Metal coordination induced SERS nanoprobe for sensitive and selective detection of histamine in serum

Sensitivity and credibility detecting histamine (HA) as an important neurotransmitter in biofluids is of importance in analytical science and physiology. Surface-enhanced Raman spectroscopy (SERS) is able to realize the high sensitivity with single molecules level, but providing the high sensitivity for HA with a small cross section remains a challenge. Here we develop the metal complex-based SERS nanoprobe nitrilotriacetic acid-Ni²⁺ (NTA-Ni²⁺) combined with self-assemble Au NPs active substrates for sensitive detection of HA. The NTA-Ni²⁺ can capture the HA molecules close to Au NPs substrates and then amplify the Raman signals of HA owing to the formation of a complex of NTA-Ni²⁺-HA. The self-assemble Au film through the evaporation-driven method can provide the high-density hot spots substrate with high stability and reproducibility. The NTA-Ni²⁺ decorated Au NPs as nanoprobe responds to HA with 1 μM level of sensitivity. More importantly, the developed SERS nanoprobe composing of NTA-Ni²⁺ and self-assemble Au NPs can be utilized to detect and monitor the HA spiked into serum, indicating the potential prospect in analysis of HA in complex specimen.

Micro/nano-plastics cause neurobehavioral toxicity in discus fish (Symphysodon aequifasciatus): Insight from brain-gut-microbiota axis

Numerous studies have investigated neurobehavioral toxicity of microplastics, but no studies have illustrated mechanism via brain-gut axis. Here, juvenile discus fish (Symphysodon aequifasciatus) were exposed for 96 h to microfibers (900 µm, fiber, MFs) or nanoplastics (~88 nm, bead, NPs) with three concentrations (0, 20 and 200 µg/L). Accumulation in fish gut was independent of plastics type and concentration. MFs reduced growth performance while NPs weakened swimming and predatory performance of post-exposed discus. For brain cholinesterase activity, acetylcholinesterase was activated by NPs while NPs/MFs exposure inhibited butyrylcholinesterase. Concentrations of neurotransmitters (acetylcholine, dopamine and γ-aminobutyric acid) increased in brain but decreased in gut after NPs or MFs exposure. For gut microbiota, increased richness under MFs exposure was observed. At phylum level, Proteobacteria proportion was lower in NPs but higher in MFs. Abundance of Clostridia and Fusobacteriia (Bacillus), potentially secreting neurotransmitters, increased in NPs but decreased in MFs. Brain transcriptomics revealed seven upregulated and four downregulated genes concerning neural-activities. Pathways of neuroactive ligand-receptor interaction and serotonergic synapse were enriched in both MFs and NPs, but dopaminergic synapse pathway was enriched only in MFs. These results established a novel mechanism by which microplastics might cause behavioral toxicities via brain-gut-microbiota axis.

Rapid Isolation of Functional Synaptic Vesicles from Tissues Through Cryogrinding, Ultracentrifugation, and Size Exclusion Chromatography

Many biochemical and biophysical related questions require the isolation of functional synaptic vesicles. Isolated synaptic vesicles can be used for transporter kinetics studies, synaptic vesicle content analysis and immuno-labeling of specific synaptic vesicle proteins, etc. Here I describe a fast and reliable isolation procedure to allow researchers to isolate a large amount, as well as physiologically functional synaptic vesicles, by following the subsequent order of cryogrinding, gradient ultracentrifugation, and size exclusion liquid chromatography. This process enriches over 90% of the synaptic vesicle population, with low contamination of Golgi or endoplasmic reticulum vesicles.

Sleep, Sirtuin 1 and Alzheimer's disease: A review

Sleep plays a major role in brain health, and cognition. Disrupted sleep is a well-described symptom of Alzheimer's disease (AD). However, accumulating evidence suggests suboptimal sleep also increases AD risk. The deacetylase Sirtuin 1 (Sirt 1), encoded by the SIRT1 gene, impacts sleep via its relationship to wake-sleep neurotransmitters and somnogens. Evidence from animal and human studies supports a significant and complex relationship between sleep, Sirt 1/ SIRT1 and AD. Numerous hypotheses attempt to explain the critical impact of Sirt 1/ SIRT1 on wake- and sleep- promoting neurons, their related mechanisms and neurotransmitters. However, there is a paucity of studies assessing the interaction between sleep and Sirt 1/ SIRT1, as a principal component of sleep regulation, on AD pathology. In this review, we explore the potential association between Sirt 1/ SIRT1, sleep, and AD aetiology. Given sleep is a likely modifiable risk factor for AD, and recent studies suggest Sirt 1/ SIRT1 activation can be modulated by lifestyle or dietary approaches, further research in this area is required to explore its potential as a target for AD prevention and treatment.

