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We constructed two-dimensional NiCo-metal–organic-framework (NiCo-MOF) nanosheets based on a facile protocol and then characterized them using multiple approaches (X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission-scanning electron microscopy (FE-SEM), and N2 adsorption/desorption isotherms techniques). As a sensitive electroactive material, the as-fabricated bimetallic NiCo-MOF nanosheets were employed to modify a screen-printed graphite electrode surface (NiCo-MOF/SPGE) for epinine electro-oxidation. According to the findings, there was a great improvement in the current responses of the epinine because of the appreciable electron transfer reaction and catalytic performance of the as-produced NiCo-MOF nanosheets. Differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry were utilized to analyze the electrochemical activity of the epinine on the NiCo-MOF/SPGE. A linear calibration plot was obtained in the broad concentration range (0.07–335.0 µM) with a high sensitivity (0.1173 µA/µM) and a commendable correlation coefficient (0.9997). The limit of detection (S/N = 3) was estimated at 0.02 µM for the epinine. According to findings from DPV, the electrochemical sensor of the NiCo-MOF/SPGE could co-detect epinine and venlafaxine. The repeatability, reproducibility and stability of the NiCo-metal–organic-framework-nanosheets-modified electrode were investigated, and the relative standard deviations obtained indicated that the NiCo-MOF/SPGE had superior repeatability, reproducibility and stability. The as-constructed sensor was successfully applicable in sensing the study analytes in real specimens. [ABSTRACT FROM AUTHOR]

We constructed two-dimensional NiCo-metal–organic-framework (NiCo-MOF) nanosheets based on a facile protocol and then characterized them using multiple approaches (X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission-scanning electron microscopy (FE-SEM), and N2 adsorption/desorption isotherms techniques). As a sensitive electroactive material, the as-fabricated bimetallic NiCo-MOF nanosheets were employed to modify a screen-printed graphite electrode surface (NiCo-MOF/SPGE) for epinine electro-oxidation. According to the findings, there was a great improvement in the current responses of the epinine because of the appreciable electron transfer reaction and catalytic performance of the as-produced NiCo-MOF nanosheets. Differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry were utilized to analyze the electrochemical activity of the epinine on the NiCo-MOF/SPGE. A linear calibration plot was obtained in the broad concentration range (0.07–335.0 µM) with a high sensitivity (0.1173 µA/µM) and a commendable correlation coefficient (0.9997). The limit of detection (S/N = 3) was estimated at 0.02 µM for the epinine. According to findings from DPV, the electrochemical sensor of the NiCo-MOF/SPGE could co-detect epinine and venlafaxine. The repeatability, reproducibility and stability of the NiCo-metal–organic-framework-nanosheets-modified electrode were investigated, and the relative standard deviations obtained indicated that the NiCo-MOF/SPGE had superior repeatability, reproducibility and stability. The as-constructed sensor was successfully applicable in sensing the study analytes in real specimens.

In this study, we prepared graphene oxide (GO)/ZIF-67 nanocomposites. Therefore, GO/ZIF-67 nanocomposites were used as a modifier on a screen-printed electrode (GO/ZIF-67/SPE) for studying the electrochemical behavior of epinine in phosphate buffer saline (PBS) at pH 7.0 with voltammetry techniques. The GO/ZIF-67/SPE showed greater electrocatalytic activities than the bare SPE. As a result, the GO/ZIF-67/SPE was utilized for additional electrochemical examinations. The epinine concentration determination was in the range 9.0 × 10−8 M to 5.0 × 10−4 M, and the limit of detection (LOD) as well as the limit of quantification (LOQ) equaled 2.0 and 6.6 nM, respectively. From the scan rate study, the oxidation of epinine was found to be diffusion-controlled, and the simultaneous detection of epinine and dobutamine were well achieved with the differential pulse voltammetric (DPV) technique. Moreover, the stability and reproducibility of epinine at the GO/ZIF-67/SPE was studied, and the use of the GO/ZIF-67/SPE to detect epinine and dobutamine in real samples was furthermore successfully demonstrated.

