Decreased Dopamine Levels Research Articles

Molecular Docking, Bioinformatic Analysis, and Experimental Verification for the Effect of Naringin on ADHD: Possible Inhibition of GSK-3β and HSP90

Background/Objectives: One of the most abundant and growing neurodevelopmental disorders in recent decades is attention deficit hyperactivity disorder (ADHD). Many trials have been performed on using drugs for the improvement of ADHD signs. This study aimed to detect the possible interaction of naringin with Wnt/β-catenin signaling and its putative anti-inflammatory and protective effects in the mouse ADHD model based on bioinformatic, behavioral, and molecular investigations. Furthermore, molecular docking was applied to investigate possible interactions with the GSK-3β and HSP90 proteins. Methods: Male Swiss albino mice were divided into four groups, a normal control group, monosodium glutamate (SGL) control, SGL + naringin 50 mg/kg, and SGL + naringin 100 mg/kg. The psychomotor activity of the mice was assessed using the self-grooming test, rope crawling test, and attentional set-shifting task (ASST). In addition, biochemical analyses were performed using brain samples. Results: The results of the SGL group showed prolonged grooming time (2.47-folds), a lower percentage of mice with successful crawling on the rope (only 16.6%), and a higher number of trials for compound discrimination testing in the ASST (12.83 ± 2.04 trials versus 5.5 ± 1.88 trials in the normal group). Treatment with naringin (50 or 100 mg per kg) produced significant shortening in the grooming time (31% and 27% reductions), as well as a higher percentage of mice succeeding in crawling with the rope (50% and 83%, respectively). Moreover, the ELISA assays indicated decreased dopamine levels (0.36-fold) and increased TNF-α (2.85-fold) in the SGL control group compared to the normal mice, but an improvement in dopamine level was observed in the naringin (50 or 100 mg per kg)-treated groups (1.58-fold and 1.97-fold). Similarly, the PCR test showed significant declines in the expression of the Wnt (0.36), and β-catenin (0.33) genes, but increased caspase-3 (3.54-fold) and BAX (5.36-fold) genes in the SGL group; all these parameters were improved in the naringin 50 or 100 mg/kg groups. Furthermore, molecular docking indicated possible inhibition for HSP90 and GSK-3β. Conclusions: Overall, we can conclude that naringin is a promising agent for alleviating ADHD symptoms, and further investigations are required to elucidate its mechanism of action.

Dietary Natural Flavonoids: Intervention for MAO-B Against Parkinson's Disease.

Parkinson's disease (PD) stands as the second most common neurological disorder after Alzheimer's disease, primarily affecting the elderly population and significantly compromising their quality of life. The precise etiology of PD remains elusive, but recent research has shed light on potential factors, including the formation of α-synuclein aggregates, oxidative stress, neurotransmitter imbalances, and dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc) region of the brain, culminating in motor symptoms such as bradykinesia, akinesia, tremors, and rigidity. Monoamine oxidase (MAO) is an essential enzyme, comprising two isoforms, MAO-A and MAO-B, responsible for the oxidation of monoamines such as dopamine. Increased MAO-B activity is responsible for decreased dopamine levels in the SNpc region of mid brain which is remarkably associated with the pathogenesis of PD-like manifestations. Inhibitors of MAO-B enhance striatal neuronal responses to dopamine, making them valuable in treating PD, which involves dopamine deficiency. Clinically approved MAO-B inhibitors such as selegiline, L-deprenyl, pargyline, and rasagiline are employed in the management of neurodegenerative conditions associated with PD. Current therapeutic interventions including MAO-B inhibitors for PD predominantly aim to alleviate these motor symptoms but often come with a host of side effects that can be particularly challenging for the patients. While effective, they have limitations, prompting a search for alternative treatments, there is a growing interest in exploring natural products notably flavonoids as potential sources of novel MAO-B inhibitors. In line with that, the present review focuses on natural flavonoids of plant origin that hold promise as potential candidates for the development of novel MAO-B inhibitors. The discussion encompasses both invitro and invivo studies, shedding light on their potential therapeutic applications. Furthermore, this review underscores the significance of exploring natural products as valuable reservoirs of MAO-B inhibitors, offering new avenues for drug development and addressing the pressing need for improved treatments in PD-like pathological conditions. The authors of this review majorly explore the neuroprotective potential of natural flavonoids exhibiting notable MAO-B inhibitory activity and additionally multi-targeted approaches in the treatment of PD with clinical evidence and challenges faced in current therapeutic approaches.

