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L-DOPA, the precursor of catecholamines, exerts a pro-locomotor action in several vertebrate species, including newborn rats. Here, we tested the hypothesis that decreasing the degradation of monoamines can promote the pro-locomotor action of a low, subthreshold dose of L-DOPA in five-day-old rats. The activity of the degrading pathways involving monoamine oxidases or catechol-O-methyltransferase was impaired by injecting nialamide or tolcapone, respectively. At this early post-natal stage, the capacity of the drugs to trigger locomotion was investigated by monitoring the air-stepping activity expressed by the animals suspended in a harness above the ground. We show that nialamide (100 mg/kg) or tolcapone (100 mg/kg), without effect on their own promotes maximal expression of air-stepping sequences in the presence of a sub-effective dose of L-DOPA (25 mg/kg). Tissue measurements of monoamines (dopamine, noradrenaline, serotonin and some of their metabolites) in the cervical and lumbar spinal cord confirmed the regional efficacy of each inhibitor toward their respective enzyme. Our experiments support the idea that the raise of monoamines boost L-DOPA's locomotor action. Considering that both inhibitors differently altered the spinal monoamines levels in response to L-DOPA, our data also suggest that maximal locomotor response can be reached with different monoamines environment. [ABSTRACT FROM AUTHOR]

Rationale: Positive allosteric modulation of metabotropic glutamate type 4 (mGlu4) receptors is a promising strategy to alleviate parkinsonian disability and L-3,4-dihydroxyphenylalanine (L-DOPA) induced dyskinesia. ADX-88178 is a highly selective mGlu4 positive allosteric modulator (PAM) that previously enhanced the anti-parkinsonian action of L-DOPA in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease (PD). Objectives: We sought to explore the effects of ADX-88178 on psychosis-like behaviours (PLBs) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset. We also aimed to determine the effect of ADX-88178 on parkinsonism and dyskinesia. Methods: Six MPTP-lesioned marmosets were administered L-DOPA chronically to induce stable PLBs and dyskinesias. They were then administered ADX-88178 (0.01, 0.1 and 1 mg/kg) or vehicle, in combination with L-DOPA/benserazide (15/3.75 mg/kg), both sub-cutaneously, in a randomised fashion. PLBs, parkinsonism and dyskinesia were then measured. Results: ADX-88178 mildly worsened global PLBs at the dose of 1 mg/kg (by 13%, P = 0.020). L-DOPA alone conferred 158 min of on-time, while the duration of on-time was 212 min (34% increase, P = 0.011), after adding ADX-88178 1 mg/kg to L-DOPA. Accordingly, ADX-88178 1 mg/kg reduced global parkinsonian disability, by 38% (P = 0.0096). ADX-88178 1 mg/kg diminished peak dose dyskinesia by 34% (P = 0.015). Minimal effects were provided by lower doses. Conclusions: Whereas these results provide additional evidence of the anti-parkinsonian and anti-dyskinetic effects of mGlu4 positive allosteric modulation as an adjunct to L-DOPA, they also suggest that ADX-88178 may exacerbate dopaminergic psychosis. Further studies are needed to evaluate this possible adverse effect of mGlu4 PAMs on PD psychosis. [ABSTRACT FROM AUTHOR]

Discovering alternative analytical techniques is crucial for practical applications; thus, this work aims to develop an innovative and simple electrochemical sensor for melanoma and the clinical diagnosis of related disorders by the simultaneous determination of 3,4-dihydroxy-l-phenylalanine (l-DOPA) and l-tyrosine (l-Tyr). The fabrication is based on the layer-by-layer electrodeposition of poly l-proline (poly(L-pro)) and nanodiamond (ND) onto a screen-printed graphene electrode (SPGE). The poly(l-pro)/ND/SPGEs were morphologically characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and Raman spectroscopy followed by electrochemical investigation using cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. These modifier-based electrodes pave a feasible way to unlock the coexisting interfering substances from screen-printing ink composition and improve the sensitivity. Additionally, computational chemistry calculations were performed to fully comprehend the sensing behavior on both target analytes. Under optimal conditions, the developed sensor provided linear concentration ranges of 0.075–50 μM, with a detection limit of 0.021 μM for l-DOPA, and 2.5–120 μM with a detection limit of 0.74 μM for l-Tyr. To demonstrate the reliability of the poly(l-pro)/ND/SPGE in practical application, it was successfully applied to the determination of these analytes in human urine and blood serum samples, with satisfactory recovery ranges (81.73–110.62% for l-DOPA and 82.17–110.01% for l-Tyr) and relative standard deviations (0.69–9.90% for l-DOPA and 0.40–9.55% for l-Tyr). Due to its simplicity, long-term stability (> 87.8% of their initial currents after 35 days), and portability, the developed sensor is a promising alternative analytical method for on-site clinical monitoring. [ABSTRACT FROM AUTHOR]

In a significant percentage of breast cancers, increased expression of the HER2 receptor is seen and is associated with the spread and worsening of the disease. This research aims to investigate the effect of miR-559 (which targets HER2 mRNA) on SKBR3 breast cancer cells and the possibility of their effective delivery with polymeric nanoparticles and tumor-targeting peptides. L-DOPA monomers were polymerized on the surface of silica nanoparticles in the presence of miR-559 (as a molecular template for molecular imprinting) then an anti-HER2 peptide coupled to the surface of these polymeric nanocomposites (miR-NC-NL2), and the effects of this construct against a HER2-positive breast cancer cells (SKBR3 cells) investigated in vitro conditions. The results showed that miR-NC-NL2 is selective for HER2-positive cells and delivers the miR-559 to them in a targeted manner. miR-NC-NL2 decreased the proliferation of SKBR3 cells and reduced the expression and production of HER2 protein in these cells. Effective and targeted delivery of miR-559 to HER2-positive cancer cells by the miR-NC-NL2 promises the therapeutic potential of this nascent structure based on its inhibitory effect on cancer growth and progression. Of course, animal experiments require a better understanding of this structure's anti-tumor effects. [ABSTRACT FROM AUTHOR]

L-Dopa is an intermediate amino acid in the biosynthesis of endogenous catecholamines, such as dopamine. It is currently considered to be the optimal dopaminergic treatment for Parkinson's disease, a neurodegenerative disorder affecting around 1% of the population. In an advanced stage of the disease, complications such as dyskinesia and psychosis are caused by fluctuations in plasma drug levels. Real-time monitoring of L-Dopa levels would be advantageous for properly adjusting drug dosing, thus improving therapeutic efficacy. Electrochemical methods have advantages such as easy-to-use instrumentation, fast response time, and high sensitivity, and are suitable for miniaturization, enabling the fabrication of implantable or wearable devices. This review reports on research papers of the past 20 years (2003–2023) dealing with enzyme-based biosensors for the electrochemical detection of L-Dopa in biological samples. Specifically, amperometric and voltammetric biosensors, whose output signal is a measurable current, are discussed. The approach adopted includes an initial study of the steps required to assemble the devices, i.e., electrode modification and enzyme immobilization. Then, all issues related to their analytical performance in terms of sensitivity, selectivity, and capability to analyze real samples are critically discussed. The paper aims to provide an assessment of recent developments while highlighting limitations such as poor selectivity and long-term stability, and the laborious and time-consuming fabrication protocol that needs to be addressed from the perspective of the integrated clinical management of Parkinson's disease. [ABSTRACT FROM AUTHOR]