A new and progressive electroanalytical sensor was made by the incorporation of Pt‐doped NiO nanoparticle (Pt‐NiO‐NPs) into carbon paste electrode (CPE) amplified with 1‐hexyl‐3‐methylimidazolium tetrafluoroborate (1H3MTFB) as a conductive binder. The Pt‐NiO‐NPs/1H3MTFB/CPE caused an extraordinary rise in the oxidation peak current of epinine (∼4.6 times) and simultaneous reduction in the oxidation over‐potential of catecholamine drug (∼120 mV). SWV method was employed to investigate the ability of Pt‐NiO‐NPs/1H3MTFB/CPE as an electroanalytical sensor in the determination of epinine in the presence of phenylephrine as two blood pressure raising drugs with ΔE=280 mV for the first time. Experimental results pertinent to SW voltammetric investigation reveal a linear relation between epinine and phenylephrine currents and drugs concentration in the rages 0.004–450 and 0.02–350 μM, respectively. [ABSTRACT FROM AUTHOR]

In this study, we prepared graphene oxide (GO)/ZIF-67 nanocomposites. Therefore, GO/ZIF-67 nanocomposites were used as a modifier on a screen-printed electrode (GO/ZIF-67/SPE) for studying the electrochemical behavior of epinine in phosphate buffer saline (PBS) at pH 7.0 with voltammetry techniques. The GO/ZIF-67/SPE showed greater electrocatalytic activities than the bare SPE. As a result, the GO/ZIF-67/SPE was utilized for additional electrochemical examinations. The epinine concentration determination was in the range 9.0 × 10−8 M to 5.0 × 10−4 M, and the limit of detection (LOD) as well as the limit of quantification (LOQ) equaled 2.0 and 6.6 nM, respectively. From the scan rate study, the oxidation of epinine was found to be diffusion-controlled, and the simultaneous detection of epinine and dobutamine were well achieved with the differential pulse voltammetric (DPV) technique. Moreover, the stability and reproducibility of epinine at the GO/ZIF-67/SPE was studied, and the use of the GO/ZIF-67/SPE to detect epinine and dobutamine in real samples was furthermore successfully demonstrated. [ABSTRACT FROM AUTHOR]

Cold exposure of rats for 4 h and simultaneous inhibition of dopamine β-hydroxylase by FLA-63 (25 mg/kg) led to a reduction of the catecholamine content of the adrenal medulla by 46% and of the brain by 68%. Additional injections of 5 mg/kg FLA-63 4 and 9 h after beginning of the experiments, respectively, kept the catecholamine content on this low level (brain) or decreased in further (adrenal medulla). Administration of 5 mg/kg (-)DOPA together with the mono-amine oxidase inhibitor pargyline (50 mg/kg) 24 h after the first injection of FLA-63 stimulated the resynthesis. It amounted for the adrenal medulla to 20 μg/kg body weight/8 h and for the brain to 45 ng/g tissue wet weight/8 h. Paper chromatographic analyses of the extracts of adrenal medulla and brain, respectively, performed at each time of the different injections, clearly identified adrenaline, noradrenaline and dopamine (in traces) in the adrenal medulla as well as noradrenaline and dopamine in the brain; epinine on the contrary could not be demonstrated, not even in traces. Since at least 25 ng of epinine can be detected with certainty by our method, it can be concluded that epinine is not formed in amounts greater than 75 ng/pair adrenal glands or 37.5 ng/brain. The present results support the view that the main pathway of adrenaline biosynthesis in the suprarenal medulla and the brain proceeds via noradrenaline and not via epinine. [ABSTRACT FROM AUTHOR]