Evaluation of (S)-T1 and (S)-T2 ligands targeting α3β4 nAChR as potential nicotine addiction pharmacotherapy.

Substance use disorders (SUDs) represent a significant global health concern, demanding the development of effective pharmacological treatments. To address this, an investigation was conducted to examine the anti-addictive properties of two compounds, (S)-T1 and (S)-T2, which specifically target the α3β4 nicotinic acetylcholine receptor (nAChR). The effects of (S)-T1 and (S)-T2 on nicotine-induced conditioned place preference (CPP), locomotor activity and dopamine levels in particular brain regions associated to addiction were investigated and compared in male C57BL/6N mice. The results demonstrate that neither (S)-T1 nor (S)-T2 induced place conditioning or conditioned place aversion (CPA), suggesting the absence of rewarding or aversive effects. Both compounds significantly attenuated nicotine-induced CPP, with (S)-T1 exhibiting a dose-dependent effect. Furthermore, the co-administration of (S)-T2 (10mg/kg) with nicotine markedly reduced locomotor activity compared to nicotine treatment alone. Additionally, dopamine analysis revealed that nicotine increased dopamine levels in the nucleus accumbens (NAc) and dorsal striatum, whereas the co-administration of (S)-T1 (1, 3, and 10mg/kg) and (S)-T2 (10mg/kg) significantly decreased dopamine levels in these brain regions. No significant effects were observed in the prefrontal cortex (PFC). These findings suggest that (S)-T1 and (S)-T2 hold promise for treating nicotine addiction by attenuating nicotine-induced CPP and modulating dopamine release in key reward-related brain regions. Further research is needed to gain insights into the underlying mechanisms behind their anti-addictive effects and substantiate their potential for treating nicotine addiction.

GDNF improves the cognitive ability of PD mice by promoting glycosylation and membrane distribution of DAT

The core of clinic treatment of Parkinson's disease (PD) is to enhance dopamine (DA) signaling within the brain. The regulation of dopamine transporter (DAT) is integral to this process. This study aims to explore the regulatory mechanism of glial cell line-derived neurotrophic factor (GDNF) on DAT, thereby gaining a profound understanding its potential value in treating PD. In this study, we investigated the effects of GDNF on both cellular and mouse models of PD, including the glycosylation and membrane transport of DAT detected by immunofluorescence and immunoblotting, DA signal measured by neurotransmitter fiber imaging technology, Golgi morphology observed by electron microscopic, as well as cognitive ability assessed by behavior tests. This study revealed that in animal trials, MPTP-induced Parkinson's Disease (PD) mice exhibited a marked decline in cognitive function. Utilizing ELISA and neurotransmitter fiber imaging techniques, we observed a decrease in dopamine levels and a significant reduction in the intensity of dopamine signal release in the Prefrontal Cortex (PFC) of PD mice induced by MPTP. Intriguingly, these alterations were reversed by Glial Cell Line-Derived Neurotrophic Factor (GDNF). In cellular experiments, following MPP + intervention, there was a decrease in Gly-DAT modification in both the cell membrane and cytoplasm, coupled with an increase in Nongly-DAT expression and aggregation of DAT within the cytoplasm. Conversely, GDNF augmented DAT glycosylation and facilitated its membrane transport in damaged dopaminergic neurons, concurrently reversing the effects of GRASP65 depletion and Golgi fragmentation, thereby reducing the accumulation of DAT in the Golgi apparatus. Furthermore, overexpression of GRASP65 enhanced DAT transport in PD cells and mice, while suppression of GRASP65 attenuated the efficacy of GDNF on DAT. Additionally, GDNF potentiated the reutilization of neurotransmitters by the PFC presynaptic membrane, boosting the effective release of dopamine following a single electrical stimulation, ultimately ameliorating the cognitive impairments in PD mice.Therefore, we propose that GDNF enhances the glycosylation and membrane trafficking of DAT by facilitating the re-aggregation of the Golgi apparatus, thereby amplifying the utilization of DA signals. This ultimately leads to the improvement of cognitive abilities in PD mouse models. Our study illuminates, from a novel angle, the beneficial role of GDNF in augmenting DA utilization and cognitive function in PD, providing fresh insights into its therapeutic potential.