Objective(s): Parkinson’s disease (PD) is one of the most incurable, chronic, and progressive neurodegenerative disorders Worldwide. Curcumin, a natural polyphenolic antioxidant compound, has a long history in traditional medicine. We investigate the effect of curcumin on brain oxidative stress, DNA fragmentation, and motor changes in rotenone-induced PD in mice. The possible modulation of the anti-parkinsonian action of drugs L-dopa and rasagiline by curcumin was also studied.Materials and Methods: Mice received rotenone 1.5 mg/kg and were treated with curcumin (150 mg/kg), L-dopa (25 mg/kg), rasagiline (1 mg/kg), L-dopa+curcumin, or rasagiline+curcumin. Striatal malondialdehyde, reduced glutathione, nitric oxide, tyrosine hydroxylase, and brain DNA fragmentations were measured. Histopathological examination of brain tissues was done. Motor coordination and behavioral tests such as wire-hanging, stair, and wood-waking tests were included.Results: Rotenone caused elevation in brain malondialdehyde and nitric oxide contents, depletion of reduced glutathione accompanied by a reduction in rearing behavior, and impairment of motor activity in wire-hanging, stair, and wood-waking tests. Also, severe DNA fragmentation in the striatum, marked decrease of substantia nigra pigmented neurons, neuronal degeneration in the cerebral cortex and hippocampus, decreased glial fibrillary acidic protein reaction (GFAP) and glial cell size in the cerebral cortex were caused by rotenone. In rotenone-treated mice, brain oxidative stress was decreased by curcumin, L-dopa, rasagiline, curcumin+L-dopa, and curcumin+rasagiline. These treatments also prevented DNA fragmentation and markedly improved the motor and behavioral impairment caused by rotenone. Rotenone-induced histopathological changes were ameliorated by curcumin which had an additive effect to that of l-dopa or rasagiline.Conclusion: These data indicate that curcumin showed additive neuroprotective effects to L-dopa or rasagiline and ameliorated neurodegeneration, DNA fragmentation, and motor defects caused by rotenone in mice.

Abstract Tyrosine hydroxylase deficiency (THD) is a rare genetic disorder leading to dopaminergic depletion and early‐onset Parkinsonism. Affected children present with either a severe form that does not respond to L‐Dopa treatment (THD‐B) or a milder L‐Dopa responsive form (THD‐A). We generated induced pluripotent stem cells (iPSCs) from THD patients that were differentiated into dopaminergic neurons (DAn) and compared with control‐DAn from healthy individuals and gene‐corrected isogenic controls. Consistent with patients, THD iPSC‐DAn displayed lower levels of DA metabolites and reduced TH expression, when compared to controls. Moreover, THD iPSC‐DAn showed abnormal morphology, including reduced total neurite length and neurite arborization defects, which were not evident in DAn differentiated from control‐iPSC. Treatment of THD‐iPSC‐DAn with L‐Dopa rescued the neuronal defects and disease phenotype only in THDA‐DAn. Interestingly, L‐Dopa treatment at the stage of neuronal precursors could prevent the alterations in THDB‐iPSC‐DAn, thus suggesting the existence of a critical developmental window in THD. Our iPSC‐based model recapitulates THD disease phenotypes and response to treatment, representing a promising tool for investigating pathogenic mechanisms, drug screening, and personalized management.

The theory of electron spin has been proposed for a century, but the study of quantum effects in biological molecules is still in its infancy. Chirality-induced spin selectivity (CISS) is a very modern theory that can explain many biochemical phenomena. In this paper, we propose a new theoretical model based on CISS theory and quantum chemistry theory, which can well explain the theoretical explanation of the chiral selectivity of chiral proteins. Moreover, this theory can predict the spin state of corresponding chiral molecules. Taking the L-DOPA and AADC enzymes as examples, this theoretical model elucidates the AADC enzyme's chiral catalysis selectivity and successfully predicts the spin state of L-DOPA and D-DOPA's valence electrons. [ABSTRACT FROM AUTHOR]

Background: Iron deficiency is the leading cause of anemia worldwide, particularly in countries with predominant plant-based diets. Plants constitute the main source of dietary iron. Increasing their iron concentration could reduce the occurrence of anemia. The water spinach Ipomoea aquatica is consumed as a vegetable throughout Asia and tolerates high iron concentrations making it an attractive candidate for iron biofortification. L-DOPA is an allelopathic molecule secreted by some legumes. L-DOPA can trigger the expression of Fe deficiency-inducible genes, and could potentially be used as a biostimulant to increase Fe concentration. Results: L-DOPA significantly affected root growth of water spinach, and triggered a massive accumulation of Fe in roots. Both effects were exacerbated when L-DOPA was dissolved in KOH, which is surprising given that L-DOPA is less stable at high pH. To check whether a higher pH could indeed increase the bioactivity of L-DOPA, we used Arabidopsis thaliana, which grows at lower pH than water spinach, and subjected the plants to L-DOPA treatments at pH 5.5 and pH 6.0, which are both within the optimal range for Arabidopsis nutrition. At pH 6.0, the root growth of Arabidopsis was more strongly inhibited than at pH 5.5. We found that at higher pH, L-DOPA oxidizes to form a melanin precipitate. Conclusions: We concluded that the oxidation of L-DOPA that we observed upon solubilization in KOH, or in nutrient solutions at slightly higher pH produces melanin-related molecules that are more potent than L-DOPA itself to trigger the primary root growth inhibition, Fe uptake and root Fe accumulation in water spinach and Arabidopsis. [ABSTRACT FROM AUTHOR]

