Lower Dopamine Levels Research Articles

Irritable bowel syndrome phenotypes: leading factors of genetics and epigenetics, mechanisms of formation

To develop individualized approaches to the treatment of irritable bowel syndrome (IBS) based on the interaction of genetic and epigenetic factors, to characterize the phenotypes of the disease. According to the formulated concept of the authors, from the cohort of patients with IBS, subgroups were distinguished - "post-infectious IBS" (n=45), "IBS in overweight and obese people" (n=49), "comorbid IBS" (n=75) and "essential IBS" (n=51). In each subgroup the prevalence of candidate gene polymorphisms associated with IBS (COMT, SLC6A4, FTO), nutritional habits, levels of anxiety and depression, secretion of cortisol, serotonin, dopamine and zonulin levels in feces were studied. Patients with "post-infectious IBS" are characterized by the carriage of the S allele of the SLC6A4 gene, the val/val genotype of the COMT gene, the prevalence of diarrhea, a high level of anxiety and frequent refusal of milk and dairy products. The phenotype "IBS in overweight and obese individuals" is characterized by L/L genotypes of the SLC6A4 gene, met/met of the COMT gene and A/A of the FTO gene, constipation, low plasma dopamine levels, signs of depression, frequent episodes of overeating, addiction to fatty and sweet foods, excessive consumption of sugar, lack of vegetables in the diet. The "comorbid IBS phenotype" is characterized by more frequent detection of the val/val genotype of the COMT gene and the carriage of the S allele of the SLC6A4 gene, clinically pronounced anxiety and depression, early onset of the disease, severe course, significant food restrictions and significant increase in epithelial permeability. With the "essential phenotype", there are no bright stigmas of the disease; it is not possible to identify distinctive genetic and epigenetic factors, as well as the leading pathogenetic mechanism. The analysis of genetic and epigenetic factors, the leading mechanisms of the formation and course of IBS allows us to identify additional (except for "postinfectious") phenotypes of the disease: "IBS in overweight and obese people", "comorbid" and "essential".

Computational models of dopamine release measured by fast scan cyclic voltammetry in vivo.

Dopamine neurotransmission in the striatum is central to many normal and disease functions. Ventral midbrain dopamine neurons exhibit ongoing tonic firing that produces low extrasynaptic levels of dopamine below the detection of conventional extrasynaptic cyclic voltammetry (∼10-20 nanomolar), with superimposed bursts that can saturate the dopamine uptake transporter and produce transient micromolar concentrations. The bursts are known to lead to marked presynaptic plasticity via multiple mechanisms, but analysis methods for these kinetic parameters are limited. To provide a deeper understanding of the mechanics of the modulation of dopamine neurotransmission by physiological, genetic, and pharmacological means, we present three computational models of dopamine release with different levels of spatiotemporal complexity to analyze in vivo fast-scan cyclic voltammetry recordings from the dorsal striatum of mice. The models accurately fit to cyclic voltammetry data and provide estimates of presynaptic dopamine facilitation/depression kinetics and dopamine transporter reuptake kinetics, and we used the models to analyze the role of synuclein proteins in neurotransmission. The models' results support recent findings linking the presynaptic protein α-synuclein to the short-term facilitation and long-term depression of dopamine release, as well as reveal a new role for β-synuclein and/or γ-synuclein in the long-term regulation of dopamine reuptake.

Active vs passive novelty-related strategies: Sex differences in exploratory behaviour and monoaminergic systems

Sex differences are apparent in numerous behavioural characteristics. In order to compare and characterise male and female variability of exploratory behaviour, 365 male and 401 female rats were assessed in a task where a bimodal response distribution had previously been established in males. Female rats had significantly higher exploratory activity, and presented normal distribution of the behaviour, very differently from the bimodal distribution of males. No major effect of litter or oestrous cycle was detected. Several differences between male and female rats were found in monoamine metabolism measured ex vivo. Male rats had lower levels of dopamine (DA) in frontal cortex, and higher levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in raphe area; higher levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in dorsal striatum but lower levels of 5-HT and 5-HIAA in locus coeruleus area, 5-HIAA levels were also lower in hippocampus as compared to females. Males had higher noradrenaline (NA) levels in hippocampus and lower normetanephrine (NMN) levels in striatum, in both brain regions male animals had lower NMN/NA ratio. No sex difference was found in accumbens. The only brain region with an interaction between sex and the expression of exploratory activity was raphe: Here 5-HT levels were lower, and DOPAC levels and DOPAC/DA and 5-HIAA/5-HT ratios higher in low exploring male but not female rats. Conclusively, female rats not only display higher levels of exploration but the population distribution of this behaviour is distinct; this may be related to differences in the monoaminergic systems between female and male animals.

