Riluzole prevents MPTP-induced parkinsonism in the rhesus monkey: a pilot study

Subthalamic nucleus deep brain stimulation alleviates oxidative stress via mitophagy in Parkinson's disease

Subthalamic nucleus deep brain stimulation (STN-DBS) has the potential to delay Parkinson's disease (PD) progression. Whether oxidative stress participates in the neuroprotective effects of DBS and related signaling pathways remains unknown. To address this, we applied STN-DBS to mice and monkey models of PD and collected brain tissue to evaluate mitophagy, oxidative stress, and related pathway. To confirm findings in animal experiments, a cohort of PD patients was recruited and oxidative stress was evaluated in cerebrospinal fluid. When PD mice received STN stimulation, the mTOR pathway was suppressed, accompanied by elevated LC3 II expression, increased mitophagosomes, and a decrease in p62 expression. The increase in mitophagy and balance of mitochondrial fission/fusion dynamics in the substantia nigra caused a marked enhancement of the antioxidant enzymes superoxide dismutase and glutathione levels. Subsequently, fewer mitochondrial apoptogenic factors were released to the cytoplasm, which resulted in a suppression of caspase activation and reservation of dopaminergic neurons. While interfaced with an mTOR activator, oxidative stress was no longer regulated by STN-DBS, with no neuroprotective effect. Similar results to those found in the rodent experiments were obtained in monkeys treated with chronic STN stimulation. Moreover, antioxidant enzymes in PD patients were increased after the operation, however, there was no relation between changes in antioxidant enzymes and motor impairment. Collectively, our study found that STN-DBS was able to increase mitophagy via an mTOR-dependent pathway, and oxidative stress was suppressed due to removal of damaged mitochondria, which was attributed to the dopaminergic neuroprotection of STN-DBS in PD.

Identifying the dataset to define the optimal timing of histopathological examination for central nervous system toxicity in MPTP-induced Parkinson's disease monkey model

Determining the optimal timing for histopathological examination following exposure to a test article is crucial for assessing neurotoxicity. However, no study has focused on identifying an ideal dataset to define the optimal timing for histopathological examination of central nervous system (CNS) toxicity in monkeys. Therefore, this study aimed to define a predictive endpoint that would guide us in selecting the optimal timing for histopathological examination of CNS toxicity in monkeys. Four cynomolgus monkeys were administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intravenously at a dosage of 0.6 mg/kg twice at 1-week intervals. Necropsies were performed 1 week after the final dose. The Parkinsonian rating (PR) score and temporal changes in neurofilament light chain and glial fibrillary acidic protein concentrations in the cerebrospinal fluid (CSF) and serum were evaluated and compared with the histopathological findings in the brain. The PR score of all animals administered MPTP increased from days 10 to 11, with some degree of individual variability. Microscopically, all animals showed axonal swelling and vacuolation, with or without microgliosis in the nigrostriatal bundle. However, substantial neurodegenerative findings were observed only in animals with high PR scores at necropsy. A slight increase in CSF biomarker levels at necropsy was also observed in animals with high PR scores. However, their correlation with microscopic findings in these animals was unclear. These data suggest that comprehensive clinical observations, such as PR score alone or combined with other CSF biomarkers, could be further evaluated as potential indicators for triggering anatomic CNS evaluations in monkeys following toxic insults.

Review on the Developments of Benzothiazole-containing Antimicrobial Agents

The infectious diseases caused by bacterial resistance to antibiotics constitute an increasing threat to human health on a global scale. An increasing number of infections, including tuberculosis, pneumonia, salmonellosis and gonorrhea, are becoming progressively challenging to cure owing to the ineffectiveness of current clinically used antibiotics and presents a serious health threat worldwide in medical community. The major concern of this global health threat is the ability of microorganisms to develop one or several mechanisms of resistance to antibiotics, making them inefficient to therapeutic treatment. The quest for discovering novel scaffold with antimicrobial property is particularly in great need to face future challenges in hospital and healthcare settings. Hence, the development of benzothiazoles is of considerable interest to medicinal chemists. Benzothiazole, being part of an important class of heterocyclic scaffold retains a wide spectrum of various attractive pharmacological activities. Antibiotic resistance represents an increasing burden comprising medical cost, hospital stay and mortality. Several derivatives containing a benzothiazole scaffold, reported in the literature, were found to display remarkable potencies towards diverse Grampositive and Gram-negative bacterial pathogens. The principal focus concerns the antibacterial potential of benzothiazole-based derivatives as antimicrobial agents interacting with targets in bacterial pathogens. In this review, we also disclose the significance of the benzothiazole moiety in the discovery of new antibacterial compounds, the potential of benzothiazole-based derivatives in the case of resistant bacterial strains, optimization of their antibacterial activity, and their future perspectives. The structure-activity relationship study and the mode of action of the title derivatives are highlighted too.