Dopamine Gene Polymorphism, Biochemical and Oxidative Stress Parameters in Geriatric Population with and Without Depression: A Pilot Study

Dopamine transporter takes released dopamine back into presynaptic terminals and has been implicated in several aging disorders including depression. The present study was designed to demonstrate dopamine gene polymorphism, its circulatory levels, biochemical and oxidative stress parameters in geriatric population with and without depression. Thirty geriatric patients with depression and thirty age and sex matched normal controls were genotyped for Dopamine Active Transporter (DAT TaqA1 and DAT VNTR) gene polymorphisms using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method. The frequency of genotypes and alleles were compared in study groups. Biochemical markers, oxidative stress parameters, and dopamine levels were also measured using standard protocols and compared between patients and controls. The frequency distribution of DAT TaqA1 and DAT VNTR genotypes and alleles in patients were not statistically significant as compared to controls. At DAT TaqA1 gene polymorphism we found that the levels of dopamine were significantly high in genotypes A1A2 as compared to A2A2 (p ≤ 0.01). The present study demonstrated elevated levels of Catalase, Lipid Peroxide, and Glutathione Reductase, whereas decreased levels of Superoxide Dismutase, Dehydroepiandrosterone, Glutathione Peroxidase and Melatonin, in depressive patients as compared to controls. Our results clearly suggested that elevated mean levels of Catalase, Lipid Peroxides and Glutathione Reductase and decreased levels of Dehydroepiandrosterone, Superoxide Dismutase, Glutathione Peroxidase and Melatonin in depressed individuals may be a consequence of depression. Moreover, DAT TaqA1 allele A1 has a protective effect with high dopamine levels and DAT VNTR genotype 10R/10R has the highest protective effect followed by 9R/10R and 10R/11R.

Effect of Selenium on Brain Injury in Chickens with Subacute Arsenic Poisoning

The aim of this study was to investigate the effects of different doses of selenium (Se) on oxidative damage and neurotransmitter-related parameters in arsenic (As)-induced broiler brain tissue damage. Two hundred 1-day-old avian broilers were randomly divided into five groups and fed the following diets: control group (As 0.1 mg/kg + Se 0.2 mg/kg), As group (As 3 mg/kg + Se 0.2 mg/kg), low-Se group (As 3 mg/kg + Se 5 mg/kg), medium-Se group (As 3 mg/kg + Se 10 mg/kg), and high-Se group (As 3 mg/kg + Se 15 mg/kg). Glutathione (GSH), glutathione peroxidase (GSH-PX), nitric oxide (NO), nitric oxide synthase (NOS) activity, glutamate (Glu) concentration, glutamine synthetase (GS) activity, acetylcholinesterase (TchE) activity, and the apoptosis rate of brain cells were measured. The results showed that 3 mg/kg dietary As could induce oxidative damage and neurotransmitter disorder of brain tissue, increase the apoptosis rate of brain cells and cause damage to brain tissue, decrease activities of GSH and GSH-PX, decrease the contents of NO, decrease the activities of iNOS and tNOS, increase contents of Glu, and decrease activities of Gs and TchE. Compared with the As group, the Se addition of the low-Se and medium-Se groups protected against As-induced oxidative damage, neurotransmitter disorders, and the apoptosis rate of brain cells, with the addition of 10 mg/kg Se having the best effect. However, 15 mg/kg Se not only did not produce a protective effect against As damage but actually caused similar or severe damage.

C9orf72 hexanucleotide repeat expansion leads to altered neuronal and dendritic spine morphology and synaptic dysfunction

Frontotemporal lobar degeneration (FTLD) comprises a heterogenous group of progressive neurodegenerative syndromes. To date, no validated biomarkers or effective disease-modifying therapies exist for the different clinical or genetic subtypes of FTLD. The most common genetic cause underlying FTLD and amyotrophic lateral sclerosis (ALS) is a hexanucleotide repeat expansion in the C9orf72 gene (C9-HRE). FTLD is accompanied by changes in several neurotransmitter systems, including the glutamatergic, GABAergic, dopaminergic, and serotonergic systems and many clinical symptoms can be explained by disturbances in these systems. Here, we aimed to elucidate the effects of the C9-HRE on synaptic function, molecular composition of synapses, and dendritic spine morphology. We overexpressed the pathological C9-HRE in cultured E18 mouse primary hippocampal neurons and characterized the pathological, morphological, and functional changes by biochemical methods, confocal microscopy, and live cell calcium imaging. The C9-HRE-expressing neurons were confirmed to display the pathological RNA foci and DPR proteins. C9-HRE expression led to significant changes in dendritic spine morphologies, as indicated by decreased number of mushroom-type spines and increased number of stubby and thin spines, as well as diminished neuronal branching. These morphological changes were accompanied by concomitantly enhanced susceptibility of the neurons to glutamate-induced excitotoxicity as well as augmented and prolonged responses to excitatory stimuli by glutamate and depolarizing potassium chloride as compared to control neurons. Mechanistically, the hyperexcitation phenotype in the C9-HRE-expressing neurons was found to be underlain by increased activity of extrasynaptic GluN2B-containing N-methyl-d-aspartate (NMDA) receptors. Our results are in accordance with the idea suggesting that C9-HRE is associated with enhanced excitotoxicity and synaptic dysfunction. Thus, therapeutic interventions targeted to alleviate synaptic disturbances might offer efficient avenues for the treatment of patients with C9-HRE-associated FTLD.