Endogenous epinine was isolated from pig and bovine adrenal medulla and identified by means of thin layer chromatography and gas chromatography-mass fragmentography. By using labelled precursors, radioactive epinine was found to be formed in adrenal tissue slices and in whole perfused adrenal glands. These results suggest a possible and more logical pathway in the formation of adrenaline. [ABSTRACT FROM AUTHOR]

In 18 healthy volunteers, in a double-blind placebo-controlled study, we investigated of whether 14 days treatment with a therapeutic dose of ibopamine (3×100 mg/day p.o.), respectively its active metabolite epinine, would desensitize lymphocyte β- or platelet α-adrenoceptors, or α- and β-adrenoceptor mediated (phenylephrine-and isoprenaline infusions, respectively), changes in systolic and diastolic blood pressure and heart rate. Ibopamine-treatment, which resulted in peak plasma epinine concentrations of 4-5 nmol·l, neither affected resting heart rate or blood pressure, nor any of the α- or β-adrenoceptor parameters measured. Since in man in general long-term administration of α- and β-adrenoceptor agonists desensitizes α- and β-adrenoceptors, the lack of any α- and β-adrenoceptor desensitizing effect of ibopamine suggests that, in the dose employed (3×100 mg per day), ibopamine does not exert α- or β-adrenoceptor agonistic effect in humans. [ABSTRACT FROM AUTHOR]

Objective: The contractile response to digitalis and β adrenoceptor agonists is lower in the senescent than in the adult myocardium, while the development of ventricular arrhythmias is increased. The aim of this study was to examine the effects of aging on cardiac response to digitalis and an adrenergic agonist used clinically. Methods: The electrical and mechanical responses were tested in isolated and perfused hearts from 3-24 month old rats receiving 15 min infusion of digitalis drug (ouabain, 6 × 10−5 M) alone, and after 5 min of β adrenoceptor agonist drug (epinine, 1.5 × 10−7 M). Results: Ouabain action was associated with a rise in left ventricular end diastolic pressure (p<0.01) which increased progressively with aging, and with an elevation of left ventricular developed pressure (p<0.01) which decreased progressively with aging. Epinine induced a reduction of left ventricular end diastolic pressure (p<0.01) and a rise in left ventricular developed pressure (p<0.01) but both effects decreased progressively with aging. Ouabain reduced coronary flow and this decrease was more pronounced with aging (p<0.01), while epinine caused an increase (p<0.01) that diminished in older hearts. Ouabain given after epinine resulted in a greater increase in left ventricular end diastolic pressure than epinine (p<0.01) but lower than that caused by ouabain alone (p<0.01), a greater increase in left ventricular developed pressure than epinine and ouabain (p<0.01), and a smaller reduction of coronary flow rate than ouabain alone (p<0.01). All these effects, however, diminished progressively with aging. Arrhythmia scores were higher during ouabain than in control (p<0.01) and in epinine treated hearts (p<0.01); pretreatment with epinine did not modify arrhythmia score during ouabain administration. The number and severity of arrhythmias, however, increased with aging in all groups. Conclusions: Aging has a negative effect on both the positive inotropic and the arrhythmogenic effects of ouabain and epinine, although these phenomena are more pronounced during ouabain administration. However, when the two drugs are given simultaneously, epinine does not modify the arrhythmogenic effect of ouabain but reduces some of its deleterious haemodynamic effects.Cardiovascular Research 1994;28:358-364 [ABSTRACT FROM PUBLISHER]

Adrenaline (A) is synthesized in the adrenal medullae by the enzyme phenylethanolamine-N-methyltransferase (PNMT). After surgical removal of the adrenal medullae tissue A levels ranged from 22% of control in the heart to 125% of control in the liver. Use of a novel assay to measure tissue A formation revealed that many tissues can synthesize A using PNMT and another enzyme that N-methylates both noradrenaline and dopamine. These enzymes are non-neuronal, inducible and synthesize a major fraction of tissue and urine A. [ABSTRACT FROM AUTHOR]