Dopamine In Samples Research Articles

Levels of biogenic amines in lung tissues of patients with non-small cell lung cancer after COVID-19 of various severity

Purpose of the study. Was to analyze levels of biogenic amines (serotonin and its metabolite 5-HIAA, dopamine, norepinephrine and histamine) in lung tissues of patients with lung cancer with previous COVID-19 infection.Patients and methods. The study was carried out on samples of intact lung tissues, tumor tissues and peritumoral lung tissues obtained during open biopsy while performing radical surgery from patients with morphologically verified non-small cell lung cancer (NSCLC), stage I–IIIA (cT1–3NХM0). The main group included 30 NSCLC patients (15 men and 15 women) after severe or moderate to severe COVID-19 who required hospitalization. The control group included 15 men and 15 women with NSCLC after asymptomatic or mild SARS-CoV-2 infection. The mean age of patients was 59.11 ± 2.9 years. Levels of dopamine, norepinephrine, serotonin, 5-hydroxyindoleacetic acid (5-HIAA) and histamine were measured by ELISA (IBL, Germany).Results. All studied lung tissue samples from men and women of the main group, compared to the control group, showed deficiency of catecholamines with their ratio unchanged, and changes in serotonin metabolism to ensure its stable level. Thus, levels of dopamine in samples of patients of the main group were lower on average by 1.3 times, norepinephrine by 1.3–3.3 times, serotonin by 1.6 times, and 5-HIAA by 1.8–4 times. At the same time, sex differences were observed in histamine levels. Regardless of the COVID-19 severity, levels of diamine in women were lower in the resection line tissue by an average of 2.4 times, and in the peritumoral tissue by 1.6 times, compared with men, but there were no sex differences in the tumor tissue. Conclusion. Apparently, changes in the levels of dopamine, norepinephrine, and serotonin in lung tissues could be associated with the severity of SARS-CoV-2 infection. Since dopamine is involved in counteracting the carcinogenic action of the adrenergic system and in the regulation of various immunocompetent cells in the tumor microenvironment, such changes in the biogenic status in the lungs of patients of the main group could lead to a more severe tumor course.

Electrochemical Sensing of Dopamine Using Onion-like Carbons and Their Carbon Nanofiber Composites

This work describes the electrochemical detection of dopamine in samples (pure raw materials as well as pharmaceutical formulation) using onion-like carbon (OLC) and its carbon nanofiber composites (OLC-CNF). The OLC-CNF and precursor materials (polyacrylonitrile (PAN) fiber and OLC-PAN) were synthesized using electrospinning process. The morphologies of the samples were obtained using scanning electron microscopy (SEM) while surface area and porosity were determined using the Brunauer–Emmett–Teller (BET) analysis. OLC gave the best surface area (279 m2 g−1) and highest pore volume (1.2 cm3 g−1). To determine electrochemical sensing properties, the materials were drop-cast on the glassy carbn electrode (GCE). The electron transfer properties decrease as follows: OLC > OLC-PAN > OLC-CNF > PAN, suggesting that OLC is the most conductive materials. The modified GCE were used as sensors for the dopamine using electrochemical techniques such as cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). OLC and OLC-CNF gave comparable electrocatalytic activities in terms of sensitivity and limit of detection (OLC 1.23 μM and sensitivity of 0.74 μA/μM, and OLC-CNF 1.42 μM, 0.31 μA/μM). The high performance of OLC is attributed to its advantageous nanoparticulate nature and high conductivity. Both sensors (OLC and OLC-CNF) could be reliably used in the assay of dopamine raw material and its pharmaceutical formulation, dopamine HCl injection (Rotexmedica®). One of the key fndings here is that the incorporation of the CNF into the OLC does not significantly impact on its inherent tensile strain that defines its electrochemical performance.

Investigation on the co-luminescence effect of europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system and its application

A novel luminescence, enhancement phenomenon in the europium(III)-dopamine-sodium dodecylbenzene sulfonate system was observed when lanthanum(III) was added. Based on this, a sensitive co-luminescence method was established for the determination of dopamine. The luminescence signal for the europium (III)-lanthanum(III)-dopamine-sodium dodecylbenzene sulfonate system was monitored at λ(ex) = 300 nm, λ(em) = 618 nm and pH 8.3. Under optimized conditions, the enhanced luminescence signal responded linearly to the concentration of dopamine in the range 1.0 × 10(-10)-5.0 × 10(-7) mol/L with a correlation coefficient of 0.9993 (n = 11). The detection limit (3σ) was 2.7 × 10(-11) mol/L and the relative standard deviation for 11 parallel measurements of 3.0 × 10(-8) mol/L dopamine was 1.9%. The presented method was successfully applied for the estimation of dopamine in samples of pharmaceutical preparations, human serum and urine. The possible luminescence enhancement mechanism of the system is discussed briefly.