Controlling the pathological activity of parkinsonian basal nuclei with the basal ganglia network model under light stimulation in the three-state, four-state channelrhodopsin, and three-state halorhodopsin optogenetic models

Background. Parkinson’s disease (PD) is a neurological disorder caused by the dysfunction of the basal nuclei, especially the substantia nigra, and a decrease in dopamine levels in the neural circuits of this part. In this paper, to investigate the effects of optogenetic stimulation on parkinsonian nervous systems, a complete model of basal ganglia (BG, including subthalamic nucleus [STN], globus pallidus interna [GPi], globus pallidus externa [GPe], and thalamus [TH] neurons) was first selected to simulate the neurons of the basal nuclei and was developed for PD using three- and four-state optogenetic stimulation. Methods. For this purpose, channelrhodopsin-2 (ChETA), ChRwt, and halorhodopsin (NpHR) opsins were evaluated in three-state and four-state stimulation modes, and different stimulation conditions according to different parameters in the BG model were taken into consideration. Results. To verify the developed model, the obtained results were compared with the results of experimental studies. The amount of compliance for different stimulation conditions and various genes underwent investigation. The value of the error index was calculated to evaluate the performance of the BG model for each gene in three- and four-state stimulation conditions with different values of basic parameters, and the stimulation conditions that created the error index equal to zero were introduced as optimal conditions. Based on the results, the frequencies of 20 Hz and 200 Hz in the four-state ChRwt model and the frequency of 80 Hz in the three-state ChETA model have been suggested as optimal genes, frequencies, and models. Conclusion. The response of GPe neurons was consistent with the experimental results, and the response of other neurons was also similar to the response of GPe neurons. In optimal conditions, STN and GPe neurons could provide excitatory input and appropriate inhibitory input to GPi, respectively, and GPi neurons could provide appropriate inhibitory input to TH, and as a result, its function improved and the pathological effects of PD disappeared. Practical Implications. In this research, it has been attempted to improve the function of the basal nuclei of the brain by using optogenetic stimulation and the elimination of the pathological symptoms of PD.

Mitigating gut microbial degradation of levodopa and enhancing brain dopamine: Implications in Parkinson’s disease

Parkinson’s disease is managed using levodopa; however, as Parkinson’s disease progresses, patients require increased doses of levodopa, which can cause undesirable side effects. Additionally, the oral bioavailability of levodopa decreases in Parkinson’s disease patients due to the increased metabolism of levodopa to dopamine by gut bacteria, Enterococcus faecalis, resulting in decreased neuronal uptake and dopamine formation. Parkinson’s disease patients have varying levels of these bacteria. Thus, decreasing bacterial metabolism is a promising therapeutic approach to enhance the bioavailability of levodopa in the brain. In this work, we show that Mito-ortho-HNK, formed by modification of a naturally occurring molecule, honokiol, conjugated to a triphenylphosphonium moiety, mitigates the metabolism of levodopa—alone or combined with carbidopa—to dopamine. Mito-ortho-HNK suppresses the growth of E. faecalis, decreases dopamine levels in the gut, and increases dopamine levels in the brain. Mitigating the gut bacterial metabolism of levodopa as shown here could enhance its efficacy.

Ocular disorders in Parkinson’s disease: A review

Parkinson’s disease (PD) is a common degenerative disorder characterized by decreased dopamine levels from damage to the substantia nigra causing classic motor deficits. Several ocular deficits have been recognized in association with PD such as oculomotor disturbances and diplopia, glaucoma and visual field loss, dry eye disease, color and contrast impairment, visual hallucinations, and visuospatial and visuoperceptual impairments. These disorders remain underreported, underrecognized, and poorly understood. Patients with PD are largely dependent on visual cues for compensating the motor deficits. Hence, early recognition and timely management of the above ocular disorders can lead to greater patient safety, independence, and a better quality of life.

