Carbon powder-filled microelectrode: An easy-to-fabricate probe for cellular electrochemistry

Carbon fiber and carbon fiber disc microelectrodes are widely used for electrochemical detection of biochemicals released from cells. However, fabricating these types of microelectrodes is difficult and time-consuming. Here, we report an easy-to-fabricate, carbon powder-filled microelectrode consisting of a pulled glass capillary backfilled with carbon powder. Carbon tip size and responsiveness can be controlled by adjusting the settings of the puller. Carbon powder-filled microelectrodes with tip opening diameters of 7-24 μm detected sub-micromolar to sub-millimolar levels of dopamine and catecholamines released from PC-12 cells. This simple microelectrode should promote further work on cellular and tissue electrochemistry.

Development of neuronal circuits: From synaptogenesis to synapse plasticity

Optimal brain function critically hinges on the remarkably precise interconnections made among millions of neurons. These specialized interconnected neuronal junctions, termed synapses, are used for neuronal communication, whence the presynaptic neurons releases a specific neurotransmitter, which then binds to the appropriate protein receptor on the membrane of the postsynaptic neuron, activating and eliciting a response in this connected neuron. In this chapter, we discuss how synapses form and are modified as the brain matures. Genetic programs control most of the wiring in the brain, from allowing axons to choose where to target their synapses, to determining synapse identity. However, the final map of neuronal connectivity in the brain crucially relies on incoming sensory information during early childhood to strengthen and refine the preexisting synapses thus allowing both nature and nurture to shape the final structure and function of the nervous system (Fig. 5.1). Finally, we discuss how advances in the knowledge of basic mechanisms governing synapse formation and plasticity can shed light on the pathophysiology of neurodevelopmental disorders.

Residual effects of abomasal 5-hydroxytryptophan administration on serotonin metabolism in cattle

Studies of serotonin in animal husbandry has received growing interest. However, there is limited information about serotonin manipulation using 5-HTP administered postruminally and its residual effects in cattle. The objective of this study was to evaluate the effectiveness of 5-HTP infused into the abomasum for enhancing circulating serotonin in cattle. Four Holstein steers (487 ± 7.6 kg) fitted with ruminal cannulas were used in a 4 × 4 Latin Square design experiment. The treatments were intra-abomasal infusion of 5-HTP at 0, 0.25, 0.5, and 1 mg/kg BW. Blood was collected from the jugular vein of each steer at -60, -30, 0, 30, 60, 120, 240, and 480 min from 5-HTP infusion for basal and short term evaluation and, at 1, 2, 4, and 7 d after 5-HTP infusion for long term evaluation. Dry matter intake was not affected (P > 0.05) by intra-abomasal infusions. The half-life of 5-HTP was dose-independent (128 min). The serum 5-HTP, serotonin, and 5-hydroxyindoleacetic acid area under the curve increased (P < 0.05) linearly with an increased dose of 5-HTP. Serum 5-HTP reached peak concentration in approximately 30 min after dosing while serum and plasma serotonin peaked after 240 min postinfusion. Serotonin was greater than control for all 5-HTP doses 1 d and 2 d after infusion in serum and plasma, respectively. Intra-abomasal infusion of 5-HTP at doses up to 1 mg/ kg BW increases circulating serotonin for up 2 days.

Response of tyramine and glutamate related signals to nanoplastic exposure in Caenorhabditis elegans

Neurotransmission related signals are involved in the control of response to toxicants. We here focused on the tyramine and the glutamate related signals to determine their roles in regulating nanoplastic toxicity in Caenorhabditis elegans. In the range of μg/L, exposure to nanopolystyrene (100 nm) increased the expression of tdc-1 encoding a tyrosine decarboxylase required for synthesis of tyramine, and decreased the expression of eat-4 encoding a glutamate transporter. Both TDC-1 and EAT-4 could act in the neurons to regulate the nanopolystyrene toxicity. Meanwhile, neuronal RNAi knockdown of tdc-1 induced a susceptibility to nanopolystyrene toxicity, and neuronal RNAi knockdown of eat-4 induced a resistance to nanopolystyrene toxicity. In the neurons, TYRA-2 functioned as the corresponding receptor of tyramine and acted upstream of MPK-1 signaling to regulate the nanopolystyrene toxicity. Moreover, during the control of nanopolystyrene toxicity, GLR-4 and GLR-8 were identified as the corresponding glutamate receptors, and acted upstream of JNK-1 signaling and DBL-1 signaling, respectively. Our results demonstrated the crucial roles of tyramine and glutamate related signals in regulating the toxicity of nanoplastics in organisms.