Chronic Pain And Levodopa Therapy in Parkinson’s Disease Patients

Background: Pain is a frequent non-motor symptom in patients with Parkinson’s disease (PD) and appears to be related to low levels of dopamine. This study describes the characteristics of chronic pain in a group of PD patients undergoing levodopa therapy. Methods: This was a cross-sectional study. The pain was assessed in 21 selected PD patients with chronic pain using several scales and instruments. Changes in pain response from levodopa use (wearing-off phenomenon) were monitored. Results: The most prevalent type of pain was nociceptive (71.4%), musculoskeletal and dystonic, but neuropathic pain accounted for the highest pain score according to the Parkinson’s Disease Pain Classification System (45.5±30.08). Patients with neuropathic, nociplastic, or nociceptive pain upon wearing-off were those who responded to levodopa (p=0.999). According to the McGill questionnaire, patients with pain upon wearing-off had higher scores in the affective/motivational dimension (p=0.022). Conclusion: Using a new pain classification and scoring tool, this study corroborates a good response to levodopa in PD-related pain.

Abstract 13157: Workplace Culture and Biomarkers of Sympathetic Activation

Workplace environment can impact health, but most research has focused on toxic chemicals. Recently, workplace culture—experiences, values, and behaviors unique to a workplace—is studied for its impact on overall health risk; however, connections with robust biologic markers of health remain to be established. Therefore, we examine associations between work environment and urinary levels of catecholamines and their metabolites as biomarkers of sympathetic activation. In 2018-19, we recruited participants (n=219) from an ongoing CV risk cohort to investigate workplace culture, overall well-being, and stress. Participants completed 7 questionnaires. Clean catch urine samples were used to measure catecholamines and their metabolites. To estimate associations between work and health scales and log or logit-transformed outcomes we used Pearson correlation and linear regression models adjusting for demographics and creatinine. Participants reporting higher well-being had lower levels of dopamine (DA) ( r = -0.28), serotonin (5HT) ( r = -0.17), and 3-methoxytyramine (3MT) ( r = -0.31), a product of dopamine breakdown. Participants reporting a more engaged workplace had lower levels of DA ( r = -0.20) and 3MT ( r = -0.22). Those reporting more positive workplace culture had lower levels of DA ( r = -0.17) and 3MT ( r = -0.26) and higher levels of norepinephrine ( r = 0.19) and 5-hydroxyindole-3-acetic acid (HIAA) ( r = 0.22). When participants identified more workplace isolation, they had higher levels of DA ( r = 0.19) and 3MT ( r = 0.19). Positive workplace culture was correlated with lower levels of DA ( r = -0.22) and 3MT ( r = -0.28) and higher levels of HIAA ( r = 0.22) and homovanillic acid ( r = 0.20). Given high correlations between catecholamines, we used 3MT for linear regression. In fully adjusted models we found in more positive work cultures, levels of 3MT remained significantly lower (β = -0.065 ±0.025, p = 0.01), accounting for 23% of the variance, and a significant positive association between workplace isolation and 3MT (β= 0.064 ±0.030, p = 0.04), accounting for 22% of the variance with 3MT, which may reflect greater dopamine degradation. These findings suggest an important relationship between how we work and sympathetic nervous system activity.