Our suggestion is that a new approach to PD diagnosis and management beyond dopamine replacement therapy should be rapidly adopted, encompassing all clinical features and addressing their contribution to early disease detection, prognosis, progression and quality of life. Impulsivity and ICD are more common in patients on DA replacement treatment especially dopamine agonists.[[24], [26]] This supports the notion that ICD is related to dopaminergic dysfunction and can be managed only by modulation of dopamine replacement therapy. Keywords: l-dopa; Parkinson; motor complications; progression EN l-dopa Parkinson motor complications progression S50 S55 6 08/28/23 20230802 NES 230802 Introduction Diagnosis and clinical burden in people with Parkinson's disease (PD) is often related to the cardinal motor features (tremor, bradykinesia, rigidity) and occurs when at least 40-60% of striatal dopamine nerve terminals are lost.[1] However, in the "Essay on the shaking palsy" James Parkinson already reported presence of constipation, cognitive dysfunction or sleep disorders in addition to motor involvement.[2] With the introduction of l-dopa therapy it became evident that only specific clinical features would improve while many others would show limited or no benefit from medications even if they significantly contribute to quality of life decline and disability. Recent discoveries in disease biomarkers indicate that it is important to change our dopamine-centric perspective for PD diagnosis if we want to test and possibly implement disease modifying therapies before motor symptoms become manifest.[40] Acknowledgments Figure 1 was created with BioRender.com. [Extracted from the article]

Wheat powdery mildew (Bgt), a fungal seeding disease, is a threat to wheat agriculture worldwide. In this study, iron shell wheat (Triticum aestivum ssp. yunnanense King) was used as the research material. Extensive targeted metabolomic analysis was conducted on the leaves of the susceptible strain iron shell wheat 1 (DiKe 1) and the normal resistant strain Zhenkang iron shell wheat (Yunmai 0030). Furthermore, the dynamic physiological changes in metabolite levels between the two strains were assessed. Significant differences were identified in tryptophan and pyrimidine metabolism as well as isoquinoline alkaloid biosynthesis. The main metabolites were phenolic acids, flavonoid carboglycosides, indole alkaloids, phenolic amines, amino acids, and their derivatives. The defense response to powdery mildew in the iron shell wheat was dominated by tryptophan metabolism. The importance of L-dopa and tyramine in powdery mildew resistance provides new insights into the relevant mechanisms and can help identify antigens for use in the breeding of powdery-mildew-resistant wheat varieties. [ABSTRACT FROM AUTHOR]

Zonisamide (ZNS; 1,2-benzisoxazole-3-methanesulfonamide) was initially developed and is commonly used as an anticonvulsant drug. However, it has also shown its beneficial effects on Parkinson's disease (PD), a progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the midbrain. Recent clinical studies have suggested that ZNS can also have beneficial effects on L-DOPA-induced dyskinesia (LID), which is a major side effect of long-term L-DOPA treatments for PD. In the present study, we examined the behavioral effects of ZNS on LID in PD model mice. Acute ZNS treatment did not have any observable behavioral effects on LID. Contrastingly, chronic ZNS treatment with L-DOPA delayed the peak of LID and reduced the severity of LID before the peak but increased the duration of LID in a dose-dependent manner of ZNS compared to PD model mice treated with L-DOPA alone. Thus, ZNS appears to have both beneficial and adverse effects on LID. [ABSTRACT FROM AUTHOR]

Background: Parkinson's Disease (PD) is a debilitating neurodegenerative disease suffered by elderly population worldwide. There are different treatment options for its symptomatic relief including the use of inhibitors of monoamine oxidase-B, acetylcholinesterase enzymes and L-DOPA though with certain side effects. Materials and Methods: To identify new resources of natural products with potential effects to treat PD, several Indian Ocimum species, e.g., O. tenuiflorum (green), O. tenuiflorum (purple), O. basilicum, O. americanum, O. kilimandscharicum, and O. gratissimum were screened. Activities of the extracts were studied against monoamine Oxidase-B (MAO-B), and acetylcholinesterase (AChE). Identification of active components present in these extracts was determined using GC-MS and LC-MS metabolites profiling. Further, activity of identified phenolics was measured by docking score against MAO-B and AChE. Results: All extracts and several phenolics showed potential inhibition of these two PD related enzymes based on in vitro and in silico, respectively. Ellagic acid-di-methyl ether-O-glucoside, rosmarinic acid, and luteolin-5-glucuronide were identified as top scoring hits against both AChE and MAO-B from molecular docking studies. L-DOPA was also detected in all the species of Ocimum. Conclusion: IC50 values against both enzymes and L-DOPA levels detected in O. tenuiflorum (green), O. basilicum, and O. americanum pose them as potential nutraceuticals for PD treatment. [ABSTRACT FROM AUTHOR]

L-Dopa, a bioactive compound naturally occurring in some Leguminosae plants, is the most effective symptomatic drug treatment for Parkinson's disease. During disease progression, fluctuations in L-DOPA plasma levels occur, causing motor complications. Sensing devices capable of rapidly monitoring drug levels would allow adjusting L-Dopa dosing, improving therapeutic outcomes. A novel amperometric biosensor for L-Dopa detection is described, based on tyrosinase co-crosslinked onto a graphene oxide layer produced through electrodeposition. Careful optimization of the enzyme immobilization procedure permitted to improve the long-term stability while substantially shortening and simplifying the biosensor fabrication. The effectiveness of the immobilization protocol combined with the enhanced performances of electrodeposited graphene oxide allowed to achieve high sensitivity, wide linear range, and a detection limit of 0.84 μM, suitable for L-Dopa detection within its therapeutic window. Interference from endogenous compounds, tested at concentrations levels typically found in drug-treated patients, was not significant. Ascorbic acid exhibited a tyrosinase inhibitory behavior and was therefore rejected from the enzymatic layer by casting an outer Nafion membrane. The proposed device was applied for L-Dopa detection in human plasma, showing good recoveries. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects motor and cognition functions. The etiology of Parkinson's disease remains largely unknown, but genetic and environmental factors are believed to play a role. The neurotransmitter dopamine is implicated in regulating movement, motivation, memory, and other physiological processes. In individuals with Parkinson's disease, the loss of dopaminergic neurons leads to a reduction in dopamine levels, which causes motor impairment and may also contribute to the cognitive deficits observed in some patients. Therefore, it is important to understand the pathophysiology that leads to the loss of dopaminergic neurons, along with reliable biomarkers that may help distinguish PD from other conditions, monitor its progression, or indicate a positive response to a therapeutic intervention. Important advances in the treatment, etiology, and pathogenesis of Parkinson's disease have been made in the past 50 years. Therefore, this review tries to explain the different possible mechanisms behind the depletion of dopamine in PD patients such as alpha-synuclein abnormalities, mitochondrial dysfunction, and 3,4-dihydroxyphenylacetaldehyde (DOPAL) toxicity, along with the current therapies we have and the ones that are in development. The clinical aspect of Parkinson's disease such as the manifestation of both motor and non-motor symptoms, and the differential diagnosis with similar neurodegenerative disease are also discussed. [ABSTRACT FROM AUTHOR]