2-Substituted Benzoxazoles as Potent Anti-Inflammatory Agents: Synthesis, Molecular Docking and In Vivo Anti-Ulcerogenic Studies

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are the commonly used therapeutic interventions of inflammation and pain that competitively inhibit the cyclooxygenase (COX) enzymes. Several side effects like gastrointestinal and renal toxicities are associated with the use of these drugs. The therapeutic anti-inflammatory benefits of NSAIDs are produced by the inhibition of COX-2 enzymes, while undesirable side effects arise from the inhibition of COX-1 enzymes.

OBJECTIVES

In the present study, a new series of 2-substituted benzoxazole derivatives 2(a-f) and 3(a-e) were synthesized in our lab as potent anti-inflammatory agents with outstanding gastro-protective potential. The new analogs 2(a-f) and 3(a-e) were designed depending upon the literature review to serve as ligands for the development of selective COX-2 inhibitors.

METHODS

The synthesized analogs were characterized using different spectroscopic techniques (FTIR, 1HNMR, 13CNMR) and elemental analysis. All synthesized compounds were screened for their binding potential in the protein pocket of COX-2 and evaluated for their anti-inflammatory potential in animals using the carrageenan-induced paw edema method. Further 5 compounds were selected to assess the in vivo anti-ulcerogenic activity in an ethanol-induced anti-ulcer rat model.

RESULTS

Five compounds (2a, 2b, 3a, 3b and 3c) exhibited potent anti-inflammatory activity and significant binding potential in the COX-2 protein pocket. Similarly, these five compounds demonstrated a significant gastro-protective effect (p<0.01) in comparison to the standard drug, Omeprazole.

CONCLUSION

Depending upon our results, we hypothesize that 2-substituted benzoxazole derivatives have excellent potential to serve as candidates for the development of selective anti-inflammatory agents (COX-2 inhibitors). However, further assessments are required to delineate their underlying mechanisms.

Modulation of dopamine tone induces frequency shifts in cortico-basal ganglia beta oscillations

Βeta oscillatory activity (human: 13-35 Hz; primate: 8-24 Hz) is pervasive within the cortex and basal ganglia. Studies in Parkinson's disease patients and animal models suggest that beta-power increases with dopamine depletion. However, the exact relationship between oscillatory power, frequency and dopamine tone remains unclear. We recorded neural activity in the cortex and basal ganglia of healthy non-human primates while acutely and chronically up- and down-modulating dopamine levels. We assessed changes in beta oscillations in patients with Parkinson's following acute and chronic changes in dopamine tone. Here we show beta oscillation frequency is strongly coupled with dopamine tone in both monkeys and humans. Power, coherence between single-units and local field potentials (LFP), spike-LFP phase-locking, and phase-amplitude coupling are not systematically regulated by dopamine levels. These results demonstrate that beta frequency is a key property of pathological oscillations in cortical and basal ganglia networks.

Visible-light-mediated one-pot efficient synthesis of 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles: a metal-free photochemical approach in aqueous ethanol

A new metal-free approach to construct medicinally valuable 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles under visible light irradiation in aqueous ethanol medium at room temperature has been developed. The present process was performed with 1,2-phenylenediamines, aromatic aldehydes and 2-mercaptoacetic acid utilizing a simple household 22 W compact fluorescent lamp to generate C-S, C-N bonds through radical intermediates. This visible-light-promoted synthesis provides lower cost, operation simplicity and high functional groups tolerating ability with short reaction time and high yield under mild reaction conditions.