Time course of plasticity-related alterations following the first exposure to amphetamine in juvenile rats

In vulnerable consumers, the first drug exposure induces various neurobehavioral adaptations that may represent the starting point toward addiction. Elucidating the neuroplastic mechanisms underlying that first rewarding experience would contribute to understanding the transition from recreational to compulsive drug use. In a preclinical model with juvenile rats, we analyzed the time-dependent fluctuations in the expression of neuroplasticity-related genes like the brain-derived neurotrophic factor (BDNF), its tropomyosin receptor kinase B (TrkB), the cAMP response element-binding protein (CREB), the microRNA-132, the Rho GTPase-activating protein 32 (p250GAP), the corticotropin-releasing factor (CRF), and the neurotransmitters contents in the nucleus accumbens (NAc) and the dorsal striatum (DS) 45, 90, and 180 min after an amphetamine (AMPH) injection. As expected, AMPH altered the concentration of norepinephrine, dopamine, DOPAC, and serotonin in a region- and time-dependent manner. Regarding gene expression, AMPH at 45 min upregulated BDNF and primiR-132 expression in NAc and downregulated TrkB expression in DS. At 90 min, AMPH upregulated TrkB, CREB, p250GAP, and primiR-132 expression in NAc and BDNF, primiR-132, and CRF in DS. At 180 min, only BNDF in NAc continued to be upregulated by AMPH. Based on the levels of AMPH-induced hyperactivity, we classified the rats as low and high AMPH responders. High AMPH responders characterized by overexpressing BDNF, CREB, p250GAP, and CRF in NAc and by showing lower levels of dopamine and serotonin metabolites and turnovers in both regions. Our findings demonstrated that a single AMPH administration is enough to induce neuroplastic adaptations, especially in the NAc of prone rats.

Assessing the Neurotoxicity of a Sub-Optimal Dose of Rotenone in Zebrafish (Danio rerio) and the Possible Neuroactive Potential of Valproic Acid, Combination of Levodopa and Carbidopa, and Lactic Acid Bacteria Strains.

Parkinson’s disease (PD) is an enigmatic neurodegenerative disorder that is currently the subject of extensive research approaches aiming at deepening the understanding of its etiopathophysiology. Recent data suggest that distinct compounds used either as anticonvulsants or agents usually used as dopaminergic agonists or supplements consisting of live active lactic acid bacteria strains might alleviate and improve PD-related phenotypes. This is why we aimed to elucidate how the administration of rotenone (ROT) disrupts homeostasis and the possible neuroactive potential of valproic acid (VPA), antiparkinsonian agents (levodopa and carbidopa – LEV+CARB), and a mixture of six Lactobacillus and three Bifidobacterium species (PROBIO) might re-establish the optimal internal parameters. ROT causes significant changes in the central nervous system (CNS), notably reduced neurogenesis and angiogenesis, by triggering apoptosis, reflected by the increased expression of PARKIN and PINK1 gene(s), low brain dopamine (DA) levels, and as opposed to LRRK2 and SNCA compared with healthy zebrafish. VPA, LEV/CARB, and PROBIO sustain neurogenesis and angiogenesis, manifesting a neuroprotective role in diminishing the effect of ROT in zebrafish. Interestingly, none of the tested compounds influenced oxidative stress (OS), as reflected by the level of malondialdehyde (MDA) level and superoxide dismutase (SOD) enzymatic activity revealed in non-ROT-exposed zebrafish. Overall, the selected concentrations were enough to trigger particular behavioral patterns as reflected by our parameters of interest (swimming distance (mm), velocity (mm/s), and freezing episodes (s)), but sequential testing is mandatory to decipher whether they exert an inhibitory role following ROT exposure. In this way, we further offer data into how ROT may trigger a PD-related phenotype and the possible beneficial role of VPA, LEV+CARB, and PROBIO in re-establishing homeostasis in Danio rerio.

ADHD AND SUBSTANCE USE DISORDER: EMERGING CONCEPTS

ADHD is an independent risk factor for substance use disorder (SUD); however, the relationship between these 2 conditions is complex. Research has pointed to shared neurochemical characteristics (eg, low central nervous system dopamine levels), compromised functioning of the brain reward system, and the presence of inhibitory control deficits in both ADHD and SUD. This Symposium will report new findings from observational, experimental, and treatment studies examining different aspects of the ADHD-SUD relationship.

Workplace Culture and Biomarkers of Health Risk.

