serum dopamine and serotonin concentrations using chemically modified electrodes. New methodElectrochemical techniques based on various chemically modified electrodes have been widely explored for the single determination of dopamine and serotonin in vivo or in vitro. To the best of our knowledge, there are only limit reports on the electrochemical determination of dopamine and serotonin using mesoporous materials. On the other hand, simultaneous measurement of dopamine and serotonin concentrations on the basis of silica based mesoporous materials has not been reported. ResultsIn the present work, the development an effective electroanalytical method for the simultaneous determination of dopamine and serotonin using cyclic and differential pulse voltammetry on the mobile crystalline material-41 functionalized by n-aminopropyl is described. Mobile crystalline material-41 functionalized by n-aminopropyl, a kind of mesoporous silica, was synthesized and then used to prepare an electrochemical device for simultaneous determination of dopamine and serotonin. A validated differential pulse voltammetry procedure was described to assay two neurotransmitters separately or combined in human serum. Comparison with existing methodThe prepared sensor shows voltammetric responses with high sensitivity for dopamine and serotonin in optimal conditions, which makes it very suitable for simultaneous determination of these compounds.

Characterization of interactions between phencyclidine and amphetamine in rodent prefrontal cortex and striatum: Implications in NMDA/glycine-site-mediated dopaminergic dysregulation and dopamine transporter function

N-Methyl-d-aspartate (NMDA) antagonists induced behavioral and neurochemical changes in rodents that serve as animal models of schizophrenia. Chronic phencyclidine (PCP, 15mg/(kgday) for 3 weeks via Alzet osmotic pump) administration enhances the amphetamine (AMPH)-induced dopamine (DA) efflux in prefrontal cortex (PFC), similar to that observed in schizophrenia. NMDA/glycine-site agonists, such as glycine (GLY), administered via dietary supplementation, reverse the enhanced effect. The present study investigated mechanisms of glycine-induced reversal of PCP-induced stimulation of AMPH-induced DA release, using simultaneous measurement of DA and AMPH in brain microdialysate, as well as peripheral and tissue AMPH levels. PCP treatment, by itself, increased peripheral and central AMPH levels, presumably via interaction with hepatic enzymes (e.g. cytochrome P450 CYP2C11). GLY (16% diet) had no effect on peripheral AMPH levels in the presence of PCP. Nevertheless, GLY significantly reduced extracellular/tissue AMPH ratios in both PFC and striatum (STR), especially following PCP administration, suggesting a feedback mediated effect on the dopamine transporter. GLY also inhibited acute AMPH (5mg/kg)-induced DA release in PFC, but not STR. These findings suggest that GLY may modulate DA release in brain by producing feedback regulation of dopamine transporter function, possibly via potentiation of NMDA-stimulated GABA release and presynaptic GABAB receptor activation. The present studies also demonstrate pharmacokinetic interaction between AMPH and PCP, which may be of both clinical and research relevance.

Simultaneous measurement of dopamine and ascorbate at their physiological levels using voltammetric microprobe based on overoxidized poly(1,2-phenylenediamine)-coated carbon fiber.

Overoxidized poly-(1,2-phenylenediamine) (OPPD)-coated carbon fiber microelectrodes (CFMEs) exhibit, in combination with square-wave voltammetry (SWV) detection mode, the attractive ability to simultaneously measure low nM dopamine (DA) and mM ascorbate (AA) in a pH 7.4 medium. The PPD polymer film is electrodeposited onto a carbon fiber at a constant potential of 0.8 V versus Ag/AgCl using a solution containing sodium dodecylsulfate as the dopant. After overoxidation using cyclic voltammetry (CV) in the potential range from 0 to 2.2 V at a scan rate of 10 V/s, the resulting OPPD-CFME displays a high SWV current response to cationic DA at approximately 0.2 V and has a favorably low response to anionic AA at approximately 0.0 V vs Ag/AgCl. The preparation of the new OPPD-sensing film has been carefully studied and optimized. The OPPD properties and behavior were characterized using CV and SWV under various conditions and are discussed with respect to DA and AA detection. The linear calibration range for DA in the presence of 0.3 mM AA is 50 nM to 10 microM, with a correlation coefficient of 0.998 and a detection limit of 10 nM using 45-s accumulation. The detection limit for DA in the absence of AA was estimated to be 2 nM (S/N = 3). The linear range for AA in the presence of 100 nM DA is 0.2-2 mM, with a correlation coefficient of 0.999 and a detection limit of 80 microM. The reproducibilities of SWV measurements at OPPD-CFCMEs are 1.6% and 2.5% for 100 nM DA and 0.3 mM AA, respectively. Potential interfering agents, such as 3,4-dihydroxyphenylacetic acid, uric acid, oxalate, human serum proteins, and glucose, at their physiologically relevant or higher concentrations did not have any effect. These favorable features offer great promise for in vitro and in vivo application of the proposed OPPD-coated microprobe.

Simultaneous measurement of dopamine, serotonin, their metabolites and tryptophan in mouse brain homogenates by high-performance liquid chromatography with dual coulometric detection.