Benzothiazoles from Condensation of o-Aminothiophenoles with Carboxylic Acids and Their Derivatives: A Review

Nowadays, organic chemists are interested in the field of heterocyclic chemistry due to its use in the synthesis of a great variety of biologically active compounds. Heterocyclic compounds are widely found in nature and are essential for life. Among these, some natural nitrogen containing heterocyclic compounds have been used as chemotherapeutic agents. Their attachment to sugar molecules either as thioglycosides or as nucleosides analogues plays an important role in vital biological processes as well as in synthetic organic chemistry. Molecules containing benzothiazole (BT) nuclei are of this interesting class of compounds because some of them have been found to have a wide variety of biological activities. In this sense, we selected this topic to review and to then summarize the procedures related to the condensation reactions of o-aminothiophenoles (ATPs) as well as their disulfides with carboxylic acids, esters, orthoesters, acyl chlorides, amides, and nitriles. The condensation reactions with carbon dioxide (CO₂) are included. Conventional methods with the use of acid and metal catalysts as well as recent green techniques, such as microwave irradiation, the use of ionic liquids, and ultrasound (US) chemistry, which have proven to have many advantages, were found in the review.

Synthesis, antimicrobial activity, density functional modelling and molecular docking with COVID-19 main protease studies of benzoxazole derivative: 2-(p-chloro-benzyl)-5-[3-(4-ethly-1-piperazynl) propionamido]-benzoxazole

This study contains synthesis, antimicrobial activity, density functional modelling and molecular docking studies of benzoxazole derivative: 2-(p-chloro-benzyl)-5-[3-(4-ethly-1-piperazynl) propionamido]-benzoxazole. The synthetic procedure of investigated compound is given in detail. The newly synthesized benzoxazole compound and standard drugs were evaluated for their antimicrobial activity against some Gram-positive, Gram-negative bacteria and fungus C. albicans and their drug-resistant isolates. The benzoxazole compound has been characterized by using ¹H-NMR, IR and MASS spectrometry and elemental analysis techniques. The molecular structure of the compound in the ground state has been modelling using density functional theory (DFT) with B3LYP/6-311++g(d,p) level. The molecular docking of 2-(p-chloro-benzyl)-5-[3-(4-ethly-1-piperazynl) propionamido]-benzoxazole with COVID-19 main protease has been also performed by using optimized geometry and the experimentally determined dimensional structure of the main protease (M-pro) of COVID-19.

Toward asleep DBS: cortico-basal ganglia spectral and coherence activity during interleaved propofol/ketamine sedation mimics NREM/REM sleep activity

Deep brain stimulation (DBS) is currently a standard procedure for advanced Parkinson's disease. Many centers employ awake physiological navigation and stimulation assessment to optimize DBS localization and outcome. To enable DBS under sedation, asleep DBS, we characterized the cortico-basal ganglia neuronal network of two nonhuman primates under propofol, ketamine, and interleaved propofol-ketamine (IPK) sedation. Further, we compared these sedation states in the healthy and Parkinsonian condition to those of healthy sleep. Ketamine increases high-frequency power and synchronization while propofol increases low-frequency power and synchronization in polysomnography and neuronal activity recordings. Thus, ketamine does not mask the low-frequency oscillations used for physiological navigation toward the basal ganglia DBS targets. The brain spectral state under ketamine and propofol mimicked rapid eye movement (REM) and Non-REM (NREM) sleep activity, respectively, and the IPK protocol resembles the NREM-REM sleep cycle. These promising results are a meaningful step toward asleep DBS with nondistorted physiological navigation.

Design, synthesis, molecular docking, density functional theory and antimicrobial studies of some novel benzoxazole derivatives as structural bioisosteres of nucleotides

A series of some novel 2-(p-tert-butylphenyl)-5-(3-substituted-propionamido)benzoxazole derivatives have been designed, synthesized, evaluated for antimicrobial activity and have performed molecular docking studies against penicillin-binding protein 4 (PBP4) and active and allosteric site of PBP2a; were calculated some theoretical quantum parameters and absorption, distribution, metabolism and excretion (ADME) descriptors. B9 acted at minimum inhibitory concentration (MIC) = 8 µg/mL against S. aureus, E. faecalis and their drug-resistant isolates and also formed with GLU145 (1.74 Å) and ILE144 (1.89 Å) two hydrogen bonds at allosteric site of PBP2a with Glide emodel score: -42.168. ΔE of compound B9 had moderate value of all compounds with 0.14742.[Formula: see text]Communicated by Ramaswamy H. Sarma.