Workplace culture has been studied for impact on health risk; however, connections with robust biologic markers of health remain to be established. We examined associations between the work environment and urinary levels of catecholamines and their metabolites as biomarkers of sympathetic nervous system activity, indicative of stress. We recruited participants (n = 219; 2018–2019) from a cardiovascular risk cohort to investigate workplace culture, well-being, and stress. Participants completed seven questionnaires. Urine samples were used to measure catecholamines and their metabolites by LC/MS/MS. Pearson correlation and linear regression models were used after adjusting for demographics and creatinine. Participants reporting higher well-being had lower urinary levels of dopamine, serotonin, and 3-methoxytyramine. Participants reporting a more engaged and more positive workplace had lower levels of dopamine and 3-methoxytyramine. Reported workplace isolation was correlated with higher levels of dopamine and 3-methoxytyramine. Given correlations between catecholamines, we used 3-methoxytyramine for linear regression. In fully adjusted models, in environments with a more positive culture, levels of 3-methoxytyramine remained lower (β = −0.065 ± 0.025, p = 0.01) and indicated a positive association between workplace isolation and 3-methoxytyramine (β = 0.064 ± 0.030, p = 0.04). These findings are consistent with an important relationship between workplace environment and sympathetic nervous system activity.

“[S]ome vicious mole of nature”: Hamlet’s Erratic Behaviour and Brain Neurotransmitter Imbalance

The aim of this paper is to investigate, from a neuroscientific perspective, the complex but still unravelled mystery of Hamlet’s inconsistent conduct in Shakespeare’s classic tragedy. Adopting the ‘medical diagnosis’ method, the paper contends that such manifestations of Hamlet’s eccentric comportment as depression, social isolation, impulsiveness, sleep disorder, aversion to women, and procrastination, are all salient symptoms of low levels of dopamine, a vital brain neurotransmitter responsible for reward and motivation. The paper concludes that ‘dopamine deficiency’ in Hamlet’s brain has a devastating impact on his mood and outlook on life. It aggravates his depression, adversely affects his disposition, focus, cognition, and motivation and subsequently deprives him of the incentive to act. The significance of this study is that it identifies the reason for Hamlet’s hesitation, enhances understanding of the play and enriches representations of the leading role in the play on stage. Shakespeare portrays Hamlet as severely afflicted with such an intricate neural illness (not identified in Elizabethan England then), expertly dramatizing the devastating impact on his protagonist of the acute clash between will and inability. Hamlet’s hamartia is, consequently, not a fault of his making, not a commonplace Aristotelian tragic error of judgment, or a psychological personality flaw, but – as Hamlet intuitively prophesies – a birth defect, the result of ‘some vicious mole of nature

Correlation of catecholamine content and clinical influencing factors in depression among psoriasis patients: a case-control study

ObjectiveOur study sought to investigate the clinical influencing factors of psoriasis patients with depression, and analyze whether the content of monoamine neurotransmitters in plasma was correlated with depression incidence among psoriasis patients.MethodsNinety patients with psoriasis and 40 healthy volunteers (aged from18 to 60) were recruited and interviewed with a piloted questionnaire in both groups to obtain relevant information. The catecholamine in plasma from the two groups was analyzed by radioimmunoassay. The data were analyzed by SPSS statistical software.ResultsThe mean Hamilton Depression Scale (HAMD) and mean Athens Insomnia Scale (AIS) scores of the psoriasis patients were higher than the control group. Dopamine content in the plasma was lower (comparing psoriasis patients without depression and the control group, and was negatively correlated with HAMD, AIS, and Psoriasis Area and Severity Index (PASI) scores in the psoriasis patients with depression. There was no significant difference in the epinephrine and norepinephrine contents in all groups. PASI scores were positively correlated with HAMD scores in psoriasis patients. The low dopamine content, Dermatology Life Quality Index, and high PASI scores were the risk factors for depression among the psoriasis patients.ConclusionPsoriasis patients have a significantly higher risk of depression than healthy people, and higher PASI scores were linked to a higher incidence of depression. The dopamine levels of patients were influenced by both psoriasis and depression. The risk factors for depression in psoriasis patients are low dopamine levels in the plasma, severe skin lesions, and lower quality of life.

Commentary: Curbing myopia progression: The way forward.