Femtomolar detection of dopamine using surface plasmon resonance sensor based on chitosan/graphene quantum dots thin film

Due to the crucial role of dopamine (DA) in health and peripheral nervous systems, it is particularly important to develop an efficient and accurate sensor to monitor and determine DA concentrations for diagnostic purposes and diseases prevention. Up to now, using surface plasmon resonance (SPR) sensors in DA determination is very limited and its application still at the primary stage. In this work, a simple and ultra-sensitive SPR sensor was constructed for DA detection by preparation of chitosan- graphene quantum dots (CS-GQDs) thin film as the sensing layer. Other SPR measurements were conducted using different sensing layers; GQDs, CS for comparison. The proposed thin films were prepared by spin coating technique. The developed CS-GQDs thin film-based SPR sensor was successfully tested in DA concentration range from 0 fM to 1 pM. The designed SPR sensor showed outstanding performance in detecting DA sensitively (S = 0.011°/fM, R² = 0.8174) with low detection limit of 1.0 fM has been achieved for the first time. The increased angular shift of SPR dip, narrow full width half maximum of the SPR curves, excellent signal-to-noise ratio and figure of merit, and a binding affinity constant (K_A) of 2.962 PM^-1 demonstrated the potential of this sensor to detect DA with high accuracy. Overall, it was concluded that the proposed sensor would serve as a valuable tool in clinical diagnostic for the serious neurological disorders. This in turns has a significant socio-economic impact.

Characteristic expression of CGRP and osteogenic and vasculogenic markers in the proximal and distal regions of the rib during male mouse development

BACKGROUND

Neuropeptide calcitonin gene-related peptide (CGRP) is a neurotransmitter related to vasculogenesis and osteogenesis during bone formation and organ development. From the foetal period to the postnatal period, the thorax, which is necessary for lung respiration, forms. The thorax exhibits the same cartilage ossification as the bones of the extremities, but a specific system within the thorax exists as costal cartilage after birth. The relationship among CGRP, osteogenesis and vasculogenic markers in the two rib locations during thorax formation is not fully understood.

MATERIALS AND METHODS

In our study, male mice were used to provide ribs under different development conditions on various embryonic days (E12. 5, E14.5, and E17.5) and postnatal days (P1 and P5). The mRNA expression levels of CGRP, vascular endothelial growth factor (VEGF-A), type 1 collagen (Col1a-1), type 2 collagen (Col2a1), neuropeptide Y (NPY), osteocalcin (OCN) and osteopontin (OPN) were analysed by qRT-PCR. We also analysed the mRNA expression of CGRP, VEGF-A and OPN by in situ hybridization. Multivariate modelling with principal component analysis (PCA) was performed to estimate the interactions among the quantitative real-time RT-PCR data.

RESULTS

The mRNA expression levels of CGRP, VEGF-A, Col2a, Col1a-1, OCN, and NPY in the male mouse rib gradually increased during development. An antisense probe for CGRP mRNA was strongly detected in the central region of the mouse rib at E12.5 and the hypertrophic and ossification zones at E17.5 by in situ hybridization. VEGF-A was also located in the same region as CGRP at E12.5 and E17.5. OPN was strongly detected at the rib formation stage from E14.5 to E17.5. The expression of CGRP also differed between the proximal and distal regions of the rib at E17.5. As demonstrated by in situ hybridization, CGRP continuously participates in cartilage formation in the distal regions of the rib after birth. The PCA revealed that the mRNA expression of CGRP was related to that of Col1a-1 and VEGF-A during rib formation.

CONCLUSION

This study shows that CGRP is involved in vascular and bone formation during rib development and may also be involved in cartilage formation after birth. The findings suggest that CGRP may temporarily participate in bone formation and continuously participate in cartilage formation in the rib, which may also be related to the formation of the anterior thoracic wall after birth.