A Selective Voltammetric Method for Detecting Dopamine at Quercetin Modified Electrode Incorporating Graphene

AbstractThe development of a quercetin‐graphene composite‐modified glassy carbon electrode (Qu/GH/GCE) for the selective and sensitive detection of dopamine (DA) is described in this paper. To fabricate the Qu/GH/GCE, graphene (GH) was first coated onto the surface of a glassy carbon electrode (GCE) and then quercetin (Qu) was electrodeposited on the GH matrix. Transmission electron microscopy (TEM) was used to characterize the morphology of the obtained GH and Qu/GH, and the electrochemical properties of the modified electrode were studied using electrochemical techniques. The as‐prepared Qu/GH/GCE occupied a synthetic property between GH and Qu. The common overlapped electrochemical oxidation peaks of DA and AA were completely separated and a remarkable increasing electron‐oxidation current of DA occurred on the Qu/GH/GCE, which enabled the sensitive and selective electrochemical detection of DA in the presence of ascorbic acid (AA) with peak difference of ca. 452 mV between DA and AA. The peak current obtained at 0.174 V (vs. saturated calomel electrode, SCE) from differential pulse voltammetry (DPV) is linearly dependent on the DA concentration in the range from 3.0×10−8 to 4.0×10−4 mol/L with a detection limit of 1.0×10−8 mol/L. Furthermore, the Qu/GH/GCE exhibits good reproducibility and stability, and has been used for the determination of DA in samples of rat’s striatum tissue with satisfactory results.

Detection of dopamine in non-treated urine samples using glassy carbon electrodes modified with PAMAM dendrimer-Pt composites

Composites of hydroxyl-terminated PAMAM dendrimers, generation 4.0 (64 peripheral OH groups) containing Pt nanoparticles were synthesized at different reaction times using a microwave reactor. The synthetic procedure resulted in dendrimer encapsulated nanoparticles of Pt (DENs-Pt) of 1.53 ± 0.17 nm diameter that was calculated from transmission electron microscopy, and the Pt nanoparticles had single crystal plane in (1 1 1) orientation determinate by selective area diffraction. Each composite was electrochemically immobilized on a pre-functionalized glassy carbon (GC) electrode that was incorporated as a flow injection amperometric (FIA) detector, for the selective detection and quantification of dopamine (DA) in untreated urine samples. Comparison of the analytical performance of the novel electrochemical detector revealed that the DENs-Pt modified GC electrode with the composite synthesized for 30 min in the microwave reactor, showed the best response for the detection of DA in samples of non-treated urine, being the detection and quantification limits smaller (19 and 9 ppb, respectively) than those corresponding to the naked a GC electrode (846 and 423 ppb, respectively) using the FIA detector. In addition, it was found that this electroanalytical approach suffers minimal matrix effects that arise in the analysis of DA in untreated samples of urine.

Glassy carbon electrodes modified with composites of starburst-PAMAM dendrimers containing metal nanoparticles for amperometric detection of dopamine in urine

Composites of hydroxyl-terminated PAMAM dendrimers, generation 4.0 (64 peripheral OH groups) containing either Ir, Pt or Rh nanoparticles were synthesized and characterized in solution. Each one of these composites was then immobilized on a glassy carbon electrode (GC) and incorporated as an amperometric detector for dopamine in a high-performance liquid chromatograph (HPLC). Comparison of the analytical performance of the novel electrochemical detectors with a typical UV–vis optical detector for dopamine revealed that the sensitivity of the GC electrode modified with dendrimer-Rh composite is comparable to that of the spectroscopic detector, with a detection limit of 0.15 μM, and is linear up to at least 1.0 mM ( R 2 = 0.998). Furthermore, it was found that the electroanalytical approach suffers minimal matrix effects that arise in the analysis of dopamine in samples of urine.