CGRP causes anxiety via HP1γ–KLF11–MAOB pathway and dopamine in the dorsal hippocampus

Calcitonin gene-related peptide (CGRP) is a neuropeptide that causes anxiety behavior; however, the underlying mechanisms remain unclear. We found that CGRP modulates anxiety behavior by epigenetically regulating the HP1γ-KLF-11-MAOB pathway and depleting dopamine in the dorsal hippocampus. Intracerebroventricular administration of CGRP (0.5 nmol) elicited anxiety-like behaviors in open field, hole-board, and plus-maze tests. Additionally, we observed an increase in monoamine oxidase B (MAOB) levels and a concurrent decrease in dopamine levels in the dorsal hippocampus of mice following CGRP administration. Moreover, CGRP increased abundance the transcriptional regulator of MAOB, Krüppel-like factor 11 (KLF11), and increased levels of phosphorylated heterochromatin protein (p-HP1γ), which is involved in gene silencing, by methylating histone H3 in the dorsal hippocampus. Chromatin immunoprecipitation assay showed that HP1γ was recruited to the Klf11 enhancer by CGRP. Furthermore, infusion of CGRP (1 nmol) into the dorsal hippocampus significantly increased MAOB expression as well as anxiety-like behaviors, which were suppressed by the pharmacological inhibition or knockdown of MAOB. Together, these findings suggest that CGRP reduces dopamine levels and induces anxiety-like behavior through epigenetic regulation in the dorsal hippocampus.

Research progress on the roles of dopamine and dopamine receptors in digestive system diseases.

Dopamine (DA) is a neurotransmitter synthesized in the human body that acts on multiple organs throughout the body, reaching them through the blood circulation. Neurotransmitters are special molecules that act as messengers by binding to receptors at chemical synapses between neurons. As ligands, they mainly bind to corresponding receptors on central or peripheral tissue cells. Signalling through chemical synapses is involved in regulating the activities of various body systems. Lack of DA or a decrease in DA levels in the brain can lead to serious diseases such as Parkinson's disease, schizophrenia, addiction and attention deficit disorder. It is widely recognized that DA is closely related to neurological diseases. As research on the roles of brain-gut peptides in human physiology and pathology has deepened in recent years, the regulatory role of neurotransmitters in digestive system diseases has gradually attracted researchers' attention, and research on DA has expanded to the field of digestive system diseases. This review mainly elaborates on the research progress on the roles of DA and DRs related to digestive system diseases. Starting from the biochemical and pharmacological properties of DA and DRs, it discusses the therapeutic value of DA- and DR-related drugs for digestive system diseases.

Transcriptomic effects of paternal cocaine-seeking on the reward circuitry of male offspring

It has been previously established that paternal development of a strong incentive motivation for cocaine can predispose offspring to develop high cocaine-seeking behavior, as opposed to sole exposure to the drug that results in drug resistance in offspring. However, the adaptive changes of the reward circuitry have not been fully elucidated. To infer the key nuclei and possible hub genes that determine susceptibility to addiction in offspring, rats were randomly assigned to three groups, cocaine self-administration (CSA), yoked administration (Yoke), and saline self-administration (SSA), and used to generate F1. We conducted a comprehensive transcriptomic analysis of the male F1 offspring across seven relevant brain regions, both under drug-naïve conditions and after cocaine self-administration. Pairwise differentially expressed gene analysis revealed that the orbitofrontal cortex (OFC) exhibited more pronounced transcriptomic changes in response to cocaine exposure, while the dorsal hippocampus (dHip), dorsal striatum (dStr), and ventral tegmental area (VTA) exhibited changes that were more closely associated with the paternal voluntary cocaine-seeking behavior. Consistently, these nuclei showed decreased dopamine levels, elevated neuronal activation, and elevated between-nuclei correlations, indicating dopamine-centered rewiring of the midbrain circuit in the CSA offspring. To determine if possible regulatory cascades exist that drive the expression changes, we constructed co-expression networks induced by paternal drug addiction and identified three key clusters, primarily driven by transcriptional factors such as MYT1L, POU3F4, and NEUROD6, leading to changes of genes regulating axonogenesis, synapse organization, and membrane potential, respectively. Collectively, our data highlight vulnerable neurocircuitry and novel regulatory candidates with therapeutic potential for disrupting the transgenerational inheritance of vulnerability to cocaine addiction.

HIV-1 Tat and morphine interactions dynamically shift striatal monoamine levels and exploratory behaviors over time.