Mucuna pruriens (L.) DC var. pruriens is a well-known legume of Fabaceae family. The plant is the natural source of l -DOPA, precursor molecule of dopamine neurotransmitter used in the treatment of Parkinson´s disease. In M. pruriens , the Catecholamine (CA) biosynthesis is mediated by Polyphenol oxidase (PPO) as validated in our previous reports. In the present investigation, we identified three PPO isoforms and were quantitatively analyzed by quantitative real-time PCR to understand the expression of PPO´s constitutively in the different tissues of M. pruriens. Consequently, the highly expressed PPO isoform was cloned, and the recombinant protein purified followed by functional characterization. The Kinetic analysis using Lineweaver-Burk curves showed greater binding affinity of enzyme towards its specific substrate. This study provides new insight into plant derived recombinant PPO enzyme, which is involved in CA biosynthetic pathway in this taxon. The Metabolic pathway engineering of PPO step would result in modulation of l -DOPA synthesis in this plant, in future. [Display omitted] • Identified and confirmed the existence of PPO as isoforms in M. pruriens. • Quantitative expression of the highest expressed isoform using qRT-PCR. • Functional characterization of recombinantly expressed purified PPO. [ABSTRACT FROM AUTHOR]

Statins have been proposed for L-DOPA-induced dyskinesia (LID) treatment. Statin anti-dyskinetic effects were related to the inhibition of the Ras-ERK pathway. However, the mechanisms responsible for the anti-LID effect are unclear. Changes in cholesterol homeostasis and oxidative stress- and inflammation-related mechanisms such as angiotensin II and Rho-kinase (ROCK) inhibition may be involved. The nigra and striatum of dyskinetic rats showed increased levels of cholesterol, ROCK, and the inflammatory marker IL-1β, which were reduced by the angiotensin type-1 receptor (AT1) antagonist candesartan, simvastatin, and the ROCK inhibitor fasudil. As observed for LID, angiotensin II-induced, via AT1, increased levels of cholesterol and ROCK in the rat nigra and striatum. In cultured dopaminergic neurons, angiotensin II increased cholesterol biosynthesis and cholesterol efflux without changes in cholesterol uptake. In astrocytes, angiotensin induced an increase in cholesterol uptake, decrease in biosynthesis, and no change in cholesterol efflux, suggesting a neuronal accumulation of cholesterol that is reduced via transfer to astrocytes. Our data suggest mutual interactions between angiotensin/AT1, cholesterol, and ROCK pathways in LID, which are attenuated by the corresponding inhibitors. Interestingly, these three drugs have also been suggested as neuroprotective treatments against Parkinson's disease. Therefore, they may reduce dyskinesia and the progression of the disease using common mechanisms. [ABSTRACT FROM AUTHOR]

Levodopa is the most effective medication for treating Parkinson's disease (PD). However, because dose optimization is currently based on patients' report of symptoms, which are difficult for patients to describe, the management of PD is challenging. We report on a microneedle sensing platform for continuous minimally invasive orthogonal electrochemical monitoring of levodopa (L-Dopa). The new multimodal microneedle sensing platform relies on parallel simultaneous independent enzymatic-amperometric and nonenzymatic voltammetric detection of L-Dopa using different microneedles on the same sensor array patch. Such real-time orthogonal L-Dopa sensing offers a built-in redundancy and enhances the information content of the microneedle sensor arrays. This is accomplished by rapid detection of L-Dopa using square-wave voltammetry and chronoamperometry at unmodified and tyrosinase-modified carbon-paste microneedle electrodes, respectively. The new wearable microneedle sensor device displays an attractive analytical performance with the enzymatic and nonenzymatic L-Dopa microneedle sensors offering different dimensions of information while displaying high sensitivity (with a low detection limit), high selectivity in the presence of potential interferences, and good stability in artificial interstitial fluid (ISF). The attractive analytical performance and potential wearable applications of the microneedle sensor array have been demonstrated in a skin-mimicking phantom gel as well as upon penetration through mice skin. The design and attractive analytical performance of the new orthogonal wearable microneedle sensor array hold considerable promise for reliable, continuous, minimally invasive monitoring of L-Dopa in the ISF toward optimizing the dosing regimen of the drug and effective management of Parkinson disease.

Parkinson's disease (PD) is a neurodegenerative disorder that features progressive, disabling motor symptoms, such as bradykinesia, rigidity, and resting tremor. Nevertheless, some non-motor symptoms, including depression, REM sleep behavior disorder, and olfactive impairment, are even earlier features of PD. At later stages, apathy, impulse control disorder, neuropsychiatric disturbances, and cognitive impairment can present, and they often become a heavy burden for both patients and caregivers. Indeed, PD increasingly compromises activities of daily life, even though a high variability in clinical presentation can be observed among people affected. Nowadays, symptomatic drugs and non-pharmaceutical treatments represent the best therapeutic options to improve quality of life in PD patients. The aim of the present review is to provide a practical, stage-based guide to pharmacological management of both motor and non-motor symptoms of PD. Furthermore, warning about drug side effects, contraindications, as well as dosage and methods of administration, are highlighted here, to help the physician in yielding the best therapeutic strategies for each symptom and condition in patients with PD.

In this study, microbial production of L-Dopa and Dopamine which is an important substrance for the treatment of Parkinson's disease were investigated by using Citrobacter freundii (NRRL B-2643). The effects of carbon source (sucrose) and, salt concentrations (NaCl, CaCl2), initial pH, temperature, inoculum level and shaking speed on L-Dopa and dopamine production were investigated. The amounts of extracellular L-dopa and dopamine were determined by using HPLC. Maximum L-dopa and dopamine production, under optimized conditions (sucrose: 2.5 g/L, NaCl and CaCl2: 1.0 g/L, inoculum level: 1.0% (v/v), initial pH: 6.5, temperature: 33°C, shaking speed: 200 rpm) were found to be 458 and 592 mg/L, respectively. Although the experiments were carried out for 60 hours, but the maximum production of L-Dopa and Dopamine was realized at around the 30th hour of the experiments.

Abstract Background Melanin is a natural pigment that can be applied in different fields such as medicine, environment, pharmaceutical, and nanotechnology. Studies carried out previously showed that the melanin produced by the mel1 mutant from Aspergillus nidulans exhibits antioxidant, anti-inflammatory, and antimicrobial activities, without any cytotoxic or mutagenic effect. These results taken together suggest the potential application of melanin from A. nidulans in the pharmaceutical industry. In this context, this study aimed to evaluate the effect of factors L-tyrosine, glucose, glutamic acid, l-DOPA, and copper on melanin production by the mel1 mutant and to establish the optimal concentration of these factors to maximize melanin production. Results The results showed that l-DOPA, glucose, and copper sulfate significantly affected melanin production, where l-DOPA was the only factor that exerted a positive effect on melanin yield. Besides, the tyrosinase activity was higher in the presence of l-DOPA, considered a substrate required for enzyme activation, this would explain the increased production of melanin in this condition. After establishing the optimal concentrations of the analyzed factors, the melanin synthesis was increased by 640% compared to the previous studies. Conclusions This study contributed to elucidating the mechanisms involved in melanin synthesis in A. nidulans as well as to determining the optimal composition of the culture medium for greater melanin production that will make it possible to scale the process for a future biotechnological application.