Absence of a synergic nigral proapoptotic effect triggered by REM sleep deprivation in the rotenone model of Parkinson´s disease

Excitotoxicity has been related to play a crucial role in Parkinson's disease (PD) pathogenesis. Pedunculopontine tegmental nucleus (PPT) represents one of the major sources of glutamatergic afferences to nigrostriatal pathway and putative reciprocal connectivity between these structures may exert a potential influence on rapid eye movement (REM) sleep control. Also, PPT could be overactive in PD, it seems that dopaminergic neurons are under abnormally high levels of glutamate and consequently might be more vulnerable to neurodegeneration. We decided to investigate the neuroprotective effect of riluzole administration, a N-methyl-D-aspartate (NMDA) receptor antagonist, in rats submitted simultaneously to nigrostrial rotenone and 24h of REM sleep deprivation (REMSD). Our findings showed that blocking NMDA glutamatergic receptors in the SNpc, after REMSD challenge, protected the dopaminergic neurons from rotenone lesion. Concerning rotenone-induced hypolocomotion, riluzole reversed this impairment in the control groups. Also, REMSD prevented the occurrence of rotenone-induced motor impairment as a result of dopaminergic supersensitivity. In addition, higher Fluoro Jade C (FJC) staining within the SNpc was associated with decreased cognitive performance observed in rotenone groups. Such effect was counteracted by riluzole suggesting the occurrence of an antiapoptotic effect. Moreover, riluzole did not rescue cognitive impairment impinged by rotenone, REMSD or their combination. These data indicated that reductions of excitotoxicity, by riluzole, partially protected dopamine neurons from neuronal death and appeared to be effective in relieve specific rotenone-induce motor disabilities.

Effectiveness assessment of riluzole in the prevention of oxaliplatin-induced peripheral neuropathy: RILUZOX-01: protocol of a randomised, parallel, controlled, double-blind and multicentre study by the UNICANCER-AFSOS Supportive Care intergroup

INTRODUCTION

Most patients (>70%) experience acute neuropathic symptoms shortly after oxaliplatin infusions. These symptoms are not always resolved between infusions. Overall, 30%-50% of patients suffer from chronic oxaliplatin-induced peripheral neuropathy (OIPN). This cumulative and dose-dependent sensory neuropathy limits compliance or results in oxaliplatin-based chemotherapies to be substituted with less neurotoxic agents. These treatment changes impair clinical outcomes, and may be associated with comorbidities, such as distress, depression and anxiety. Currently, no drug used to prevent or treat OIPN is sufficiently effective to be used routinely in clinical practice. There is, thus, an unmet therapeutic need to reduce the intensity of and/or prevent OIPN. We hypothesised that riluzole would be an excellent candidate to address this public health issue. Riluzole is approved for treating amyotrophic lateral sclerosis. In animals, there is a beneficial effect on sensorimotor and pain disorders, as well as related comorbidities, after repeated administration of oxaliplatin. In humans, riluzole has shown neuroprotective, anxiolytic and antidepressive effects.

METHODS AND ANALYSIS

RILUZOX-01 trial was designed as a randomised, controlled, double-blind study to evaluate the efficacy of riluzole to prevent OIPN. Patients with colorectal cancer and initiating adjuvant oxaliplatin-based chemotherapy are eligible. Patients (n=210) will be randomly assigned to either riluzole or placebo, concomitantly with chemotherapy. The primary endpoint is the change in OIPN intensity, assessed by the sensory scale of the QLQ-CIPN20, after six 2-week cycles of chemotherapy. Secondary endpoints include incidence and severity of neuropathy, grade of sensory neuropathy, intensity and features of neuropathic pain, health-related quality of life, disease-free survival, overall survival and safety.

ETHICS AND DESSIMINATION

The study was approved by a French ethics committee (ref:39/18_1, 'Comité de Protection des Personnes' Ouest-IV, France) and plans to start enroling patients in September 2019. The trial is registered in EudraCT and clinicaltrials.gov.

TRIAL REGISTRATION NUMBER

N°2017-002320-25; NCT03722680.