A new rapid and sensitive high-performance liquid chromatography (HPLC) method for the simultaneous determination of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine, 5-hydroxytryptamine (serotonin), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and tryptophan has been developed and applied to mouse frontal cortex, caudate nucleus and dorsal raphe assays. A dual coulometric detector was used with detection at +0.25 and +0.55 V, which allowed the determination of tryptophan. Detection limits for all compounds (0.8-9.0 pg per injection, depending on the compounds) were useful for this application. Owing to great sensitivity of the method, the brain tissue samples can be very small, less than 2 mg. Linearity of standards was excellent (r > 0.999 in all cases). Intraday and interday precisions for samples analytes were generally acceptable (intraday assay CV < 8.7% and interday assay CV < 7.0% except for DOPAC and 5-HIAA, which was 11.4% for the low concentrations). Average recoveries of standard additions to sample analytes were > 90%. Attention was paid to stability of standard and sample analytes when stored at +4 degrees C or at -70 degrees C with two different homogenizing agents (0.1 M HClO4 with 10(-7) M ascorbic acid and 0.05 M HClO4 without ascorbic acid). This simple, rapid and efficient method can be used as a basic research tool for modification of brain neurotransmitters in experimental pharmacological protocols for following psychotropic drug treatments in animals.

Simultaneous measurement of dopamine, serotonin, their metabolites and tryptophan in mouse brain homogenates by high‐performance liquid chromatography with dual coulometric detection

A new rapid and sensitive high-performance liquid chromatography (HPLC) method for the simultaneous determination of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine, 5-hydroxytryptamine (serotonin), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and tryptophan has been developed and applied to mouse frontal cortex, caudate nucleus and dorsal raphe assays. A dual coulometric detector was used with detection at +0.25 and +0.55 V, which allowed the determination of tryptophan. Detection limits for all compounds (0.8–9.0 pg per injection, depending on the compounds) were useful for this application. Owing to great sensitivity of the method, the brain tissue samples can be very small, less than 2 mg. Linearity of standards was excellent (r > 0.999 in all cases). Intraday and interday precisions for samples analytes were generally acceptable (intraday assay CV < 8.7% and interday assay CV < 7.0% except for DOPAC and 5-HIAA, which was 11.4% for the low concentrations). Average recoveries of standard additions to sample analytes were >90%. Attention was paid to stability of standard and sample analytes when stored at +4°C or at −70°C with two different homogenizing agents (0.1 M HClO4 with 10−7 M ascorbic acid and 0.05 M HClO4 without ascorbic acid). This simple, rapid and efficient method can be used as a basic research tool for modification of brain neurotransmitters in experimental pharmacological protocols for following psychotropic drug treatments in animals. Copyright © 1999 John Wiley & Sons, Ltd.

Dopaminergic regulation of the serotonergic raphe-striatal pathway: microdialysis studies in freely moving rats

Morphological evidence demonstrates the existence of dopaminergic afferent pathways and dopamine (DA)-containing neurons in the dorsal raphe nucleus (DRN). In a recent report, a DA D2-like receptor-mediated regulation of serotonin (5-HT) extracellular concentration in DRN has been found. Given the existence of somatodendritic 5-HT1A autoreceptors in the DRN, changes of the extracellular concentration of 5-HT in the vicinity of cell bodies and dendrites may be relevant for the control of the activity of ascending serotonergic pathways. In the present brain microdialysis study we have used a chromatographic method (HPLC) enabling the simultaneous measurement of DA, 5-HT, and their main metabolites dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA). The presence of a neuronal pool of DA within the DRN was revealed by the local infusion of amphetamine (10 microM), which significantly increased the extracellular concentration of both amines. The local striatal infusion (10 microM) of the selective DA D1-like agonist SKF-38393, the selective DA D2-like agonist quinpirole (LY 171,555), or the nonselective DA agonist apomorphine markedly decreased DA and DOPAC extracellular concentrations and failed to modify 5-HT or 5-HIAA in the striatum, indicating the lack of terminal (striatal) control of 5-HT release by dopaminergic transmission. In contrast, the systemic administration of apomorphine (2.8 mumol/kg, s.c.) significantly increased the extracellular concentration of 5-HT in the DRN and decreased it in the striatum. The reduction of striatal 5-HT extracellular concentration was prevented by the previous administration of the selective 5-HT1A receptor antagonist WAY 100135 (17.6 mumol/kg, s.c.), which by itself did not change extracellular 5-HT in striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous measurement of dopamine and its metabolites, 5-hydroxytryptamine, 5-hydroxyindoleacetic acid and tryptophan in brain tissue using liquid chromatography and electrochemical detection

An assay has been developed for brain tryptophan using reverse-phase liquid chromatography with electrochemical detection. The method simultaneously assays dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), as well as 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). The method does not require elution from ion exchange resins. After deproteinization and centrifugation samples are injected directly onto the chromatographic column. It was found that small changes in mobile phase pH markedly influenced the retention time of tryptophan while elution of the indoleamines and catecholamines did not change. The assay of these endogenous compounds in a single injection proved not only expedient but inexpensive. Values obtained using alumina and ion exchange resins yielded comparable values.

Simultaneous radioenzymatic assay of dopamine and dihydroxyphenylacetic acid: An index of in vivo dopamine release

The relative brain tissue concentrations of dopamine (DA) and its deaminated metabolite, dihydroxyphenylacetic acid (DOPAC), appears to be a reliable index of the functional activity of dopaminergic neurons. In order to apply this approach to the assessment of dopaminergic neuronal activity in small regions of brain, we have developed a sensitive radioenzymatic assay for simultaneous measurement of DA and DOPAC. The sensitivity of the assay for DA is approximately 10 pg and for DOPAC 100 pg. In addition, the assay is highly specific, simple, and relatively inexpensive. The concurrent estimation of tissue DA and DOPAC concentrations seems to be a reliable means of evaluating the rate of DA turnover or release in behavioral, electrical stimulation, and certain drug paradigms. However, the release or turnover of DA as induced by d-amphetamine (and perhaps other indirectly-acting dopaminemimetic drugs) cannot be meaningfully assessed by measurement of DA and DOPAC alone.