Bimodal neural probe for highly co-localized chemical and electrical monitoring of neural activities in vivo

Investigation of the chemical and electrical signals of cells in vivo is critical for studying functional connectivity and brain diseases. Most previous studies have observed either the electrical signals or the chemical signals of cells because recording electrical signals and neurochemicals are done by fundamentally different methods. Herein, we present a bimodal MEMS neural probe that is monolithically integrated with an array of microelectrodes for recording electrical activity, microfluidic channels for sampling extracellular fluid, and a microfluidic interface chip for multiple drug delivery and sample isolation from the localized region at the cellular level. In this work, we successfully demonstrated the functionality of our probe by monitoring and modulating bimodal (electrical and chemical) neural activities through the delivery of chemicals in a co-localized brain region in vivo. We expect our bimodal probe to provide opportunities for a variety of in-depth studies of brain functions as well as for the investigation of neural circuits related to brain diseases.

Improved LC-MS/MS method for the determination of 42 neurologically and metabolically important molecules in urine

Simultaneous determination of kynurenines, neurotransmitters, pterins and steroids linked to various neurological and metabolic diseases have important diagnostic significance for related pathology and drug monitoring. An improved, sensitive and selective ultra-high performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometric (UHPLC-MS/MS) method, based on our earlier publication, has been proposed for the quantitative measurement of 42 metabolites in human urine. The assay covers a larger number of analytes, uses an advanced, Waters Atlantis T3 chromatographic column and similarly meets the guideline of European Medicines Agency (EMA) on bioanalytical method validation. Analytical performance met all the EMA requirements and the assay covered the relevant clinical concentrations. Linear correlation coefficients were all > 0.998. Intra-day and inter-day accuracy and precision were 87-118%, 81-120% and 2-20%, respectively including the lower limit of quantification (LLOQ). The assay is expected to facilitate the diagnosis and allows drug level monitoring from urine.

Rapid quantification of extracellular neurotransmitters in mouse brain by PESI/MS/MS and longitudinal data analysis using the R and Stan-based Bayesian state-space model

We developed a methodology for rapid quantification of extracellular neurotransmitters in mouse brain by PESI/MS/MS and longitudinal data analysis using the R and Stan-based Bayesian state-space model. We performed a rapid analysis for quantifying extracellular l-glutamic acid (L-Glu) and gamma-aminobutyric acid (GABA) in the mouse striatum by combined use of probe electrospray ionization/tandem mass spectrometry (PESI/MS/MS) and in vivo brain microdialysis. We optimized the PESI/MS/MS parameters with the authentic L-Glu, GABA, L-Glu-¹³C₅,¹⁵N₁, and GABA-D₆ standards. We constructed calibration curves of L-Glu and GABA with the stable isotope internal standard correction method (L-Glu-¹³C₅,¹⁵N₁, and GABA-D₆), demonstrating sufficient linearity (R > 0.999). Additionally, the quantitative method for L-Glu and GABA was validated with low-, middle-, and high-quality control samples. The intra- and inter-day accuracy and precision were 0.4%-7.5% and 1.7%-5.4% for L-Glu, respectively, and 0.1%-4.8% and 2.1%-5.7% for GABA, respectively, demonstrating high reproducibility of the method. To evaluate the feasibility of this method, microdialyses were performed on free-moving mice that were stimulated by high-K⁺-induced depolarization under different sampling conditions: 1) every 5 min for 150 min (n = 2) and 2) every 1 min for 30 min (n = 3). We applied the R and Stan-based Bayesian state-space model to each mouse's time-series data considering autocorrelation, and the model successfully detected abnormal changes in the L-Glu and GABA levels in each mouse. Thus, the L-Glu and GABA levels in all microdialysates approximately increased up to two- and seven-fold levels through high-K⁺-induced depolarization. Additionally, a 1-min temporal resolution was achieved using this method, thereby successfully monitoring microenvironmental changes in the extracellular L-Glu and GABA of the mouse striatum. In conclusion, this methodology using PESI/MS/MS and Bayesian state-space model allowed easy monitoring of neurotransmitters at high temporal resolutions and appropriate data interpretation considering autocorrelation of time-series data, which will reveal hidden pathological mechanisms of brain diseases, such as Parkinson's disease and Huntington's disease in the future.