Synthesis, Structure Revision, and Cytotoxicity of Nocarbenzoxazole G

The total synthesis of nocarbenzoxazoles F (1) and G (2), originally obtained from the marine-derived halophilic bacterial strain Nocardiopsis lucentensis DSM 44048, was achieved via a simple and versatile route involving microwave-assisted construction of a benzoxazole skeleton, followed by carbon-carbon bond formation with the corresponding aryl bromides. Unfortunately, the ¹H and ¹³C NMR spectra of natural nocarbenzoxazole G did not agree with those of the synthesized compound. In particular, the spectra of the isolated and synthesized compounds showed considerable differences in the signals from the protons and carbons in the aryl group. The revised structure was validated by the total synthesis of the actual nocarbenzoxazole G (8c) molecule, which is a regioisomer of the compound that was reported earlier as nocarbenzoxazole G. The synthesized derivatives showed specific cytotoxicity to the human cervical carcinoma cell line, HeLa, but did not have any remarkable effect on the other cell lines.

Thiol substrate-promoted dehydrogenative cyclization of arylmethyl thiols with ortho-substituted amines: a universal approach to heteroaromatic compounds

A thiol substrate-promoted one-pot synthesis of a library of heteroaromatic compounds was developed.

Synthesis and Evaluation of N-[1-(((3,4-Diphenylthiazol-2(3H)-ylidene)amino)methyl)cyclopentyl]acetamide Derivatives for the Treatment of Diseases Belonging to MAOs

A series of N-[1-(((3,4-diphenylthiazol-2(3H)-ylidene)amino)methyl)cyclopentyl]acetamide derivatives (4a-4i) were synthesized in good yield and assayed for their inhibitory potency against monoamine oxidase (MAO) isoforms. Structures of newly synthesized compounds were characterized by IR, 1H-NMR, 13C-NMR, and mass spectroscopic methods. The inhibitory activity of compounds (4a-4i) against hMAO-A and hMAO-B enzymes was elucidated by using in vitro fluorometric method using Amplex Red® reagent. In the hMAO-A inhibition assay, compounds 4a, 4b, 4c, and 4i exhibited similar activity with standard drug moclobemide (IC50 = 6.061 ± 0.262 µM) with IC50 values of 7.06 ± 0.18 µM, 6.56 ± 0.20 µM, 6.78 ± 0.15 µM, and 7.09 ± 0.17 µM, respectively. According to hMAO-B inhibition results, compounds 4a, 4b, and 4c displayed significant activity with IC50 values of 0.42 ± 0.012 µM, 0.36 ± 0.014 µM, and 0.69 ± 0.020 µM, respectively. In the wake of all these results, it was understood that compound 4b was found to be the most potent derivative in the series against both isoforms and selective as MAO-B inhibitor. The cytotoxicity test was performed for compounds 4a, 4b, and 4c, and it was found that these compounds were noncytotoxic at the concentration of their IC50 values. Also, enzyme kinetic and docking studies of compound 4b were performed against MAO-B. It was observed that 4b showed a reversible and noncompetitive inhibition type. The important binding modes of this compound with active site of hMAO-B were shown owing to in silico studies.

Benzoxazole derivatives: design, synthesis and biological evaluation

Background

A new series of benzoxazole analogues was synthesized and checked for their in vitro antibacterial, antifungal and anticancer activities.

Results and discussion

The synthesized benzoxazole compounds were confirmed by IR, ¹H/¹³C-NMR, mass and screened for their in vitro antimicrobial activity against Gram-positive bacterium: Bacillus subtilis, four Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi and two fungal strains: Candida albicans and Aspergillus niger using tube dilution technique and minimum inhibitory concentration (MIC) was noted in µM and compared to ofloxacin and fluconazole. Human colorectal carcinoma (HCT116) cancer cell line was used for the determination of in vitro anticancer activity (IC₅₀ value) by Sulforhodamine B assay using 5-fluorouracil as standard drug.

Conclusion

The performed study indicated that the compounds 1, 10, 13, 16, 19, 20 and 24 had highest antimicrobial activity with MIC values comparable to ofloxacin and fluconazole and compounds 4, 6, 25 and 26 had best anticancer activity in comparison to 5-fluorouracil.

Association of riluzole and dantrolene improves significant recovery after acute spinal cord injury in rats

BACKGROUND CONTEXT

Damage to the spinal cord can result in irreversible impairment or complete loss of motor, sensory, and autonomic functions. Riluzole and dantrolene have been shown to provide neuroprotection by reducing neuronal apoptosis after brain and spinal cord injury (SCI) in several animal models of neurologic disorders. As these drugs protect the injured spinal cord through different mechanisms, we investigated the cumulative effects of riluzole and dantrolene.