Semen Sojae Praeparatum alters depression-like behaviors in chronic unpredictable mild stress rats via intestinal microbiota

A large number of Chinese medical books present that Semen Sojae Praeparatum, a fermented food, possesses antidepressant effect, but the mechanism of this antidepressant effect remains largely unknown. This study aimed to explore the effect of Semen Sojae Praeparatum on rats with chronic unpredictable mild stress (CUMS)-induced depression. The results showed that Semen Sojae Praeparatum improved depression-like behaviors (negative preference of sugar water and increased swimming immobility time and time spent in the dark zone) and effectively reduced cell morphological changes in the dentate gyrus of the hippocampus in CUMS rats. In addition, Semen Sojae Praeparatum significantly promoted the contents of norepinephrine (NE), 5-hydroxytryptamine (5-HT), brain-derived neurotrophic factor (BDNF), and gamma-aminobutyric acid (GABA) in the hippocampus and the content of BDNF in the serum (p < 0.05). 16S rRNA sequencing analysis results showed that Semen Sojae Praeparatum increased the abundance of genus Ruminococcaceae_UCG-008 and decreased those of genera Lactobacillus and Bacteroides. Genus Ruminococcaceae_UCG-008 was positively correlated with GABA and BDNF levels in the hippocampus; genus Lactobacillus had a positive correlation with 5-HT; and genus Bacteroides had negative correlations with 5-HT, BDNF, and NE. In addition, Semen Sojae Praeparatum considerably decreased the concentration of short-chain fatty acids (SCFAs). These results indicated that Semen Sojae Praeparatum fermented by Rhizopus chinensis 12 and Bacillus sp. DU-106 alleviated the neurotransmitter levels and structural changes in the neuronal morphology of the hippocampus associated with the modulation of gut microbiota and SCFAs. Therefore, this study confirmed that Semen Sojae Praeparatum could alter depression and provide a theoretical basis for the investigation of the relationship between the microbiota-gut-brain axis and antidepressant.

Impaired mitochondrial functions and energy metabolism in MPTP-induced Parkinson's disease: comparison of mice strains and dose regimens

Heterogenous diseases such as Parkinson's disease (PD) needs an efficient animal model to enhance understanding of the underlying mechanisms and to develop therapeutics. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), a neurotoxin, has been widely used to replicate the pathophysiology of PD in rodents, however, the knowledge about its effects on energy metabolism is limited. Moreover, susceptibility to different dose regimens of MPTP also varies among mice strains. Thus, the present study compares the effect of acute and sub-acute MPTP administration on mitochondrial functions in C57BL/6 and BALB/c mice. In addition, activity of enzymes involved in energy metabolism was also studied along with behavioural alterations. The findings show that acute dose of MPTP in C57BL/6 mice had more profound effect on the activity of electron transport chain complexes. Further, the activity of MAO-B was increased following acute and sub-acute MPTP administration in C57BL/6 mice. However, no significant change was observed in BALB/c mice. Acute MPTP treatment resulted in decreased mitochondrial membrane potential along with increased swelling of mitochondria in C57BL/6 mice. In addition, perturbations were observed in hexokinase, the rate limiting enzyme of glycolysis and pyruvate dehydrogenase, the enzymes that connects glycolysis and TCA cycle. The activity of TCA cycle enzymes; citrate synthase, aconitase, isocitrate dehydrogenase and fumarase were also altered following MPTP intoxication. Furthermore, acute MPTP administration led to drastic reduction in dopamine levels in striatum of C57BL/6 as compared to BALB/c mice. Behavioral tests such as open field, narrow beam walk and footprint analysis revealed severe impairment in locomotor activity in C57BL/6 mice. These results clearly demonstrate that C57BL/6 strain is more vulnerable to MPTP-induced mitochondrial dysfunctions, perturbations in energy metabolism and motor defects as compared to BALB/c strain. Thus, the findings suggest that the dose and strain of mice need to be considered for pre-clinical studies using MPTP-induced model of Parkinson's disease.

Evaluation of the acute toxicity and neurodevelopmental inhibition of perfluorohexanoic acid (PFHxA) in zebrafish embryos