Despite the advent of combination anti-retroviral therapy (cART), nearly half of people infected with HIV treated with cART still exhibit HIV-associated neurocognitive disorders (HAND). HAND can be worsened by co-morbid opioid use disorder. The basal ganglia are particularly vulnerable to HIV-1 and exhibit higher viral loads and more severe pathology, which can be exacerbated by co-exposure to opioids. Evidence suggests that dopaminergic neurotransmission is disrupted by HIV exposure, however, little is known about whether co-exposure to opioids may alter neurotransmitter levels in the striatum and if this in turn influences behavior. Therefore, we assayed motor, anxiety-like, novelty-seeking, exploratory, and social behaviors, and levels of monoamines and their metabolites following 2 weeks and 2 months of Tat and/or morphine exposure in transgenic mice. Morphine decreased dopamine levels, but significantly elevated norepinephrine, the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid, which typically correlated with increased locomotor behavior. The combination of Tat and morphine altered dopamine, DOPAC, and HVA concentrations differently depending on the neurotransmitter/metabolite and duration of exposure but did not affect the numbers of tyrosine hydroxylase-positive neurons in the mesencephalon. Tat exposure increased the latency to interact with novel conspecifics, but not other novel objects, suggesting the viral protein inhibits exploratory behavior initiation in a context-dependent manner. By contrast, and consistent with prior findings that opioid misuse can increase novelty-seeking behavior, morphine exposure increased the time spent exploring a novel environment. Finally, Tat and morphine interacted to affect locomotor activity in a time-dependent manner, while grip strength and rotarod performance were unaffected. Together, our results provide novel insight into the unique effects of HIV-1 Tat and morphine on monoamine neurochemistry that may underlie their divergent effects on motor and exploratory behavior.

Early-life perfluorooctanoic acid exposure disrupts the function of dopamine transporter protein with glycosylation changes implicating the links between decreased dopamine levels and disruptive behaviors in larval zebrafish

Exposure to perfluorooctanoic acid (PFOA) during early embryonic development is associated with the increased risk of developmental neurotoxicity and neurobehavioral disorders in children. In our previous study, we demonstrated that exposure to PFOA affected locomotor activity and disrupted dopamine-related gene expression in zebrafish larvae. Consequently, we continue to study the dopaminergic system with a focus on dopamine levels and dopamine's effect on behaviors in relation to PFOA exposure. In the present study, we found a decrease in dopamine levels in larval zebrafish. We studied the dopamine transporter (DAT) protein, which is responsible for regulating dopamine levels through the reuptake of dopamine in neuronal cells. We demonstrated that exposure to PFOA disrupted the glycosylation process of DAT, inhibited its uptake function, and induced endoplasmic reticulum (ER) stress in dopaminergic cells. Besides, we conducted a light-dark preference test on larval zebrafish and observed anxiety/depressive-like behavioral changes following exposure to PFOA. Dopamine is one of the most prominent neurotransmitters that significantly influences human behavior, with low dopamine levels being associated with impairments such as anxiety and depression. The anxiety-like response in zebrafish larvae exposure to PFOA implies the link with the reduced dopamine levels. Taken together, we can deduce that glycosylation changes in DAT lead to dysfunction of DAT to regulate dopamine levels, which in turn alters behavior in larval zebrafish. Therefore, alternation in dopamine levels may play a pivotal role in the development of anxiety/depressive-like behavioral changes induced by PFOA.

Assessment of Serum Prolactin Levels in Patients with Liver Disease: A Cross-sectional Study

Introduction: Prolactin is a hormone released from the anterior pituitary gland under tonic inhibitory control by dopamine. A decrease in dopamine levels is usually observed in decompensated liver disease, which could be due to its inhibition by the increased synthesis of false neurotransmitters. However, the level of serum prolactin in liver disease patients still remains disputed. Aim: To evaluate the serum prolactin levels in patients with liver disease of different aetiologies and compare them with healthy controls. Materials and Methods: The present cross-sectional study was conducted in the Department of Biochemistry from August 2021 to August 2022 at Amrita Institute of Medical Sciences (AIMS), Kochi, Kerala, India. A total of 100 patients with liver disease and 100 age- and gender-matched healthy controls were enrolled in the study. Serum prolactin was estimated using the Electro- Chemiluminescence Immuno Assay (ECLIA) technique. The serum prolactin levels were compared among patients with liver disease of different aetiologies and with healthy controls. Statistical analysis was carried out using the Mann-Whitney U test, Kruskal-Wallis test, and Dun Bonferroni test. Results: The median serum prolactin levels were significantly elevated in the cases {40.61 (29.13-70.24 ng/mL)} compared to the controls {17 (10.95-20.70 ng/mL)}, This p-value is correct as the median levels for cases is {40.61 (29.13-70.24 ng/mL)}. Comparison of prolactin levels showed no statistically significant difference based on the distribution of age and gender. In the present study, prolactin levels were found to be most prominent in patients with fatty liver disease. Conclusion: The serum prolactin level increased significantly in liver disease patients, particularly in patients with fatty liver. Hence, prolactin levels can be used as a useful predictive biomarker for fatty liver.