PURPOSE

This study aimed to investigate the neuroprotective efficacy of the combined administration of riluzole and dantrolene in experimental thoracic SCI.

STUDY DESIGN

Twenty-nine Wistar rats were laminectomized at T12 and divided in five groups. Rats in GI (n=6) underwent laminectomy alone and were treated with placebo. Rats in GII (n=6) underwent laminectomy followed by SCI and were treated with placebo. Rats in GIII (n=5) underwent laminectomy followed by SCI and were treated with riluzole and placebo 15 minutes and 1 hour after laminectomy, respectively. Rats in GIV (n=6) underwent laminectomy followed by SCI and were treated with placebo and dantrolene 15 minutes and 1 hour after laminectomy, respectively. Rats in GV (n=6) underwent laminectomy followed by SCI and were treated with riluzole and dantrolene 15 minutes and 1 hour after laminectomy, respectively. A compressive trauma was performed to induce SCI.

METHODS

Behavioral testing of hind limb function was performed using the Basso Beattie Bresnahan locomotor rating scale, which revealed significant recovery in the group treated with the association of riluzole and dantrolene compared with other groups. After euthanasia, the spinal cord was evaluated using light microscopy and immunochemistry with anti-NeuN and transferase dUTP nick-end-labeling (TUNEL) staining.

RESULTS

Animals treated with the association of riluzole and dantrolene showed a larger number of NeuN-positive neurons adjacent to the epicenter of injury (p≤.05). Furthermore, the TUNEL staining was similar between animals treated with riluzole and dantrolene and those that did not receive spinal cord trauma (p>.05).

CONCLUSIONS

These results showed that riluzole and dantrolene have a synergistic effect in neuroprotection after traumatic SCI by decreasing apoptotic cell death.

Serotonergic Approaches in Parkinson's Disease: Translational Perspectives, an Update

Parkinson's disease (PD) has long been seen as a disorder caused by degeneration of the dopaminergic system, leading to the classic motor manifestations of the disease. However, there is now overwhelming evidence that PD is more than a disease merely caused by dopamine depletion. It is well-known that a myriad of other neurotransmitters are affected by the disease process. One such neurotransmitter is serotonin (5-HT). 5-HT has been shown to play a role in several motor and nonmotor manifestations of PD, including tremor, cognition, depression and psychosis. 5-HT also seems to play a critical role in L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia. A breadth of preclinical studies and clinical trials have been conducted that aimed at modulating the 5-HT system in order to alleviate depression, cognitive deficits, psychosis, and dyskinesia. In this Review, we summarize recent advances in the 5-HT field in PD, but with a translational emphasis. We start by presenting a novel nonhuman primate model of PD that presents with dual dopamine and 5-HT lesions. We then present preclinical and clinical data that introduce new concepts, such as the use of biased and partial agonists, as well as molecules recently introduced to the field of PD, such as eltoprazine, pimavanserin, nelotanserin, and SYN-120, to enhance therapeutic benefit while minimizing adverse events, notably on parkinsonian disability.

Non-human primate models of PD to test novel therapies

Non-human primate (NHP) models of Parkinson disease show many similarities with the human disease. They are very useful to test novel pharmacotherapies as reviewed here. The various NHP models of this disease are described with their characteristics including the macaque, the marmoset, and the squirrel monkey models. Lesion-induced and genetic models are described. There is no drug to slow, delay, stop, or cure Parkinson disease; available treatments are symptomatic. The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-Dopa) still remains the gold standard symptomatic treatment of Parkinson. However, involuntary movements termed L-Dopa-induced dyskinesias appear in most patients after chronic treatment and may become disabling. Dyskinesias are very difficult to manage and there is only amantadine approved providing only a modest benefit. In this respect, NHP models have been useful to seek new drug targets, since they reproduce motor complications observed in parkinsonian patients. Therapies to treat motor symptoms in NHP models are reviewed with a discussion of their translational value to humans. Disease-modifying treatments tested in NHP are reviewed as well as surgical treatments. Many biochemical changes in the brain of post-mortem Parkinson disease patients with dyskinesias are reviewed and compare well with those observed in NHP models. Non-motor symptoms can be categorized into psychiatric, autonomic, and sensory symptoms. These symptoms are present in most parkinsonian patients and are already installed many years before the pre-motor phase of the disease. The translational usefulness of NHP models of Parkinson is discussed for non-motor symptoms.