Perfluorohexanoic acid (PFHxA), a widely used emerging alternative for 8-carbon PFAAs, has been detected at a high level in the water environment. While its toxicity and environmental health risk are still largely unknown in aquatic life. The present study aimed to evaluated the possible developmental neurotoxicity induced by PFHxA exposure (0, 0.48, 2.4, and 12 mg/L for 120 h) in the zebrafish embryo. Here, both developmental endpoints, neurotransmitters concentrations, locomotor behavior were analyzed. No significant effects on mortality, malformation rate, and growth delay were detected in the low dose treatment groups except for in the high dose group (12 mg/L). A significant increase in swimming speed were noted in the 0.48 mg/L group. Other changes including neurotransmitters concentrations and green fluorescent protein (GFP) expression in Tg (HuC-GFP) zebrafish larvae were significantly increased in 12 mg/L group. Beyond that, genes related to neurodevelopment were significantly decreased in larvae. Moreover, downregulations of protein expression levels of α1-tubulin, elavl3, and gap43 were identified. These results demonstrate that the PFAAs alternative PFHxA have no significant neurodevelopmental effects on zebrafish larvae under acute low-dose exposure, while, it is important to note that PFHxA perform inhibiting effects on neurotransmitter and central nervous system under a relatively high dose. This in vivo study could provide reliable toxicity information for risk assessments of PFHxA on aquatic ecosystems. CAPSULE: PFHxA have no significant neurodevelopmental effects on zebrafish larvae under acute low-dose exposure, while exposed with relatively high-dose, could induced the alternations of neurotransmitter concentrations as well as the genes involved in the early developmental stages of zebrafish, leading to the impairment of the nervous system in zebrafish larvae.

Targeting neurotransmitter-mediated inflammatory mechanisms of psychiatric drugs to mitigate the double burden of multimorbidity and polypharmacy

The increased incidence of multimorbidities and polypharmacy is a major concern, particularly in the growing aging population. While polypharmacy can be beneficial, in many cases it can be more harmful than no treatment, especially in individuals suffering from psychiatric disorders, who have elevated risks of multimorbidity and polypharmacy. Age-related chronic inflammation and immunopathologies might contribute to these increased risks in this population, but the optimal clinical management of drug-drug interactions and the neuro-immune mechanisms that are involved warrants further investigation. Given that neurotransmitter systems, which psychiatric medications predominantly act on, can influence the development of inflammation and the regulation of immune function, it is important to better understand these interactions to develop more successful strategies to manage these comorbidities and complicated polypharmacy. I propose that expanding upon research in translationally relevant human in vitro models, in tandem with other preclinical models, is critical to defining the neurotransmitter-mediated mechanisms by which psychiatric drugs alter immune function. This will define more precisely the interactions of psychiatric drugs and other immunomodulatory drugs, used in combination, enabling identification of novel targets to be translated into more efficacious diagnostic, preventive, and therapeutic interventions. This interdisciplinary approach will aid in better precision polypharmacy for combating adverse events associated with multimorbidity and polypharmacy in the future.

Molecular fMRI of neurochemical signaling

Magnetic resonance imaging (MRI) is the most widely applied technique for brain-wide measurement of neural function in humans and animals. In conventional functional MRI (fMRI), brain signaling is detected indirectly, via localized activity-dependent changes in regional blood flow, oxygenation, and volume, to which MRI contrast can be readily sensitized. Although such hemodynamic fMRI methods are powerful tools for analysis of brain activity, they lack specificity for the many molecules and cell types that play functionally distinct roles in neural processing. A suite of techniques collectively known to as "molecular fMRI," addresses this limitation by permitting MRI-based detection of specific molecular processes in deep brain tissue. This review discusses how molecular fMRI is coming to be used in the study of neurochemical dynamics that mediate intercellular communication in the brain. Neurochemical molecular fMRI is a potentially powerful approach for mechanistic analysis of brain-wide function, but the techniques are still in early stages of development. Here we provide an overview of the major advances and results that have been achieved to date, as well as directions for further development.

Transcriptional analyses reveal different mechanism of toxicity for a chronic exposure to fluoxetine and venlafaxine on the brain of the marine fish Dicentrarchrus labrax

Selective serotonin reuptake inhibitor (SSRI) and serotonin norepinephrine reuptake inhibitor (SNRI) are prescribed for clinical depression and detected in aquatic ecosystems. The main aim of this study was to explore and evaluate transcriptional responses of neurotransmitter genes in the brain of a marine fish species, European seabass, and to analyze global brain transcriptomic changes by a RNA-seq technology (MACE, massive analysis of cDNA ends). The juveniles were exposed to two psychopharmaceuticals: (i) fluoxetine (FLX) at the concentration of 0.5 μg/L and 50 μg/L; (ii) venlafaxine (VENX) at the concentration of 0.01 μg/L and 1 μg/L. The exposures were performed for 21 days, followed by a 7-day recovery period to assess the reversibility of effects. Both psychopharmaceuticals affected differentially the neurotransmitter mRNA expression analyzed by RT-qPCR (serotonin receptors: 5-ht3a, 5-ht3b; dopamine receptors: d2, d3; neurotransmitter transporter: sert, vmat; degrading enzyme: mao). Transcriptomic analyses after 21 days of exposure revealed 689 and 632 significant different transcripts by FLX at 0.5 and 50 μg/L, respectively, and 432 and 1250 by VENX at 0.01 and 1 μg/L, respectively, and confirmed different mechanism of toxicity between both compounds. At environmental concentrations, more general pathways including energy metabolism were affected, while at the higher concentration effects on neurotransmitter pathways were observed (FLX: exocytosis and vesicle formation; VENX: small molecule catabolism regulating dopamine and tyrosine level). These results provided new insights into the chronic effects of psychopharmaceutical compounds on marine fish and suggest the need of a separate ecotoxicological risk analysis.