Caesarean section and offspring's emotional development: Sex differences and the role of key neurotransmitters

Increasing caesarean section (CS) rates are of global concern not only for health care providers but also from a more general public health point of view. Growing concern on the association between CS and offspring's neurodevelopmental outcomes have been raised in recent years, but the effect of CS on offspring's emotional development is rarely reported. By using mice models, we have set up two groups, ie. offspring born via CS and in-fostered by dams with vaginal delivery (VD), and offspring born via VD and in-fostered by their non-biological mothers. Depression-like behavioral was evaluated by sucrose preference test and forced swimming test, and anxiety-like behavioral was evaluated by open-field test and elevated plus maze test, respectively during offspring's adolescence and adulthood. Offspring's prefrontal cortex was collected for HE staining and assessment for DA, HVA, 5-HT, 5-HIAA. It was found that offspring born of CS have anxiety-like and depression-like behaviors in adolescence and adulthood. Male offspring was sensitive to be depressive and female offspring tended to be anxious. Although no significant sex difference was observed, there existed edema and nuclear retraction of neurons in the prefrontal cortex in offspring via CS during adolescence and adulthood. Compared with offspring born via VD, offspring through CS had shown higher DA and HVA levels while lower 5-HT and 5-HIAA levels in adolescence and adulthood, and this difference was observed in female offspring. The findings highlight the sex-specific effect of CS on offspring's emotional development. Variations in key neurotransmitters in the prefrontal cortex may partly explain the association between CS and offspring's emotional symptoms.

A genetic interaction of NRXN2 with GABRE, SYT1 and CASK in migraine patients: a case-control study

BACKGROUND

Migraine is a multifactorial disorder that is more frequent (two to four times) in women than in men. In recent years, our research group has focused on the role of neurotransmitter release and its regulation. Neurexin (NRXN2) is one of the components of the synaptic vesicle machinery, responsible for connecting intracellular fusion proteins and synaptic vesicles. Our aim was to continue exploring the role and interaction of proteins involved in the control and promotion of neurotransmission in migraine susceptibility.

METHODS

A case-control study was performed comprising 183 migraineurs (148 females and 35 males) and 265 migraine-free controls (202 females and 63 males). Tagging single nucleotide polymorphisms of NRXN2 were genotyped to assess the association between NRXN2 and migraine susceptibility. The χ² test was used to compare allele frequencies in cases and controls and odds ratios were estimated with 95% confidence intervals. Haplotype frequencies were compared between groups. Gene-gene interactions were analysed using the Multifactor Dimensionality Reduction v2.0.

RESULTS

We found a statistically significant interaction model (p = 0.009) in the female group between the genotypes CG of rs477138 (NRXN2) and CT of rs1158605 (GABRE). This interaction was validated by logistic regression, showing a significant risk effect [OR = 4.78 (95%CI: 1.76-12.97)] after a Bonferroni correction. Our data also supports a statistically significant interaction model (p = 0.011) in the female group between the GG of rs477138 in NRXN2 and, the rs2244325's GG genotype and rs2998250's CC genotype of CASK. This interaction was also validated by logistic regression, with a protective effect [OR = 0.08 (95%CI: 0.01-0.75)]. A weak interaction model was found between NRXN2-SYT1. We have not found any statistically significant allelic or haplotypic associations between NRXN2 and migraine susceptibility.

CONCLUSIONS

This study unravels, for the first time, the gene-gene interactions between NRXN2, GABRE - a GABA_A-receptor - and CASK, importantly it shows the synergetic effect between those genes and its relation with migraine susceptibility. These gene interactions, which may be a part of a larger network, can potentially help us in better understanding migraine aetiology and in development of new therapeutic approaches.

Interactive regulation of laryngeal cancer and neuroscience

Nerve fibres are distributed throughout the body along with blood and lymphatic vessels. The intrinsic morphological characteristics of nerves and the general characteristics of secretions in the tumour microenvironment provide a solid theoretical basis for exploring how neuronal tissue can influence the progression of laryngeal cancer (LC). The central nervous system (CNS) and the peripheral nervous system (PNS) jointly control many aspects of cancer and have attracted widespread attention in the study of the progression, invasion and metastasis of tumour tissue banks. Stress activates the neuroendocrine response of the human hypothalamus-pituitary-adrenal (HPA) axis. LC cells induce nerve growth in the microenvironment by releasing neurotrophic factors (NTFs), and they can also stimulate neurite formation by secreting axons and axon guides. Conversely, nerve endings secrete factors that attract LC cells; this is known as perineural invasion (PNI) and promotes the progression of the associated cancer. In this paper, we summarize the systematic understanding of the role of neuroregulation in the LC tumour microenvironment (TME) and ways in which the TME accelerates nerve growth, which is closely related to the occurrence of LC.