Levodopa (l-dopa) is a gold standard neurological drug for symptomatic medication of Parkinson's disease. The long-term use of l-dopa therapy frequently leads to l-dopa-induced dyskinesia and several other non-motor flocculants for fluctuating plasma concentration. To alleviate the adverse effect of dopamine replacement therapy, sensitive detection of l-dopa is still challenging. Therefore, this study presents a simple strategy to develop an inexpensive, easy-to-use, smartphone-based fluorescence turn-on sensory system based on the aggregation-induced emission enhancement phenomenon for instant low-level detection of l-dopa in biological samples. The sensor was fabricated using silk-fibroin-decorated reduced graphene oxide quantum dots, which exhibit a progressive increase of fluorescence intensity in the presence of l-dopa. By measuring the turn-on efficiency of the sensor in elevated concentrations of l-dopa, the limit of detection (LOD) was evaluated as 76.18 nM over a linear range of 0–35 μM. We have further designed a smartphone-based electronic device involving a 365 nm light emitting diode attached below the rare camera for capturing the change of fluorescent color of the solution during sensing. From these images, red, green, and blue values are analyzed using a mobile phone application, and the corresponding LOD was found to be 0.29 μM in a similar linear range of concentration. This simple, cost-effective, and rapid screening gadget is very demanding for on-spot detection of the analytes in remote areas where sophisticated instrumentation is not usually available. [ABSTRACT FROM AUTHOR]

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Parkinson's disease (PD) is a neurological disorder characterized by progressive degeneration of the substantia nigra that affects mainly movement control. However, pathological changes associated with the development of PD may also alter respiration and can lead to chronic episodes of hypoxia and hypercapnia. The mechanism behind impaired ventilation in PD is unclear. Therefore, in this study, we explore the hypercapnic ventilatory response in a reproducible reserpine-induced (RES) model of PD and parkinsonism. We also investigated how dopamine supplementation with L-DOPA, a classic drug used to treat PD, would affect the breathing and respiratory response to hypercapnia. Reserpine treatment resulted in decreased normocapnic ventilation and behavioral changes manifested as low physical activity and exploratory behavior. The respiratory rate and the minute ventilation response to hypercapnia were significantly higher in sham rats compared to the RES group, while the tidal volume response was lower. All of this appears to be due to reduced baseline ventilation values produced by reserpine. L-DOPA reversed reduced ventilation, indicating a stimulatory effect of DA on breathing, and showed the potency of DA supplementation in restoring normal respiratory activity. [ABSTRACT FROM AUTHOR]

Mangiferin is a strong antioxidant that presents a wide range of biological activities. The aim of this study was to evaluate, for the first time, the influence of mangiferin on tyrosinase, an enzyme responsible for melanin synthesis and the unwanted browning process of food. The research included both the kinetics and molecular interactions between tyrosinase and mangiferin. The research proved that mangiferin inhibits tyrosinase activity in a dose-dependent manner with IC50 290 +/− 6.04 µM, which was found comparable with the standard kojic acid (IC50 217.45 +/− 2.54 µM). The mechanism of inhibition was described as mixed inhibition. The interaction between tyrosinase enzyme and mangiferin was confirmed with capillary electrophoresis (CE). The analysis indicated the formation of two main, and four less significant complexes. These results have also been supported by the molecular docking studies. It was indicated that mangiferin binds to tyrosinase, similarly to L-DOPA molecule, both in the active center and peripheral site. As it was presented in molecular docking studies, mangiferin and L-DOPA molecules can interact in a similar way with surrounding amino acid residues of tyrosinase. Additionally, hydroxyl groups of mangiferin may interact with amino acids on the tyrosinase external surface causing non-specific interaction. [ABSTRACT FROM AUTHOR]

The faba bean (Vicia faba L. var. major) is a pulse that is garnering attention for its chemical composition, which makes it suitable for a healthy diet. The Apulian germplasm is rich in local accessions at risk of genetic erosion, which need evaluating and promoting. Thirteen Vicia faba local Landraces have been analyzed in relation to their productivity and their chemical and biochemical characteristics: their protein, total phenol, total flavonoid, condensate tannin and L-DOPA levels. The results showed great variability—above all in the thousand-seeds weight and in their content of proteins and L-DOPA. Among the accessions evaluated, the two collected from the most southern area of the region (FV12-FV10) were particularly promising—both for their good biochemical traits and, especially, for the higher L-DOPA content (0.46 and 0.49 g 100 g−1 d.m., respectively), even when expressed in terms of yield per plant (116.3 and 153.0 mg plant−1 d.m., respectively). [ABSTRACT FROM AUTHOR]

Adenosine antagonism, i.e. of the A2A receptor, improves dopamine-sensitive motor behavior in patients with Parkinson's disease with oral levodopa-associated motor complications. Only the xanthine derivative istradefylline is currently approved in Japan and in the US. This compound easily crosses the blood–brain barrier and shows high affinity to A2A receptors. This narrative review discusses the place of istradefylline in the current available drug portfolio for Parkinson's disease following a literature research in PubMed. Istradefylline is safe and well tolerated. Its efficacy was pronounced, when patients were on a lower chronic oral levodopa regimen. Levodopa causes a homocysteine elevation, which reflects an impaired methylation potential. As a result, an upregulation of A2A receptor occurs and weakens the efficacy of istradefylline as modulator of dopamine effects on motor behavior in Parkinson's disease. This is the hypothetical reason why clinical trials failed, when patients were on a higher chronic levodopa regimen. A way out of this dilemma is to enable higher dosing of istradefylline and substitution of L-dopa with compounds, which do not influence the methylation capacity. Long-term trials may show these levodopa sparing and thus motor complications delaying effects of istradefylline. Stimulation of adenosine receptors antagonizes the beneficial effects of dopamine on movement. Accordingly, the adenosine receptor antagonist istradefylline was approved for the treatment of advanced patients with Parkinson's disease, who were treated with levodopa, the blood–brain barrier trespassing precursor of dopamine. Patients have to suffer from so-called levodopa-associated motor complications, which are characterized by intervals with good and bad motor behavior. Clinical trials showed that istradefylline co-administration improved these fluctuations of movement. This review aims to define a broader role and potential of istradefylline for the treatment armamentarium of Parkinson's disease. Increasing dosing of levodopa weakens the methylation potential in the brain as a result of the methyl group consuming conversion of levodopa to 3-O-methyldopa in glial cells. Impaired methylation causes an upregulation of adenosine receptors. This augmented availability of adenosine receptors weakens the effects of istradefylline. Therefore, clinical trials in patients with a higher levodopa dosage failed in contrast to studies with patients on a lower levodopa dose. This review suggests long-term investigations, which aim to demonstrate that istradefylline has the potential to delay the need for levodopa in the treatment of patients with Parkinson's disease. [ABSTRACT FROM AUTHOR]