Myopia, why the sudden hullabaloo around it? As we all know myopia is an eye disease that has become more prevalent in recent years and is expected to affect nearly half of the world’s population in the future.[12] The authors of the article have very well summarized the older and newer concepts of this soaring disease, the knowledge of which each and every ophthalmologist must have in order to treat his/her patients better. Gone are the days when myopia was treated with just spectacles and its complications were managed as and when it occurred. It’s now time to detect the disease early, slow down the progression and thereby reduce the occurrence of its sight-threatening complications. We all know that myopia is a heritable disease. It must be kept in mind that if one of the parents is a myope, it doubles the risk of myopia in the child and if both parents are myopes there is six-fold increased risk of myopia in the child. Parental myopia[3] is not only a risk factor for developing myopia but is also a risk factor for progressive myopia. Hence, children born to myopes should be screened at regular intervals and watched for any progression. The other important consideration is of pre-myopes who have an increased likelihood of developing myopia, more commonly if there is parental myopia. Pre-myopia,[4] as defined by the IMI, is a refractive state of the eye of ≤ +0.75 D and > −0.5 D in children after cycloplegic refraction with a combination of risk factors. Keeping a closer watch, frequent follow-up and early intervention in pre-myopes may be the need of the hour as well. As rightly said by the authors, there is no fixed guideline for management of myopia and its progression. We have been following this algorithm at our institute. This algorithm was designed based on the recent studies that have investigated the effectiveness of the various treatment modalities for different grades of myopia. In addition to these treatment options, emphasis should be laid on lifestyle changes as most of the children nowadays are indoors due to which there has been an increase in screen time, lack of exposure to sunlight and excessive near activity in many other forms like reading, etc. Supporting this statement is the study by Muthu et al.[5] which stated that during the phase of COVID-19 pandemic lockdown, wherein children were confined to their houses, there was a significant increase in the number of myopes. Hence, children must be encouraged a few hours of outdoor activity (≥2 hours daily) and maintain appropriate distance of 14 inches and posture while doing any near activity. Also, in those children who are voracious readers, constant near activity can also be a risk factor to progression, and hence, they need to follow the 20–20–20 rule (to take regular breaks after 20 minutes of continuous reading by looking at a distance of 20 feet for 20 seconds, which means to look as far as possible after opening a window). Currently research on myopia is extensive. Dopamine and its deficiency has been associated with the development and progression of myopia.[67] We are aware of the role of sunlight exposure and myopia. Also, Dopamine is directly proportional to the amount of playtime and sunlight exposure time, thereby linking itself to myopia. In addition, many pharmacological agents that have been clinically tried in the management of myopia are, in one way or the other, linked to the basic research of dopamine. We have previously shown and reported the detection of dopamine levels from the tear fluid of humans via ELISA.[8] In our unpublished data, we observed lower dopamine levels in the tears of the myopic patients as compared to normal controls. However, there is a need to validate the relationship between myopia, dopamine and various pharmacological and non-pharmacological options in myopic progression, which can provide more promising treatment options in the future. With the rise in myopia and myopia progression, one can expect an increase in the incidence of its complications like glaucoma, cataract, retinal degenerations, etc. Therefore, ophthalmologists must monitor myopes at regular intervals and watch out for these sight-threatening complications. To conclude, the management of myopia will always be a customized approach, depending on the risk factors and the features at the time of presentation. We hope future studies and newer treatment options provide an apt solution to prevent progression in this myopia pandemic.

Manganese‐Induced Highly Fluorescent Oligodopamine for Sensitive Detection of Dopamine Neurotransmitter by Catalytic Action of H2O2/MnO2 Nanosheets

Dopamine (DA) is a catecholamine, which plays an important role as neurotransmitter in the central nervous system. Optical sensing technology is commonly used for the rapid detection of DA through the formation of fluorescent polydopamine (PDA). However, it is difficult to quantify low levels of DA (≤10−8 m) because the resulting PDA has a low fluorescence (FL) efficiency. In this study, DA analyte is polymerized into highly fluorescent oligodopamine (F‐ODA) by the catalytic action of H2O2/MnO2 nanosheets, so‐called Mn2+@F‐ODA (i.e., manganese (2+) coordinated oligodopamine derivatives). Compared to the F‐ODA prepared by NaOH oxidation, Mn2+@F‐ODA exhibits a stronger FL intensity with a maximal peak at 465 nm. Mn2+@F‐ODA produces a distinct FL emission that allows for the detection of trace DA (10−8–10−12 m) with a detection limit of 10−13 m. The FL intensity of Mn2+@F‐ODA shows a suitable logarithmic linearity over four orders of the magnitude from 10−8–10−11 m. The developed chemical strategy suggests potential applications of Mn2+@F‐ODA for the sensitive detection of DA neurotransmitters.