Subthalamic, not striatal, activity correlates with basal ganglia downstream activity in normal and parkinsonian monkeys

The striatum and the subthalamic nucleus (STN) constitute the input stage of the basal ganglia (BG) network and together innervate BG downstream structures using GABA and glutamate, respectively. Comparison of the neuronal activity in BG input and downstream structures reveals that subthalamic, not striatal, activity fluctuations correlate with modulations in the increase/decrease discharge balance of BG downstream neurons during temporal discounting classical condition task. After induction of parkinsonism with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), abnormal low beta (8-15 Hz) spiking and local field potential (LFP) oscillations resonate across the BG network. Nevertheless, LFP beta oscillations entrain spiking activity of STN, striatal cholinergic interneurons and BG downstream structures, but do not entrain spiking activity of striatal projection neurons. Our results highlight the pivotal role of STN divergent projections in BG physiology and pathophysiology and may explain why STN is such an effective site for invasive treatment of advanced Parkinson's disease and other BG-related disorders.

DOI:http://dx.doi.org/10.7554/eLife.16443.001

The symptoms of Parkinson’s disease include tremor and slow movement, as well as loss of balance, depression and problems with sleep and memory. The death of neurons in a region of the brain called the substantia nigra pars compacta is one of the major hallmarks of Parkinson’s disease. These neurons produce a chemical called dopamine, and their death reduces dopamine levels in another area of the brain called the striatum. This structure is one of five brain regions known collectively as the basal ganglia, which form a circuit that helps to control movement.

The most effective treatment currently available for advanced Parkinson’s disease entails lowering electrodes deep into the brain in order to shut down the activity of part of the basal ganglia. However, the target is not the striatum; instead it is a structure called the subthalamic nucleus. The striatum and the subthalamic nucleus are the two input regions of the basal ganglia: each sends signals to the other three structures downstream. So why does targeting the subthalamic nucleus, but not the striatum, reduce the symptoms of Parkinson’s disease?

To shed some light on this issue, Deffains et al. recorded the activity of neurons in the basal ganglia before and after injecting two monkeys with a drug called MPTP. Related to heroin, MPTP produces symptoms in animals that resemble those of Parkinson’s disease. Before the injections, spontaneous fluctuations in the activity of the subthalamic nucleus produced matching changes in the activity of the three downstream basal ganglia structures. Fluctuations in the activity of the striatum, by contrast, had no such effect. Moreover, injecting the monkeys with MPTP caused the basal ganglia to fire in an abnormal highly synchronized rhythm, similar to that seen in Parkinson’s disease. Crucially, the subthalamic nucleus contributed to this abnormal rhythm, whereas the striatum did not.

The results presented by Deffains et al. provide a concrete explanation for why inactivating the subthalamic nucleus, but not the striatum, reduces the symptoms of Parkinson’s disease. Further research is now needed to explore how the striatum controls the activity of downstream regions of the basal ganglia, both in healthy people and in those with Parkinson's disease.

DOI:http://dx.doi.org/10.7554/eLife.16443.002

N-Adamantyl-4-methylthiazol-2-amine suppresses amyloid β-induced neuronal oxidative damage in cortical neurons

Recently, we have reported that N-adamantyl-4-methylthiazol-2-amine (KHG26693) successfully reduced the production of oxidative stress in streptozotocin-induced diabetic rats and lipopolysaccharide-induced BV-2 microglial cells by increasing their antioxidant capacity. However, antioxidative effects of KHG26693 against Aβ (Aβ)-induced oxidative stress have not yet been reported. In the present study, we further investigated the antioxidative function of KHG26693 in Aβ-mediated primary cultured cortical neurons. We showed here that KHG26693 attenuated Aβ-induced cytotoxicity, increase of Bax/Bcl-2 ratio, elevation of caspase-3 expression, and impairment of mitochondrial membrane potential in cultured primary cortical neurons. KHG26693 also decreases the Aβ-mediated formation of malondialdehyde, reactive oxygen species, and NO production by decreasing nitric oxide synthase (iNOS) and NADPH oxidase level. Moreover, KHG26693 suppress the Aβ-induced oxidative stress through a possible mechanism involving attenuation of GSH and antioxidant enzyme activities such as glutathione reductase and glutathione peroxidase (GPx). Finally, pretreatment of cortical neurons with KHG26693 significantly reduced the Aβ-induced protein oxidation and nitration. To our knowledge, this is the first report, showing that KHG26693 significantly attenuates Aβ-induced oxidative stress in primary cortical neurons, and may prove attractive strategies to reduce Aβ-induced neural cell death.