Background and Purpose: Regulator of G‐protein signalling 4 (RGS4) is a signal transduction protein that accelerates intrinsic GTPase activity of Gαi/o and Gαq subunits, suppressing GPCR signalling. Here, we investigate whether RGS4 modulates nociceptin/orphanin FQ (N/OFQ) opioid (NOP) receptor signalling and if this modulation has relevance for l‐Dopa‐induced dyskinesia. Experimental Approach HEK293T cells transfected with NOP, NOP/RGS4 or NOP/RGS19 were challenged with N/OFQ and the small‐molecule NOP agonist AT‐403, using D1‐stimulated cAMP levels as a readout. Primary rat striatal neurons and adult mouse striatal slices were challenged with either N/OFQ or AT‐403 in the presence of the experimental RGS4 chemical probe, CCG‐203920, and D1‐stimulated cAMP or phosphorylated extracellular signal regulated kinase 1/2 (pERK) responses were monitored. In vivo, CCG‐203920 was co‐administered with AT‐403 and l‐Dopa to 6‐hydroxydopamine hemilesioned rats, and dyskinetic movements, striatal biochemical correlates of dyskinesia (pERK and pGluR1 levels) and striatal RGS4 levels were measured. Key Results: RGS4 expression reduced NOFQ and AT‐403 potency and efficacy in HEK293T cells. CCG‐203920 increased N/OFQ potency in primary rat striatal neurons and potentiated AT‐403 response in mouse striatal slices. CCG‐203920 enhanced AT‐403‐mediated inhibition of dyskinesia and its biochemical correlates, without compromising its motor‐improving effects. Unilateral dopamine depletion caused bilateral reduction of RGS4 levels, which was reversed by l‐Dopa. l‐Dopa acutely up‐regulated RGS4 in the lesioned striatum. Conclusions and Implications: RGS4 physiologically inhibits NOP receptor signalling. CCG‐203920 enhanced NOP responses and improved the antidyskinetic potential of NOP receptor agonists, mitigating the effects of striatal RGS4 up‐regulation occurring during dyskinesia expression. LINKED ARTICLES: This article is part of a themed issue on Advances in Opioid Pharmacology at the Time of the Opioid Epidemic. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.7/issuetoc [ABSTRACT FROM AUTHOR]

Fragrances are volatile organic compounds widely used in our daily life. Unfortunately, the high volatility required to reach human receptors reduces their persistency in the air. To contrast this effect, several strategies may be used. Among them, we present here the combination of two techniques: the microencapsulation in supramolecular gels and the use of profragrances. We report a study on the controlled lactonization of four esters derived from o-coumaric acid. The ester lactonization spontaneously occurs after exposure to solar light, releasing coumarin and the corresponding alcohol. To determine the rate of fragrance release, we compared the reaction in solution and in a supramolecular gel and we demonstrated that the lactonization reaction always occurs slower in the gel. We also studied the more suitable gel for this aim, by comparing the properties of two supramolecular gels obtained with the gelator Boc-L-DOPA(Bn)2-OH in a 1:1 ethanol/water mixture in different gelator concentration (0.2% and 1% w/v). The gel prepared with 1% w/v gelator concentration is stronger and less transparent than the other and was used for the profragrances encapsulation. In any case, we obtained a significative reduction of lactonization reaction in gel, compared with the same reaction in solution. [ABSTRACT FROM AUTHOR]

Background and aims: Chronic stress is a major common cause of male infertility. Many species of velvet beans are shown to be rich in l-DOPA. In Thai folklore medicine, seeds of Mucuna pruriens (L.) DC. var. pruriens (Thai Mhamui or T-MP) have been used for treating erectile dysfunction. This study aimed to determine l-DOPA levels in T-MP seed extract and investigate its preventive on sexual behaviors and reproductive parameter damages including essential proteins in chronic unpredictable mild stress (CUMS) mice. Experimental procedure: Mice were divided into 4 groups: (I) control, (II) CUMS, (III) T-MP300 + CUMS, and (IV) T-MP600 + CUMS. Groups I and II received DW while groups III and IV were pretreated with the seed extracts (300 and 600 mg/kg BW) for 14 consecutive days before co-treatment with a randomly different CUMS/day (from 12 mild stressors) for 43 days. Results and conclusion: T-MP seed extract contained l-DOPA approximately 10% of total dried weight. A dose of 600 mg/kg improved sexual performances and degenerative seminiferous epithelium in CUMS mice. Sperm qualities and testosterone level were elevated while corticosterone was decreased in co-treatment groups. T-MP-CUMS cotreated groups also improved expressions of AKAP4, AR, and TyrPho proteins in testis, epididymis, and sperm. T-MP increased StAR and CYP11A1 expressions in testis. It also suppressed testicular apoptosis via decreased expressions of Hsp70, caspases 3, and 9. T-MP seeds containing l-DOPA could improve sexual behaviors and essential reproductive proteins caused by CUMS. Section: Natural Products; Taxonomy (classification by evise): Traditional Herbal Medicine; Animal Model; Histopathology.

Experimental efforts aimed at detecting levodopa (l-DOPA) using surface-enhanced Raman scattering (SERS) face a persistent challenge in obtaining a SERS signal with negatively charged nanoparticles. This challenge stems from the repulsion between deprotonated l-DOPA in aqueous solution and the charged surface of the nanoparticles, revealing dependencies on time and concentration to achieve the SERS signal. This study explores the adsorption mechanism of l-DOPA on the surface of gold nanorods (AuNRs) covered with a cetrimonium bromide (CTAB) bilayer as a colloidal solution, subsequently dried onto a solid substrate such as glass, silicon, and Au substrate. Experimental findings are supported by density functional theory theoretical calculations. The comparison between experimental and theoretical results highlights that the SERS profile can be attributed to the adsorption of l-DOPA via the catechol ring, leading to the formation of anionic and dianionic species. [ABSTRACT FROM AUTHOR]