Purified Serum IgG from a Patient with Anti-IgLON5 Antibody Cause Long-Term Movement Disorders with Impaired Dopaminergic Pathways in Mice.

Background: Anti-IgLON5 disease is a rare autoimmune disease of the central nervous system. It typically manifests as a chronic condition, characterized by cognitive impairments, movement disorders, and sleep disorders. The mechanisms underlying movement disorders in this disease remain poorly understood due to a lack of research. Furthermore, this disease exhibits both neuroimmune and neurodegenerative characteristics. The objective of this study is to explore the underlying mechanisms of movement disorders caused by anti-IgLON5 antibodies for the first time. Methods: Antibodies were purified from the serum of a confirmed patient of anti-IgLON5 disease. The passive transfer animal models were employed, where antibodies were continuously injected into the substantia nigra pars compacta (SNc) of the mouse midbrain using stereotactic injection to explore the mechanism of movement disorder. The effects of anti-IgLON5 antibodies on dopaminergic neurons in the SNc and neurodegeneration were examined through immunohistochemistry. Changes in neurotransmitter levels in the basal ganglia were assessed using high-performance liquid chromatography. Additionally, RNA-seq was employed to identify the differentially expressed genes associated with the short-term and long-term effects of anti-IgLON5 antibody on the SNc. Results: Mice injected with anti-IgLON5 antibodies in the SNc exhibited persistent movement impairments for up to 3 months. One week after antibody injection, the number of TH neurons significantly decreased compared to the control group, accompanied by reduced projection fibers in the basal ganglia and decreased dopamine levels. After 3 months of antibody injection, an increase in phosphorylated Tau was observed in the SNc of the midbrain. Additionally, long-term sustained activation of microglia was detected in the SNc. The differentially expressed genes of long-term effects of IgLON5 antibodies were different from their short-term effects on the SNc. Conclusion: Purified serum IgG from a patient with anti-IgLON5 antibodies can cause long-term movement disorder in mice. The movement disorders appear to be linked to the impaired dopaminergic pathway, and the increased p-Tau showed neurodegenerative changes induced by the anti-IgLON5 antibody.

Catecholamines and Parkinson's disease: tyrosine hydroxylase (TH) over tetrahydrobiopterin (BH4) and GTP cyclohydrolase I (GCH1) to cytokines, neuromelanin, and gene therapy: a historical overview.

The author identified the genes and proteins of human enzymes involved in the biosynthesis of catecholamines (dopamine, norepinephrine, epinephrine) and tetrahydrobiopterin (BH4): tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine β-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), and GTP cyclohydrolase I (GCH1). In Parkinson's disease (PD), the activities and levels of mRNA and protein of all catecholamine-synthesizing enzymes are decreased, especially in dopamine neurons in the substantia nigra. Hereditary GCH1 deficiency results in reductions in the levels of BH4 and the activities of TH, causing decreases in dopamine levels. Severe deficiencies in GCH1 or TH cause severe decreases in dopamine levels leading to severe neurological symptoms, whereas mild decreases in TH activity in mild GCH1 deficiency or in mild TH deficiency result in only modest reductions in dopamine levels and symptoms of DOPA-responsive dystonia (DRD, Segawa disease) or juvenile Parkinsonism. DRD is a treatable disease and small doses of L-DOPA can halt progression. The death of dopamine neurons in PD in the substantia nigra may be related to (i) inflammatory effect of extra neuronal neuromelanin, (ii) inflammatory cytokines which are produced by activated microglia, (iii) decreased levels of BDNF, and/or (iv) increased levels of apoptosis-related factors. This review also discusses progress in gene therapies for the treatment of PD, and of GCH1, TH and AADC deficiencies, by transfection of TH, AADC, and GCH1 via adeno-associated virus (AAV) vectors.