Neuroprotective efficacy of 4-Hydroxyisoleucine in experimentally induced intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe form of brain injury, which is a major cause of mortality in humans. Hydrocephalus and cerebral hematoma lead to severe neurological deficits. A single autologous blood (ALB) injection in rats' brains induces hemorrhage and other conditions that regularly interfere with the standard treatment of several cellular and molecular pathways. Several studies have found that IGF-1/GLP-1 decreases the production of inflammatory markers in peripheral tissues, while some have found that they also have pro-inflammatory functions. Since these receptors are down-regulated in hemorrhagic situations, we looked into the potential neuroprotective effect of 4-hydroxyisoleucine (4-HI); 50 mg/kg and 100 mg/kg, an active compound Trigonellafoenum-graecum, on post-hemorrhagic deficits in rats. Long-term oral administration of 4-HI for 35 days has improved behavioral and neurochemical deficits and severe pathological changes and improved cellular and molecular markers, apoptotic markers in the ALB-induced ICH experimental model.

Furthermore, the findings revealed that 4-HI also improved the levels of other neurotransmitters (Ach, DOPA, GABA, glutamate); inflammatory cytokines (TNF-alpha, IL-1β, IL-17), and oxidative stress markers (MDA, nitrite, LDH, AchE, SOD, CAT, GPx, GSH) in the brain when evaluated after Day 35. There is no proven treatment available for the prevention of post-brain hemorrhage and neurochemical malfunction; available therapy is only for symptomatic relief of the patient. Thus, 4-HI could be a potential clinical approach for treating post-brain haemorrhage and neurochemical changes caused by neurological damage. Furthermore, 4-HI may be linked to other standard therapeutic therapies utilized in ICH as a potential pharmacological intervention.

Effect of carbon nanomaterial dimension on the functional activity and degeneration of neurons

Despite growing concerns regarding the threat of airborne nanoparticle-mediated brain degeneration, the underlying pathological mechanisms remain unclear. Carbon nanomaterials, the main components of airborne nanoparticles, have multi-dimensional structures. Therefore, the dimensional effect of carbon-based nanomaterials on the regulation of neural function in brain disorders requires additional clarification. Herein, we report the interaction between zero-to three-dimensional carbon nanostructures and the amyloid-beta protein, which can either activate or interrupt neuronal functions, depending on the dimension of the carbon nanostructures. The carbon nanomaterials induced significant cellular activation by short-term exposure, while prolonged exposure eventually caused neuronal cell death. Such dimension-dependent activation or degeneration was more evident in the higher-dimension carbon nanomaterials, as confirmed by the increases in neurotransmitter secretion and synapse-related protein levels to more than five times at 72 h of monitoring and calcium signaling in the neurons. The inclusion of amyloid-beta proteins ameliorated the cytotoxic effects of carbon nanomaterials in higher-dimensional carbon nanomaterials by regulating 333 genes. We found that the ɑ-synuclein gene is the key factor in carbon-induced abnormal neuronal function. Therefore, through biological analyses and in vitro feasibility studies, this new insight may contribute toward understanding the pathological mechanism and finding a new target for therapy in human brain pathologies.

Bisphenol A impairs cognitive function and 5-HT metabolism in adult male mice by modulating the microbiota-gut-brain axis

Bisphenol A (BPA) has been found to promote hepatotoxicity, reproductive toxicity, and developmental toxicity. However, the neurotoxicity and mechanism of BPA on cognitive function are still unclear. To that end, eight-week-old adult male and female C57BL/6J mice were exposed to 0.05, 0.5, 5, and 50 mg/kg BPA by dietary supplementation for 22 weeks. BPA exposure impaired learning and memory in male mice, associated with increased neuroinflammation and damaged blood-brain barrier. BPA exposure reduced the tight junctions in the colon, resulting in dysfunction of the gut barrier. The levels of neurotransmitters in the serum, hippocampus, and colon of male mice, including tryptophan, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid, were all decreased by BPA, together with reduced expression of tryptophan and 5-HT metabolism-related genes. Cecal microbiota analysis revealed that the diversity and composition of the microbiota in male mice were markedly altered by BPA, leading to functional profile changes in the microbial community. These results suggest that the neurotoxicity of BPA in male mice may be partly regulated by the interactions of the microbiota-gut-brain axis. However, BPA has little effect on the cognitive function in female mice, which might be caused by the microbial differences and the role of estrogen receptors.