Mutations of proline-rich transmembrane protein 2 (PRRT2) lead to dyskinetic and convulsive disorders such as paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile seizure and hemiplegic migraine. PKD is characterized by attacks of involuntary movements precipitated by suddenly initiated motion. Previous studies have shown that PKD might be caused by cerebellar dysfunction; however, considering widespread expression of Prrt2 in the whole brain, it is likely that some other motor-related regions including the basal ganglia, where dopaminergic neurons are most abundant in the brain, might also be a part of pathogenesis of PKD. Here, we generated Prrt2 knock-in (KI) mice harboring mutation c.672dupG that mimics the human pathological mutation c.649dupC and investigated the role of Prrt2 in the basal ganglia. The mutant transcript and protein were abolished within the striatum, confirming loss-of-function nature of PKD and related disorders. Importantly, intrastriatal microdialysis revealed that the Prrt2 mutation dramatically elevated extracellular dopamine levels during the depolarized state, which might result from the increase in dopamine release because pharmacological inhibition of dopamine reuptake produced a greater elevation of extracellular dopamine levels in Prrt2-KI mice than in wild-type mice. Moreover, administration of L-dopa, a precursor of dopamine, exacerbated rotarod performance of Prrt2-KI mice more severely than that of wild-type mice. Overall, these findings suggest that dopaminergic dysfunction within the basal ganglia by the PRRT2 mutation might be implicated in a part of motor symptoms of PKD and related disorders. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of levodopa (L-dopa), p-coumaric acid, and combinations in the neuroblastoma (N1E-115) cell. L-dopa and L-dopa plus p-coumaric acid group caused oxidative stress by increasing 12.5 and 3.7-fold in superoxide dismutase gene, 11.5 and 4.8-fold increase in catalase gene, respectively. In L-dopa and L-dopa plus p-coumaric acid application, p21 gene expression increased 1.3-fold and 3.2-fold, and the cell cycle stopped in the G1 phase in response to stress in the treatment groups. In the application of L-dopa plus p-coumaric acid to N1E-115 cells, the BCL-2 gene, which is an apoptosis inhibitor, was suppressed and the BAX gene increased 13-fold compared to the control. As a result, it was determined that the cytotoxic effect of L-dopa plus p-coumaric acid application was less than the individual application of the substances, and p-coumaric acid had an inhibitory effect on L-dopa-induced stress.

Nitric oxide (NO) plays a pivotal role in integrating dopamine transmission in the basal ganglia and has been implicated in the pathogenesis of Parkinson disease (PD). The objective of this study was to ascertain whether the NO synthase inhibitor, 7-nitroindazole (7-NI), is able to reduce L-DOPA-induced dyskinesias (LIDs) in a non-human primate model of PD chronically intoxicated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Six Parkinsonian macaques were treated daily with L-DOPA for 3–4 months until they developed LIDs. Three animals were then co-treated with a single dose of 7-NI administered 45 min before each L-DOPA treatment. Dyskinetic MPTP-treated monkeys showed a significant decrease in LIDs compared with their scores without 7-NI treatment (p < 0.05). The anti-Parkinsonian effect of L-DOPA was similar in all three monkeys with and without 7-NI co-treatment. This improvement was significant with respect to the intensity and duration of LIDs while the beneficial effect of L-DOPA treatment was maintained and could represent a promising therapy to improve the quality of life of PD patients.

Tyrosine hydroxylase deficiency (THD) is a rare genetic disorder leading to dopaminergic depletion and early‐onset Parkinsonism. Affected children present with either a severe form that does not respond to L‐Dopa treatment (THD‐B) or a milder L‐Dopa responsive form (THD‐A). We generated induced pluripotent stem cells (iPSCs) from THD patients that were differentiated into dopaminergic neurons (DAn) and compared with control‐DAn from healthy individuals and gene‐corrected isogenic controls. Consistent with patients, THD iPSC‐DAn displayed lower levels of DA metabolites and reduced TH expression, when compared to controls. Moreover, THD iPSC‐DAn showed abnormal morphology, including reduced total neurite length and neurite arborization defects, which were not evident in DAn differentiated from control‐iPSC. Treatment of THD‐iPSC‐DAn with L‐Dopa rescued the neuronal defects and disease phenotype only in THDA‐DAn. Interestingly, L‐Dopa treatment at the stage of neuronal precursors could prevent the alterations in THDB‐iPSC‐DAn, thus suggesting the existence of a critical developmental window in THD. Our iPSC‐based model recapitulates THD disease phenotypes and response to treatment, representing a promising tool for investigating pathogenic mechanisms, drug screening, and personalized management. Synopsis: This is the first proof of principle that iPSC‐derived dopaminergic (DA) neurons from mild (THDA) and severe (THDB) patients reproduce distinct disease‐related features and reveal abnormal morphologies. The study highlights the importance of prenatal treatment with L‐Dopa in cases of THDB. THDA and THDB‐iPSCs produce fewer DA neurons than control‐iPSCs, as judged by reduced numbers of TH+ cell and TH protein expression.THDA and THDB‐iPSC‐derived DA neurons exhibit low intracellular DA levels and its metabolites and reduced expression of other DA markers, indicating impaired DA neuron function.DA neurons generated from both THD patient‐specific iPSCs show altered neuronal morphology (fewer and shorter neurites) compared to healthy controls.THDA neuronal defects can be recovered with L‐Dopa treatment.L‐Dopa added at an early stage of neural differentiation leads to prevention of neuronal defects in THDB cells. [ABSTRACT FROM AUTHOR]

Tropical vegetables remain one of the major sources of functional foods and nutraceuticals, while their constituent phytochemicals, especially alkaloids, have been reported to exhibit neuroprotective properties. Here, the protective effect of alkaloid extracts from Scent leaf (Ocimum gratissimum) and Water bitter leaf (Struchium sparganophora) on manganese (Mn)- induced toxicity in wild type fruit fly (Drosophila melanogaster) model was investigated. Flies were exposed to 30 mM of Mn, the alkaloid extracts (20 and 200 µg/g) and co-treatment of Mn plus extracts, respectively. The survival rate and locomotor performance of the flies were assessed 7 days post-treatment, after which the flies were homogenized and assayed for activities of acetylcholinesterase (AChE), monoamine oxidase (MAO), glutathione-S transferase (GST), catalase, superoxide dismutase SOD), as well as total thiol, reactive oxygen species (ROS) and neural L-DOPA levels. Results showed that the extract significantly reversed Mn-induced reduction in the survival rate and locomotor performance of the flies. Furthermore, both extracts counteracted the Mn-induced elevation in AChE and MAO activities, as well as reduced antioxidant enzyme activities, with a concomitant mitigation of Mn-induced elevated ROS and neural L-DOPA level. The HPLC characterization of the extracts revealed the presence of N-propylamine, Vernomine and Piperidine as predominant in Water bitter leaf extract, while 2, 6-dimethylpyrazine and sesbanimide were found in scent leaf extract. Therefore, the alkaloid extract of these leaves may thus be sources of useful nutraceuticals for the management of pathological conditions associated with manganese toxicity. [ABSTRACT FROM AUTHOR]