Neurochemical Modulating Effect of Boswellia serrata Roxb. ex Colebr: A Preclinical Research


 
 
 
 Background: Boswellia serrata has been known for many decades and mentioned in the ancient Ayurvedic texts. Many previous studies have demonstrated its role in depression and anxiety in animal models.
 Objectives: The present study is carried out to evaluate the effect of Boswellia serrata on neurotransmitter levels of Swiss albino mice by spectrophotometer.
 Methods: Eighteen (n=18) Swiss albino male mice were procured for this study. All mice were divided into three groups of six mice in each. The first group of mice (control) received normal saline (10 mg/kg); the second group (standard) received imipramine (10 mg/kg), and the third group (test) received Boswellia serrata (100 mg/kg) orally for 21 days. On the 22nd day, all mice were sacrificed as per CPCSEA (Committee for the Purpose of Control and Supervision of Experiments on Animals) guidelines. The mice brains were dissected, and their brain tissue was collected and stored in a preservative. The mice brain tissue was centrifuged, and samples were used for the estimation of serotonin (5-HT), Acetylcholinesterase (AChE), dopamine, Gamma-Aminobutyric Acid (GABA), and glutamate levels by spectrophotometry.
 Results: The levels of neurotransmitters are expressed in Mean±SE. Analysis of results was done by 1-way ANOVA and Tukey Kramer tests. The statistical tests revealed that imipramine- treated mice have significantly increased the levels of AChE, GABA, and glutamate when compared to control (P<0.05). However, imipramine treated group showed statistically significant lower levels of 5-HT and dopamine levels when compared to the control (P<0.05). Similarly, the test drug Boswellia serrata-treated group had significantly higher levels of 5-HT, AChE, GABA, and glutamate when compared to the control group (P<0.05) and lower levels of dopamine when compared to the control (P<0.05).
 Conclusion: The present study establishes the role of Boswellia serrata in various psychiatric disorders like depression and anxiety in animal models by modulating multiple neurotransmitters in the brain.
 
 
 

Contributions of the Catechol-O-Methyltransferase Val158Met Polymorphism to Changes in Brain Iron Across Adulthood and Their Relationships to Working Memory

Ageing is associated with excessive free brain iron, which may induce oxidative stress and neuroinflammation, likely causing cognitive deficits. Lack of dopamine may be a factor behind the increase of iron with advancing age, as it has an important role in cellular iron homoeostasis. We investigated the effect of COMT Val 158 Met (rs4680), a polymorphism crucial for dopamine degradation and proxy for endogenous dopamine, on iron accumulation and working memory in a longitudinal lifespan sample (n = 208, age 20–79 at baseline, mean follow-up time = 2.75 years) using structural equation modelling. Approximation of iron content was assessed using quantitative susceptibility mapping in striatum and dorsolateral prefrontal cortex (DLPFC). Iron accumulated in both striatum and DLPFC during the follow-up period. Greater iron accumulation in DLPFC was associated with more deleterious change in working memory. Older (age 50–79) Val homozygotes (with presumably lower endogenous dopamine) accumulated more iron than older Met carriers in both striatum and DLPFC, no such differences were observed among younger adults (age 20–49). In conclusion, individual differences in genetic predisposition related to low dopamine levels increase iron accumulation, which in turn may trigger deleterious change in working memory. Future studies are needed to better understand how dopamine may modulate iron accumulation across the human lifespan.

Responsivity of the Striatal Dopamine System to Methylphenidate-A Within-Subject I-123-β-CIT-SPECT Study in Male Children and Adolescents With Attention-Deficit/Hyperactivity Disorder.