Animal behavioral assessments in current research of Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disorder, is traditionally classified as a movement disorder. Patients typically suffer from many motor dysfunctions. Presently, clinicians and scientists recognize that many non-motor symptoms are associated with PD. There is an increasing interest in both motor and non-motor symptoms in clinical studies on PD patients and laboratory research on animal models that imitate the pathophysiologic features and symptoms of PD patients. Therefore, appropriate behavioral assessments are extremely crucial for correctly understanding the mechanisms of PD and accurately evaluating the efficacy and safety of novel therapies. This article systematically reviews the behavioral assessments, for both motor and non-motor symptoms, in various animal models involved in current PD research. We addressed the strengths and weaknesses of these behavioral tests and their appropriate applications. Moreover, we discussed potential mechanisms behind these behavioral tests and cautioned readers against potential experimental bias. Since most of the behavioral assessments currently used for non-motor symptoms are not particularly designed for animals with PD, it is of the utmost importance to greatly improve experimental design and evaluation in PD research with animal models. Indeed, it is essential to develop specific assessments for non-motor symptoms in PD animals based on their characteristics. We concluded with a prospective view for behavioral assessments with real-time assessment with mobile internet and wearable device in future PD research.

Experimental and theoretical approving of anomeric based oxidation in the preparation of 2-sbstituted benz-(imida, oxa and othia)-zoles using [2,6-DMPy-NO2]C(NO2)3 as a novel nano molten salt catalyst

The synthesis of [2,6-DMPy-NO₂]C(NO₂)₃ as a novel NMS and its application in the synthesis of 2-sbstituted benz-(imida, oxa and othia)-zoles via a new mechanistic approach was supported by theoretical studies.

Near-infrared light is neuroprotective in a monkey model of Parkinson disease

OBJECTIVE

To examine whether near-infrared light (NIr) treatment reduces clinical signs and/or offers neuroprotection in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey model of Parkinson disease.

METHODS

We implanted an optical fiber device that delivered NIr (670 nm) to the midbrain of macaque monkeys, close to the substantia nigra of both sides. MPTP injections (1.5-2.1mg/kg) were made over a 5- to 7-day period, during which time the NIr device was turned on. This was then followed by a 3-week survival period. Monkeys were evaluated clinically (eg, posture, bradykinesia) and behaviorally (open field test), and their brains were processed for immunohistochemistry and stereology.

RESULTS

All monkeys in the MPTP group developed severe clinical and behavioral impairment (mean clinical scores = 21-34; n = 11). By contrast, the MPTP-NIr group developed much less clinical and behavioral impairment (n = 9); some monkeys developed moderate clinical signs (mean scores = 11-15; n = 3), whereas the majority--quite remarkably--developed few clinical signs (mean scores = 1-6; n = 6). The monkeys that developed moderate clinical signs had hematic fluid in their optical fibers at postmortem, presumably limiting NIr exposure and overall clinical improvement. NIr was not toxic to brain tissue and offered neuroprotection to dopaminergic cells and their terminations against MPTP insult, particularly in animals that developed few clinical signs.

INTERPRETATION

Our findings indicate NIr to be an effective therapeutic agent in a primate model of the disease and create the template for translation into clinical trials.

Study on molecular structure, spectroscopic behavior, NBO, and NLO analysis of 3-methylbezothiazole-2-thione

Experimentally observed spectral data (FT-TR and FT-Raman) of 3-methylbezothiazole-2-thione (3MBT2T) were compared with the spectral data obtained by DFT/B3LYP method using 6-311++G(d,p) basis set. UV-Vis spectrum of the title compound was recorded and the electronic properties, such as frontier molecular orbitals and band gap energies were calculated by TD-DFT approach. The molecular properties like dipole moment, polarizability, first static hyperpolarizability, molecular electrostatic potential surface (MEPs), and contour map were calculated to get a better comprehension of the properties of the title molecule. Natural bond orbital (NBO) analysis was applied to investigate the stability of the molecule arising from charge delocalization. Global and local reactivity descriptors were also computed to predict reactivity and reactive sites on the molecule.