Placental Changes in the serotonin transporter (Slc6a4) knockout mouse suggest a role for serotonin in controlling nutrient acquisition

INTRODUCTION

The mouse placenta accumulates and possibly produces serotonin (5-hydroxytryptamine; 5-HT) in parietal trophoblast giant cells (pTGC) located at the interface between the placenta and maternal deciduum. However, the roles of 5-HT in placental function are unclear. This lack of information is unfortunate, given that selective serotonin-reuptake inhibitors are commonly used to combat depression in pregnant women. The high affinity 5-HT transporter SLC6A4 (also known as SERT) is the target of such drugs and likely controls much of 5-HT uptake into pTGC and other placental cells. We hypothesized that ablation of the Slc6a4 gene would result in morphological changes correlated with placental gene expression changes, especially for those involved in nutrient acquisition and metabolism, and thereby, provide insights into 5-HT placental function.

METHODS

Placentas were collected at embryonic age (E) 12.5 from Slc6a4 knockout (KO) and wild-type (WT) conceptuses. Histological analyses, RNAseq, qPCR, and integrative correlation analyses were performed.

RESULTS

Slc6a4 KO placentas had a considerable increased pTGC to spongiotrophoblast area ratio relative to WT placentas and significantly elevated expression of genes associated with intestinal functions, including nutrient sensing, uptake, and catabolism, and blood clotting. Integrative correlation analyses revealed upregulation of many of these genes was correlated with pTGC layer expansion. One other key gene was dopa decarboxylase (Ddc), which catalyzes conversion of L-5-hydroxytryptophan to 5-HT.

DISCUSSION

Our studies possibly suggest a new paradigm relating to how 5-HT operates in the placenta, namely as a factor regulating metabolic functions and blood coagulation. We further suggest that pTGC might be functional analogs of enterochromaffin 5-HT-positive cells of the intestinal mucosa, which regulate similar activities within the gut. Further work, including proteomics and metabolomic studies, are needed to buttress our hypothesis.

In search of sex-related mediators of affective illness

Sex differences in the rates of affective disorders have been recognized for decades. Studies of physiologic sex-related differences in animals and humans, however, have generally yielded little in terms of explaining these differences. Furthermore, the significance of these findings is difficult to interpret given the dynamic, integrative, and highly context-dependent nature of human physiology. In this article, we provide an overview of the current literature on sex differences as they relate to mood disorders, organizing existing findings into five levels at which sex differences conceivably influence physiology relevant to affective states. These levels include the following: brain structure, network connectivity, signal transduction, transcription/translation, and epigenesis. We then evaluate the importance and limitations of this body of work, as well as offer perspectives on the future of research into sex differences. In creating this overview, we attempt to bring perspective to a body of research that is complex, poorly synthesized, and far from complete, as well as provide a theoretical framework for thinking about the role that sex differences ultimately play in affective regulation. Despite the overall gaps regarding both the underlying pathogenesis of affective illness and the role of sex-related factors in the development of affective disorders, it is evident that sex should be considered as an important contributor to alterations in neural function giving rise to susceptibility to and expression of depression.

Long-term low-dose oxytetracycline potentially leads to neurobehavioural changes

Trace levels of oxytetracycline (OTC)-a veterinary antibiotic and feed additive-are widespread in the environment. Studies revealed that OTC potentially impairs thyroid function, which may affect neurobehaviour; however, the impact of exposure to environmental concentrations of OTC on adult neurobehaviour is unknown. In this study, the effects of OTC on zebrafish after 30-day exposure were investigated. The total swimming distance was significantly increased under vibration and light/dark stimulation, while time spent in the white area was prolonged during the black/white preference test, indicating that the zebrafish became bolder and more impulsive under low OTC exposure. Additionally, monoamine neurotransmitter (5-hydroxytryptamine, dopamine, norepinephrine) levels were decreased and gene expression of monoamine oxidase (mao) involved in neurotransmitter metabolism was upregulated at the transcription level after OTC exposure. Because triiodothyronine (T3) levels were enhanced following exposure to OTC, we speculated that T3 may mediate OTC damage to the nervous system. Our simulated molecular docking analysis showed that OTC combined with the sodium iodide cotransporter protein may result in excessive T3 synthesis. We further exposed zebrafish to T3, and they exhibited similar behaviour to the OTC exposure group. In conclusion, environmental OTC may activate monoamine oxidase and enhance the metabolism of monoaminergic neurotransmitters via T3, thereby inducing abnormal neurobehaviour.