Background:Methylphenidate (MPH) is the first-line pharmacological treatment of attention-deficit/hyperactivity disorder (ADHD). MPH binds to the dopamine (DA) transporter (DAT), which has high density in the striatum. Assessments of the striatal dopamine transporter by single positron emission computed tomography (SPECT) in childhood and adolescent patients are rare but can provide insight on how the effects of MPH affect DAT availability. The aim of our within-subject study was to investigate the effect of MPH on DAT availability and how responsivity to MPH in DAT availability is linked to clinical symptoms and cognitive functioning.MethodsThirteen adolescent male patients (9–16 years) with a diagnosis of ADHD according to the DSM-IV and long-term stimulant medication (for at least 6 months) with MPH were assessed twice within 7 days using SPECT after application of I-123-β-CIT to examine DAT binding potential (DAT BP). SPECT measures took place in an on- and off-MPH status balanced for order across participants. A virtual reality continuous performance test was performed at each time point. Further clinical symptoms were assessed for baseline off-MPH.ResultsOn-MPH status was associated with a highly significant change (−29.9%) of striatal DAT BP as compared to off-MPH (t = −4.12, p = 0.002). A more pronounced change in striatal DAT BP was associated with higher off-MPH attentional and externalizing symptom ratings (Pearson r = 0.68, p = 0.01). Striatal DAT BP off-MPH, but not on-MPH, was associated with higher symptom ratings (Pearson r = 0.56, p = 0.04).ConclusionOur findings corroborate previous reports from mainly adult samples that MPH changes striatal DAT BP availability and suggest higher off-MPH DAT BP, likely reflecting low baseline DA levels, as a marker of symptom severity.

Neuroprotective effects of catechins in an experimental Parkinson’s disease model and SK-N-AS cells: evaluation of cell viability, anti-inflammatory and anti-apoptotic effects

ABSTRACT Objectives The aim of the study was to establish an in vitro Parkinson’s disease (PD) model and to investigate the cell viability, anti-inflammatory, anti-apoptotic and neuroprotective effects of catechin and EGCG in SK-N-AS and in vitro PD model cells. Method SK-N-AS human neuroblastoma cells were used. To develop an in vitro PD model, SK-N-AS cells were exposed to 6-hydroxydopamine. Model control was performed after ELISA analysis of dopamine and α-synuclein levels in the culture medium. Catechin and EGCG were administered to SK-N-AS and in vitro PD model cells. Cell viability was measured using MTT assay and trypan blue staining. Anti-inflammatory and anti-apoptotic activities of catechin and EGCG were investigated by indirect immunocytochemistry using anti-TNF-α, anti-IL-1β and anti-caspase-3. Results After 24 hours of 6-hydroxydopamine administration at 50 μM, higher αlfa-synuclein and lower dopamine levels were found in PD model than SK-N-AS cells. Cell viability was similar between SK-N-AS and in vitro PD model cells. Treatment with both bioactive components increased cell viability of in vitro PD model cells. Caspase-3 immunoreactivity was significantly reduced in SK-N-AS and PD model cells after EGCG administration, while it was decreased only in PD model cells after catechin administration. IL-1β staining intensity weakened after catechin administration in PD model cells, after EGCG administration in SK-N-AS cells. TNF-α staining intensity was similar in both cells. Conclusion Catechin and EGCG increased cell viability in PD model neuron cells. Both components showed anti-apoptotic and anti-inflammatory effects. Catechin may be more effective in preventing damage to neurons PD.

Dual-Pseudorabies Viral Tracing for Spinal Tyrosine Hydroxylase Interneurons Involved in Segmental Micturition Reflex Circuitry in Spinal Cord Injured Rats.

Traumatic spinal cord injury (SCI) often leads to urinary dysfunction. Although an involuntary micturition reflex can be established to elicit voiding with time, complications arise in the form of bladder hyper-reflexia and detrusor-sphincter dyssynergia that cause incontinence and inefficient expulsion of urine. To date, the neuronal mechanisms that underlie regulation of micturition after SCI are not well understood. We recently observed an increase of a population of tyrosine hydroxylase (TH)+ cells in the rat lumbosacral cord post-SCI, which contribute to the sustention of a low level of dopamine that modulates the recovered bladder reflex. To identify whether spinal TH+ cells are involved in the micturition reflex pathway post-SCI, two isoforms of the trans-synaptic retrograde tracer, pseudorabies virus encoding green fluorescent protein (GFP; PRV-152) or red fluorescent protein (RFP; PRV-614), were injected into the bladder detrusor or the external urethral sphincter (EUS), respectively, 3 weeks after a spinal cord transection at the 10th thoracic level (T10) in rats. Immunohistochemistry was performed to examine infected TH+ cells in the caudal cord at both 48 and 72 h post-injection. As a result, double-labeled TH+/GFP+ and TH+/RFP+ cells could be found in the superficial dorsal horn, parasympathetic nuclei, and dorsal gray commissure (lamina X) at both time points. More importantly, a shared population of TH+ interneurons (TH+/GFP+/RFP+) exists between bladder and EUS circuitry. These results suggest that spinal TH+ interneurons may coordinate activity of the bladder and EUS that occurs during micturition reflexes post-SCI.