Detection of Parkinson’s disease based on spectrograms of voice recordings and Extreme Learning Machine random weight neural networks

Parkinson’s disease consists in the degeneration of the mesencephalic black substance, affecting the dopaminergic vias. Its causes are varied, including exposure to pesticides, genetic factors and, one of the most influential ones, age. Given the decrease in dopamine levels, the most common symptoms are the appearance of tremors and muscle rigidity. Due to the rigidity of the muscles, the patient has voice alterations which have great potential for non-invasive and early diagnosis of the disease. In addition, considering the low cost of the sound recorder respect to the clinical studies, this approach allows the diagnosis of Parkinson’s disease in a large number of people. Recent works, which present the analysis of voice recordings through Convolutional Neural Networks, show high level of accuracy in the diagnosis of Parkinson’s disease. Convolutional Neural Networks use a Multilayer Neural Network to classify convolutional feature vectors. In order to improve the training time of the classifier, in this paper the use Extreme Learning Machines are proposed. Experiments considering 4 types of spectrograms with AlexNet, VGG-16, SqueezeNet, Inception V3 and ResNet-50 Convolutional Neural Networks models. In the experiments, hit rate, training and testing time, sensitivity and the specificity indicators of all the neural architectures involved in the work are objectively compared. It is shown that the Extreme Learning Machine have a high level of accuracy in the diagnosis of Parkinson’s disease but with reduced training time.

Effects of chronic irisin treatment on brain monoamine levels in the hypothalamic and subcortical nuclei of adult male and female rats: An HPLC-ECD study

Monoaminergic systems are known to be involved in the pathophysiology of neuropsychiatric disorders and vegetative functions due to their established influence on hypothalamic and subcortical areas. These systems can be modulated by lifestyle factors, especially exercise, which is known to produce several beneficial effects on reproduction, brain health, and mental disorders. The fact that exercise is sensed by the brain shows that muscle-stimulated secretion of myokines allows direct crosstalk between the muscles and the brain. One of such exercise-induced beneficial effects on the brain is exhibited by irisin—a recently discovered PGC-1α-dependent adipo-myokine mainly secreted from skeletal muscle during exercise. Thus, we hypothesized that irisin may affect central monoamine levels and thus play an important role in the muscle–brain endocrine loop. To test this assertion, for 10 weeks, vehicle (deionized water) or 100 ng/kg irisin was injected intraperitoneally once a day to 12 male and 12 female rats after which the levels of monoamines and their metabolites were determined by HPLC-ECD. In the hypothalamic nuclei, irisin significantly decreased dopamine (DA) metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) (p < 0.05), DOPAC/DA ratio (p < 0.01) and noradrenaline (NA, p < 0.05) levels in the anteroventral periventricular nucleus (AVPV), and DOPAC and NA levels in the medial preoptic area (mPOA) (p < 0.05), having a crucial role in reproduction and sexual motivation, respectively. On the other hand, irisin significantly increased DOPAC levels in the lateral hypothalamic area (LHA) (p < 0.05), which acts as a hunger center, while it significantly decreased the levels of DA, NA, and its metabolite 3,4-dihydroxyphenylglycol (DHPG) in the ventromedial hypothalamic nucleus (VMH) as a known satiety center (p < 0.05). In nucleus accumbens (NaC), irisin significantly reduced 5-hydroxyindoleacetic acid (5-HIAA) levels (p < 0.05), which are implicated in autism spectrum disorder (ASD) physiopathology. It also significantly increased DA levels in this area, thus exhibiting positive effects on depression and sexual dysfunction in men. On the other hand, it significantly decreased serotonin (5-HT) (p < 0.01) and its metabolite 5-HIAA levels in the medial amygdala (MeA) (p < 0.05), indicating that it may play a role in social behaviors. Moreover, it significantly attenuated NA levels in the same subcortical area (p < 0.01), which is directly involved in stress-induced activation of the central noradrenergic system. These findings demonstrate for the first time that irisin induces significant changes in monoamine levels in many hypothalamic nuclei involved in feeding behavior and vegetative functions, as well as in subcortical nuclei related to neuropsychiatric disorders.

50-kHz ultrasonic vocalizations do not signal social anhedonia in transgenic DISC1 rats.