Antidepressant-like effect of dehydrozingerone from Zingiber officinale by elevating monoamines in brain: in silico and in vivo studies

BACKGROUND

Dehydrozingerone (DHZ) is an active ingredient of Zingiber officinale and structural half analogue of curcumin. In the present study, DHZ was evaluated for monoamine oxidase (MAO) inhibitory activity in silico and antidepressant activity in vivo.

METHOD

The binding affinity of DHZ with MAO-A (PDB ID: 2Z5Y) was assessed using Schrodinger's Maestro followed by free energy calculation, pharmacokinetic property prediction using Qikprop and Molecular dynamics simulation using Desmond. In vivo antidepressant activity of DHZ was evaluated on C57 BL/6 male mice using Escilatopram as the standard antidepressant. Open field test (OFT), forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant effect of the drugs on days 1 and 7. Following the behavioural study, neurotransmitters (noradrenaline, dopamine and serotonin) were estimated using liquid chromatography-mass spectrometry.

RESULTS

DHZ demonstrated a greater binding affinity for the MAO-A enzyme compared to moclobemide in silico. Immobility in TST and FST were significantly (p < 0.05) reduced in vivo with 100mg/kg DHZ as compared to respective controls. DHZ treatment was more effective 1 h post treatment compared to vehicle control. A significant increase in levels of neurotransmitters was observed in mice brain homogenate in response to DHZ treatment, reassuring its antidepressant-like potential.

CONCLUSION

DHZ demonstrated MAO-A inhibition in silico, and the increased neurotransmitter levels in the brain in vivo were associated with an antidepressant-like effect.

New insights into neuropeptides regulation of immune system and hemopoiesis: effects on hematologic malignancies

Several neurotransmitters and neuropeptides were reported to join to or to cooperate with different cells of the immune system, bone marrow, and peripheral cells and numerous data support that neuroactive molecules might control immune system activity and hemopoiesis operating on lymphoid organs, and the primary hematopoietic unit, the hematopoietic niche. Furthermore, many compounds seem to be able to take part to the leukemogenesis and lymphomagenesis process, and in the onset of multiple myeloma. In this review, we will assess the possibility that neurotransmitters and neuropeptides may have a role in the onset of haematological neoplasms, may affect the response to treatment or may represent a useful starting point for a new therapeutic approach. More in vivo investigations are needed to evaluate neuropeptide's role in haematological malignancies and the possible utilization as an antitumor therapeutic target. Comprehending the effect of the pharmacological administration of neuropeptide modulators on hematologic malignancies opens up new possibilities in curing clonal hematologic diseases to achieve more satisfactory outcomes.

Molecular mechanisms of lidocaine

Lidocaine is an amide-class local anesthetic used clinically to inhibit pain sensations. Systemic administration of lidocaine has antinociceptive, antiarrhythmic, anti-inflammatory, and antithrombotic effects. Lidocaine exerts these effects under both acute and chronic pain conditions and acute respiratory distress syndrome through mechanisms that can be independent of its primary mechanism of action, sodium channel inhibition. Here we review the pathophysiological underpinnings of lidocaine's role as an anti-nociceptive, anti-inflammatory mediated by toll-like receptor (TLR) and nuclear factor kappa-β (NF-kβ) signalling pathways and downstream cytokine effectors high mobility group box 1 (HMGB1) and tumour necrosis factor-α (TNF-α).

Some Kinetic Features of Na,K-ATPase and Sensitivity to Noradrenaline

A comparative kinetic analysis of albino rat brain synaptic and kidney plasma membrane fraction Na,K-ATPase was performed to comprehend the different levels of sensitivity of these fractions to the neurotransmitter noradrenaline. Noradrenaline (NA) inhibits the rat brain synaptic membrane Na,K-ATPase, changes the stoichiometry of Na⁺ and K⁺ and shifts the enzyme system from an MgATP to an Mg²⁺ dependent cycle. While the kidney plasma membrane fraction Na,K-ATPase is not sensitive to noradrenaline. To investigate the mechanism underlying this difference, we studied enzyme velocity dependence on the concentration of Mg²⁺. The 1/V = f(Mg²⁺) function has shown different kinetic features for the synaptic and kidney plasma membrane Na,K-ATPase. With the addition of ethylene glycol tetraacetic acid (EGTA) to the reaction medium the geometric form of 1/V = f(Mg²⁺) function is affected differently. We thereafter measured the essential activator number for Na⁺ and K⁺ with, in excess Mg²⁺. The results of these experiments reveal that, contrary to the synaptic membrane Na,K-ATPase, the kidney plasma membrane fraction Na,K-ATPase does not possess an Mg²⁺ dependent cycle and noradrenaline exhibits different modulatory effects on the enzyme system.