Flexible sensor with electrophoretic polymerized graphene oxide/PEDOT:PSS composite for voltammetric determination of dopamine concentration

We demonstrate a novel, flexible sensor with graphene oxide/PEDOT:PSS (GO/PEDOT:PSS) composite for voltammetric determination of selective low levels of dopamine. The well-distributed GO and EDOT:PSS suspension in water were deposited simply and polymerized. Consequently, the EDOT:PSS provided a strong interaction between GO and PEDOT:PSS, and it also had well-tailored interfacial properties that allowed the highly selective and sensitive determination of DA. Since the interfacial net charge is well-constructed, the sensor satisfies both the requirements of selectivity and the highly sensitive detection of low amounts of DA. In the results, the sensor with the GO/PEDOT:PSS composite exhibited a low interfacial impedance of about 281.46 ± 30.95 Ω at 100 Hz and a high charge storage capacity (53.94 ± 1.08 µC/cm2) for the detection of dopamine. In addition, the interference from ascorbic acid was reduced effectively to a minimum by electrostatic charge repelling of the AA and the distinct difference for the oxidation peak of the UA. Due to the fact that the GO/PEDOT:PSS composite had a net negative charge and, enhanced interfacial properties, the sensor showed a dopamine detection limit of 0.008 μM and a sensitivity of 69.3 µA/µMcm2.

Fixing Pitx3 gene Mutation with CRISPR-Cas9 Intervention in Zygotic Aphakia-Prone Mice – A Research Protocol

Introduction: Despite the drawbacks of gene-editing, CRISPR-Cas9 remains a versatile tool for editing mutated genes. The mutated Pitx3 gene may cause aphakia in mice and Parkinsonism in humans. Pitx3 gene codes for the Pitx3 transcription factor involved in many tasks including the differentiation of dopaminergic neurons in the substantia nigra, tyrosine hydroxylase expression, dopamine transporter and lens development. We aim to edit mutated Pitx3 genes using CRISPR-Cas9 in embryonic-dopaminergic progenitor-neurons of mice and compare to wildtypes (WT) that do not undergo CRISPR-Cas9 intervention. Methods: We will use 5 female mice, 2 homozygous for mice aphakia/Pitx3 mutation (Ak) and 3 standard pseudo-pregnant females. 2-male homozygous (+/+ Ak) mice with Ak will mate with the aphakic females (+/+ Ak). Dopamine levels in both (aphakic/non-aphakic) mice will be determined. We will extract embryonic stem cells (ESC) from aphakic female’s uterus and treat with CRISPR-Cas9 and homology-directed repair (HDR). Both treated and untreated ESC will be divided between 3 pseudo-pregnant females. Post-parturition, intervention success will be assessed using presence of optical lens, dopamine levels and restriction sequence expression in treated/untreated progeny. Results: We expect to observe that untreated ESC zygotes (no CRISPR-Cas9 and HDR treatment) will not express normal Pitx3. This will result in low dopamine levels (inappropriate dopamine levels for their age group) and an aphakic mice progeny. Likewise, treated ESC zygotes will express normal Pitx3, hence have normal dopamine levels and non-aphakic phenotype. Discussion: Progeny of both groups (treated/non-treated) will be examined for aphakia, dopamine levels and restriction sequence. Dopamine levels of treated mice will be compared to dopamine levels of WT mice. Should none of the treated progeny develop lenses or have normal dopamine levels, these mice will be sacrificed to target the restriction sequence in the inserted gene — helping to evaluate why the inserted gene is unexpressed. Conclusion: This research examines CRISPR-Cas9 and HDR use on embryos with mutated genes that impair lens development and dopaminergic-neuron differentiation in humans and mice. It has potential of qualifying for clinical trials as the technique may be used to fix heritable disease-inducing genes that decrease longevity and quality of life in humans.