Effects on the survival rates, hematological parameters, and neurotransmitters in olive flounders, Paralichthys olivaceus, reared in bio-floc and seawater by Streptococcus iniae challenge

Bacterial infections cause huge losses to aquaculture globally, and increased antibiotic resistance means that alternative methods of reducing mortality from bacterial diseases are required. We compared the resistance of Juvenile olive flounders, Paralichthys olivaceus, to Streptococcus iniae between those reared in biofloc and seawater conditions for ten months. Experimental fish were challenged with S. iniae at concentrations of 0, 3.36 × 10⁶, 3.36 × 10⁷, 3.36 × 10⁸, and 3.36 × 10⁹ colony forming units (CFU)/g fish for 96 h to evaluate the difference in S. iniae susceptibility of flounders reared in biofloc and seawater. The 96 h lethal concentration 50% (LC₅₀) of fish injected with S. iniae was 2.41 × 10⁹ CFU/g fish in biofloc and 1.51 × 10⁸ CFU/g fish in seawater. Hematological parameters such as hemoglobin and hematocrit significantly decreased when fish were challenged by S. iniae. Plasma components such as calcium, glucose, cholesterol, total protein, GOT, GPT, and ALP were significantly altered by S. iniae infection and acetylcholinesterase activity was significantly inhibited. These results indicate that S. iniae infection affects the survival rates, hematological parameters, and neurotransmitter levels of flounders reared in biofloc and seawater, and that S. iniae susceptibility was higher in flounders reared in seawater than those reared in biofloc.

Electrophysiology of ionotropic GABA receptors

GABA_A receptors are ligand-gated chloride channels and ionotropic receptors of GABA, the main inhibitory neurotransmitter in vertebrates. In this review, we discuss the major and diverse roles GABA_A receptors play in the regulation of neuronal communication and the functioning of the brain. GABA_A receptors have complex electrophysiological properties that enable them to mediate different types of currents such as phasic and tonic inhibitory currents. Their activity is finely regulated by membrane voltage, phosphorylation and several ions. GABA_A receptors are pentameric and are assembled from a diverse set of subunits. They are subdivided into numerous subtypes, which differ widely in expression patterns, distribution and electrical activity. Substantial variations in macroscopic neural behavior can emerge from minor differences in structure and molecular activity between subtypes. Therefore, the diversity of GABA_A receptors widens the neuronal repertoire of responses to external signals and contributes to shaping the electrical activity of neurons and other cell types.

Dopa-responsive dystonia, DRD-plus and DRD look-alike: a pragmatic review

Dopa-responsive dystonia (DRD) and DRD plus are diseases of the dopamine pathway with sizeable genetic diversity and myriad presentations. DRD has onset in childhood or adolescence with focal dystonia, commonly affecting lower limb, diurnal fluctuations with evening worsening of symptoms and a demonstrable sleep benefit. DRD "plus" has "atypical features" which include infantile onset, psychomotor delay, cognitive abnormalities, oculogyric crisis, seizures, irritability, spasticity, hypotonia, ptosis, hyperthermia and cerebellar dysfunction. Neurodegeneration, however, is not a feature of either DRD or DRD-plus disorders. Tetrahydrobiopterin (BH4), a key cofactor, deficiency leads to inadequate dopamine and serotonin synthesis. Norepinephrine deficiency may coexist, depending on the enzyme defect. Hyperphenylalaninemia (HPA) is a clue for BH4 paucity. However, HPA is conspicuously absent in autosomal-dominant guanosine triphosphate cyclohydrolase 1 deficiency and sepiapterin reductase deficiency. DRD look-alike is a group of neurodegenerative disorders involving the nigrostriatal dopaminergic system, which could present with dystonia responsive to dopaminergic drugs or neurodegenerative or non-neurodegenerative disorders without involving the nigrostriatal dopaminergic system yet responsive to levodopa. Although levodopa is the mainstay of therapy, response to this drug can be unsatisfactory in DRD plus and DRD look-alike and other drugs are tried. Simultaneous management of HPA leads to remarkable improvement in both motor and cognitive functions. The aim of this review is to help neurology practitioners in treating patients with DRD, DRD-plus and DRD look-alike as many of them have excellent outcome with appropriate therapy.

Plasma gamma-aminobutyric acid (GABA) levels and posttraumatic stress disorder symptoms in trauma-exposed women: a preliminary report

RATIONALE

Aberrations in the stress response are associated with posttraumatic stress disorder (PTSD) symptom development, maintenance, and severity. Gamma-aminobutyric acid (GABA), the brain's primary inhibitory neurotransmitter, may play a key role in stress recovery.

OBJECTIVES

In this preliminary study, we examined whether plasma GABA levels differed between women with PTSD and trauma-exposed healthy controls.