Electrochemical behavior of a covalently modified glassy carbon electrode with aspartic acid and its use for voltammetric differentiation of dopamine and ascorbic acid

Aspartic acid was covalently grafted on to a glassy carbon electrode (GCE) by amine cation radical formation in the electrooxidation of the amino-containing compound. X-ray photoelectron spectroscopic (XPS) measurement and cyclic voltammetric experiments proved the aspartic acid was immobilized as a monolayer on the GCE. Electron transfer to Fe(CN)6(4-) in solution of different pH was studied by cyclic voltammetry. Changes in solution pH resulted in the variation of the charge state of the terminal group; surface pK(a) values were estimated on the basis of these results. Because of electrostatic interactions between the negatively charged groups on the electrode surface and dopamine (DA) and ascorbic acid (AA), the modified electrode was used for electrochemical differentiation between DA and AA. The peak current for DA at the modified electrode was greatly enhanced and that for AA was significantly reduced, which enabled determination of DA in the presence of AA. The differential pulse voltammetric (DPV) peak current was linearly dependent on DA concentration over the range 1.8 x 10(-6)-4.6 x 10(-4) mol L(-1) with slope (nA micromol(-1) L) and intercept (nA) of 47.6 and 49.2, respectively. The detection limit (3delta) was 1.2 x 10(-6) mol L(-1). The high selectivity and sensitivity for dopamine was attributed to charge discrimination and analyte accumulation. The modified electrode has been used for determination of DA in samples, in the presence of AA, with satisfactory results.

Effects of noradrenaline on rat paratracheal neurones and localization of an endogenous source of noradrenaline.

1. Intracellular recording techniques were used to study the actions of exogenous noradrenaline (NA) on rat paratracheal neurones in situ. The receptor subtypes underlying these actions were investigated by application of selective adrenoceptor antagonists. 2. Application of NA (0.1-10 microM) by superfusion evoked a membrane depolarization in 85% (52 out of 61) of all paratracheal neurones studied. The response consisted of a slow depolarization which was sometimes accompanied by action potential discharge. In 26 out of 31 cells the response was associated with a change in input resistance of the cell membrane. In 22 out of 26 cells there was a 30% increase, whilst in a further 4 cells there was a 15% decrease in input resistance. The amplitude of the NA depolarization was concentration-dependent. 3. The depolarization evoked by NA was reversibly antagonized by prazosin (1 microM) but unaffected by yohimbine (1 microM) or propranolol (1-10 microM). 4. High performance liquid chromatography with electrochemical detection (h.p.l.c.-e.c.d.) was used to assay for NA and dopamine in samples containing mainly paratracheal ganglia and in samples of tracheal smooth muscle with mucosa. NA was present in all samples assayed at a level of 1.6 micrograms NA g-1 and 0.5 microgram NA g-1 wet weight of the two sample types respectively. Dopamine was not detected in any samples of either ganglia or smooth muscle with mucosa. 5. It is concluded that NA-evoked depolarizations of rat paratracheal neurones result from stimulation of alpha 1-adrenoceptors, and that local levels of NA may be sufficiently high to activate these receptors directly.

In vivo release of dopamine during perfusion of neurotensin in substantia nigra of the unrestrained rat

The functional effect of neurotensin on the kinetics of dopamine (DA) release in the substantia nigra of the freely moving rat was investigated. After guide tubes for push-pull perfusion were implanted stereotaxically just above the substantia nigra, endogenous stores of DA in this structure were labelled by micro-injection of 0.02–0.05 μCi of [ 14C]-DA. Then an artificial cerebrospinal fluid (CSF) was perfused within the site at a rate of 20 μl/min at successive 5 min intervals. Neurotensin added to the CSF perfusate in concentrations of 0.05–0.1 μg/μl evoked an immediate, Ca ++ dependent release of DA from sites directly within the substantia nigra or a delayed efflux when the peptide was perfused at the edge of this structure. Neurotensin failed to affect the pattern of release of this monoamine at sites which were not within the substantia nigra. Further, the body temperature of the rat also was not altered by neurotensin at any of the sites of perfusions. A relatively inactive analogue of the peptide, [D-Arg] 9 neurotensin, was essentially without effect on DA activity. In double isotope experiments in which the substantia nigra of the rat was labelled with both [ 3H]-5-HT and [ 14C]-DA, the perfusion with neurotensin failed to affect 5-HT efflux while the release of DA was enhanced. Chromatographic analysis of the metabolites of DA in samples of push-pull perfusates revealed that neurotensin enhanced significantly the level of DOPAC and HVA. Overall, these results demonstrate that in the unrestrained rat neurotensin acts selectively within the substantia nigra to alter the presynaptic, Ca ++ dependent release of DA. It is suggested that the mechanism by which the tri-decapeptide functions within this brainstem structure is through its modulation of nigral dopaminergic neurons.