An efficient and reproducible protocol for Agrobacterium rhizogenes-mediated hairy root were efficiently induced from in vitro grown leaf explants of H. enneaspermus. Among the diverse factors analysed, acetosyringone (100 µM), sonication (40 s), and vacuum infiltration (2 min) followed by 2 days co-cultivation period revealed maximal percentage of hairy root induction using A4 strain (29.6%). PCR analysis were confirmed the transgenic status of hairy root by using rol B gene specific primer. Further, the highest amount of fresh weight (17.71 g) and dry weight (2.14 g) was noted at 40-day old A. rhizogenes induced hairy root cultures. Precursor L-tyrosine (100 µM) treated hairy roots produced higher L-Dopa (32.71 mg/g DW) content when compared with control culture. The transformation procedure designed in the current research could be valuable to transferring the gene of interest for secondary metabolism that was introduced into hairy roots of Hybanthus, and it could provide a feasible and sustained product platform for naturally derived, high quality and potential phytochemicals. [ABSTRACT FROM AUTHOR]

Parkinson's Disease (PD) is one of the most common non-curable neurodegenerative diseases. Diagnosis is achieved clinically on the basis of different symptoms with considerable delays from the onset of neurodegenerative processes in the central nervous system. In this study, we investigated early and full-blown PD patients based on the analysis of their voice characteristics with the aid of the most commonly employed machine learning (ML) techniques. A custom dataset was made with hi-fi quality recordings of vocal tasks gathered from Italian healthy control subjects and PD patients, divided into early diagnosed, off-medication patients on the one hand, and mid-advanced patients treated with L-Dopa on the other. Following the current state-of-the-art, several ML pipelines were compared usingdifferent feature selection and classification algorithms, and deep learning was also explored with a custom CNN architecture. Results show how feature-based ML and deep learning achieve comparable results in terms of classification, with KNN, SVM and naïve Bayes classifiers performing similarly, with a slight edge for KNN. Much more evident is the predominance of CFS as the best feature selector. The selected features act as relevant vocal biomarkers capable of differentiating healthy subjects, early untreated PD patients and mid-advanced L-Dopa treated patients. [ABSTRACT FROM AUTHOR]

Objective(s): Parkinson's disease (PD) is one of the most incurable, chronic, and progressive neurodegenerative disorders Worldwide. Curcumin, a natural polyphenolic anti-oxidant compound, has a long history in traditional medicine. We investigate the effect of curcumin on brain oxidative stress, DNA fragmentation, and motor changes in rotenone-induced PD in mice. The possible modulation of the anti-parkinsonian action of drugs L-dopa and rasagiline by curcumin was also studied. Materials and Methods: Mice received rotenone 1.5 mg/kg and were treated with curcumin (150 mg/kg), L-dopa (25 mg/kg), rasagiline (1 mg/kg), L-dopa+curcumin, or rasagiline+curcumin. Striatal malondialdehyde, reduced glutathione, nitric oxide, tyrosine hydroxylase, and brain DNA fragmentations were measured. Histopathological examination of brain tissues was done. Motor coordination and behavioral tests such as wire-hanging, stair, and wood-waking tests were included. Results: Rotenone caused elevation in brain malondialdehyde and nitric oxide contents, depletion of reduced glutathione accompanied by a reduction in rearing behavior, and impairment of motor activity in wire-hanging, stair, and wood-waking tests. Also, severe DNA fragmentation in the striatum, marked decrease of substantia nigra pigmented neurons, neuronal degeneration in the cerebral cortex and hippocampus, decreased glial fibrillary acidic protein reaction (GFAP) and glial cell size in the cerebral cortex were caused by rotenone. In rotenone-treated mice, brain oxidative stress was decreased by curcumin, L-dopa, rasagiline, curcumin+L-dopa, and curcumin+rasagiline. These treatments also prevented DNA fragmentation and markedly improved the motor and behavioral impairment caused by rotenone. Rotenone-induced histopathological changes were ameliorated by curcumin which had an additive effect to that of l-dopa or rasagiline. Conclusion: These data indicate that curcumin showed additive neuroprotective effects to L-dopa or rasagiline and ameliorated neurodegeneration, DNA fragmentation, and motor defects caused by rotenone in mice. [ABSTRACT FROM AUTHOR]

L‐DOPA is in large demand as the mainstay of therapeutic treatment for Parkinson's disease. The development of a facile route is urgently required for production of L‐DOPA. A nanozyme was developed for biomimetic synthesis of L‐DOPA by mimicking natural tyrosine hydroxylase. Fe3O4/g‐C3N4 nanocomposite was fabricated by introducing iron oxide into g‐C3N4 nanosheets. Formation of Fe−N bonds with structure resembled the active center. The nanozyme possessed superparamagnetic characteristics and wide light response range. The nanozyme exhibited similar activity as tyrosine hydroxylase by catalyzing hydroxylation of tyrosine in the presence of visible light irradiation and hydrogen peroxide. Maximum yield and titer was obtained as 15% and 1 mM for production of L‐DOPA, respectively. The nanozyme demonstrated high stability and reusability. The nanozyme catalyzed the reaction in an analogous mechanism with FeIVO2+ as the dominant active species. It might provide a promising insight to produce L‐DOPA due to advantages of easy separation and mild conditions. [ABSTRACT FROM AUTHOR]

L‐dopa variably influences transcranial magnetic stimulation (TMS) parameters of motor cortex (M1) excitability and plasticity in Parkinson's disease (PD). In patients OFF dopaminergic medication, impaired M1 plasticity and defective GABA‐A‐ergic inhibition can be restored by boosting gamma (γ) oscillations via transcranial alternating current stimulation (tACS) during intermittent theta‐burst stimulation (iTBS). However, it is unknown whether L‐dopa modifies the beneficial effects of iTBS‐γ‐tACS on M1 in PD. In this study, a PD patients group underwent combined iTBS‐γ‐tACS and iTBS‐sham‐tACS, each performed both OFF and ON dopaminergic therapy (four sessions in total). Motor evoked potentials (MEPs) elicited by single TMS pulses and short‐interval intracortical inhibition (SICI) were assessed before and after iTBS‐tACS. We also evaluated possible SICI changes during γ‐tACS delivered alone in OFF and ON conditions. The amplitude of MEP elicited by single TMS pulses and the degree of SICI inhibition significantly increased after iTBS‐γ‐tACS. The amount of change produced by iTBS‐γ‐tACS was similar in patients OFF and ON therapy. Finally, γ‐tACS (delivered alone) modulated SICI during stimulation and this effect did not depend on the dopaminergic condition of patients. In conclusion, boosting cortical γ oscillatory activity via tACS during iTBS improved M1 plasticity and enhanced GABA‐A‐ergic transmission in PD patients to the same extent regardless of dopaminergic state. These results suggest a lack of interaction between L‐dopa and γ‐tACS effects at the M1 level. The possible neural substrate underlying iTBS‐γ tACS effects, that is, γ‐resonant GABA‐A‐ergic interneurons activity, may explain our findings. [ABSTRACT FROM AUTHOR]