Patients diagnosed with neuropsychiatric disorders, such as autism and schizophrenia, suffer from disorganized speech. The disrupted-in-schizophrenia 1 (DISC1) protein pathway is considered a risk factor for the development of several psychiatric disorders and plays an important role in the dysregulation of dopamine (DA), which in turn plays an important role in the regulation of ultrasonic vocalizations (USVs) in rats. Moreover, the DISC1 protein pathway has been identified as a cause of social anhedonia, that is, a decrease in the drive for social interactions. USVs transmit specific affective information to other rats, with 50-kHz calls indicating a positive affective state in rats. Dysregulation of the dopaminergic system impacts the qualitative and quantitative features of USVs, such as duration, peak frequency, and the call rate. In this study, we thus used a well-established transgenic DISC1 (tgDISC1) rat line to investigate whether the neural (decreased DA levels in the dorsal striatum, amygdala, and hippocampus (HPC)) and behavioral (social anhedonia) features of tgDISC1 rats could be manifested through the modulation of their 50-kHz USVs. Analyses of three features (call rate, duration, and peak frequency) of all 50-kHz revealed no significant differences between groups, suggesting decreased DA levels in the dorsal striatum and amygdala, and HPC may affect social interaction but leave 50-kHz USV production intact.

The Role of Microbes for Triggering Neurological Diseases

Neurological diseases have become a focus of study due to the aging of society. This research analysis different diseases including Parkinson’s disease and Alzheimer’s disease, where the microbes that cause or contribute to their development of symptoms. This includes what causes the diseases’ symptoms and how microbes contribute to those symptoms. The symptoms of Alzheimer’s disease are largely connected with neuroinflammation and amyloid build-up in the brain. Spirochetes are known to produce neuroinflammation. Chlamydia pneumoniae has been shown to increase in the patient’s brain, but this is not supported by all research. Porphyromonas gingivalis infection is connected to neurodegeneration. Although exercise may aid in the slowing of the development of Alzheimer’s disease, the underlying mechanisms are uncertain. Parkinson’s disease is mostly caused by neuron death, which leads in decreased dopamine levels. This is due to DJ-1, which has been related to cell cycle checkpoint disruption. Repeated infections with Citrobacter rodentium cause Parkinson's-like motor symptoms as well as the mice lose their dopaminergic neuronal axonal varicosities. Proteus mirabilis causes neuronal loss. Lactobacillus and inflammation have been related in stroke. Other than the microorganisms discussed in this article, there are many more that influence the brain and contribute to diseases. More study could look into ways to reduce the presence of those microorganisms and reverse the damage they cause.

Studying the Brain Monoaminergic Systems and Neurotrophic Factors in Minipigs with High and Low Tolerance to the Presence of Human

Here, we present the first evidence for brain adaptation in pigs tolerant to the human presence, as a behavioral trait favoring domestication. The study was carried out on minipiglets from population bred at the Institute of Cytology and Genetics (Novosibirsk, Russia). We compared the behavior, metabolism of monoaminergic neurotransmitter systems, and functional activity of the hypothalamic-pituitary-adrenal system, as well as neurotrophic markers in the brain of minipigs differing by tolerance to human presence (HT and LT – high and low tolerance). The piglets did not differ in the levels of activity in the open field test. However, the concentration of cortisol plasma was significantly higher in minipigs with a low tolerance to the presence of humans. Moreover, LT minipigs demonstrated a decreased level of serotonin in the hypothalamus and augmented levels of serotonin and its metabolite 5-HIAA in the substantia nigra as compared to HT animals. In addition, LT minipigs showed increased content of dopamine and its metabolite DOPAC in the substantia nigra and decreased dopamine level in the striatum as well as reduced content of noradrenaline in the hippocampus. Increased mRNA levels of two markers of the serotonin system – TPH2 and HTR7 genes – in the raphe nuclei and in the prefrontal cortex, respectively, were associated in minipigs with a low tolerance to human presence. However, the expression of genes regulating a dopaminergic system (COMT, DRD1, and DRD2) in HT and LT animal groups varied depending on brain structure. In addition, a decrease in the expression of genes encoding BDNF (brain-derived neurotrophic factor) and GDNF (glial cell line-derived neurotrophic factor) was revealed in LT minipigs. The results may contribute to our understanding of the initial stage of domestication in pigs.