METHODS

Thirty participants provided plasma samples during two phases of the menstrual cycle: the early follicular phase and the mid-luteal phase. During each phase, blood was drawn after 45 min of rest, and after mild and moderately stressful psychophysiological tasks. Plasma GABA levels were measured using HPLC-mass spectrometry (LC-MS/MS).

RESULTS

In analyses using PTSD diagnosis as a categorical group variable, women with and without a diagnosis of PTSD did not differ in plasma GABA levels (ps > .18). However, in analyses examining PTSD symptom severity as a continuous variable, there was a trend-level positive association between more severe PTSD symptoms and higher plasma GABA levels across the four blood draws (p = .06). In analyses examining DSM-IV PTSD symptom clusters separately, dysphoria symptoms were positively and significantly associated with plasma GABA levels (p = .03). Similarly, there was a trend-level positive association between avoidance cluster symptoms and plasma GABA levels (p = .06). Plasma GABA levels were not modulated by experimentally induced stress or menstrual cycle phase.

CONCLUSIONS

Dysregulation in GABA may be a neurobiological marker and/or potential treatment target for women with PTSD symptom profiles characterized by prominent dysphoria and avoidance cluster symptoms.

Toxoplasma gondii: A possible etiologic agent for Alzheimer's disease

Toxoplasma gondii (T. gondii) is one of the most pervasive neurotropic pathogens causing different lesions in a wide variety of mammals as intermediate hosts, including humans. It is estimated that one-third of the world population is infected with T. gondii; however, for a long time, there has been much interest in the examination of the possible role of this parasite in the development of mental disorders, such as Alzheimer's disease (AD). T. gondii may play a role in the progression of AD using mechanisms, such as the induction of the host's immune responses, inflammation of the central nervous system (CNS), alteration in the levels of neurotransmitters, and activation of indoleamine-2,3-dyoxigenase. This paper presents an appraisal of the literature, reports, and studies that seek to the possible role of T. gondii in the development of AD. For achieving the purpose of the current study, a search of six English databases (PubMed, ScienceDirect, Web of Science, Scopus, ProQuest, and Google Scholar) was performed. The results support the involvement of T. gondii in the induction and development of AD. Indeed, T. gondii can be considered a risk factor for the development of AD and requires the special attention of specialists and patients. Furthermore, the results of this study may contribute to prevent or delay the progress of AD worldwide. Therefore, it is required to carry out further studies in order to better perceive the parasitic mechanisms in the progression of AD.

Association of blood lead level with neurobehavior and neurotransmitter expressions in Indian children

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BLL had a significant direct correlation with abnormal neurobehavior.

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Serum serotonin levels were significantly lower in children with high blood lead levels (BLL).

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Serum serotonin and dopamine receptor expression were upregulated in children with high BLL.

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Serum serotonin levels had significant negative association with adverse neurobehavior.

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Dopamine receptor expression had significant positive association with adverse neurobehavior.

Present study aimed to assess the alterations in neurotransmitter expression and its association with Blood Lead Level (BLL) and neurobehavioral pattern in children. 72 school going children were recruited. Blood lead levels were determined by Atomic Absorption Spectrophotometer. Neurobehavioral state was assessed by means of population specific scale i.e. CPMS (Childhood Psychopathological measurement Schedule). Serum serotonin and dopamine were estimated by ELISA, receptor and transporter gene expressions were assessed by quantitative real time PCR. Significant positive correlation was observed between Total CPMS score (i.e. adverse neurobehaviour) and BLL. Further, serum serotonin levels and dopamine receptor expression showed a negative and positive association with BLL, respectively. In similarity, serum serotonin levels showed a negative correlation and dopamine receptor expression had a significant positive correlation with total CPMS score. Environmental exposure to Lead (Pb) may result in significant alterations in the neurotransmitter levels which may be associated with neurobehavioral changes in the children exposed to Pb.

The dorsoanterior brain of adult amphioxus shares similarities in expression profile and neuronal composition with the vertebrate telencephalon

BACKGROUND

The evolutionary origin of the telencephalon, the most anterior part of the vertebrate brain, remains obscure. Since no obvious counterpart to the telencephalon has yet been identified in invertebrate chordates, it is difficult to trace telencephalic origins. One way to identify homologous brain parts between distantly related animal groups is to focus on the combinatorial expression of conserved regionalisation genes that specify brain regions.

RESULTS

Here, we report the combined expression of conserved transcription factors known to specify the telencephalon in the vertebrates in the chordate amphioxus. Focusing on adult specimens, we detect specific co-expression of these factors in the dorsal part of the anterior brain vesicle, which we refer to as Pars anterodorsalis (PAD). As in vertebrates, expression of the transcription factors FoxG1, Emx and Lhx2/9 overlaps that of Pax4/6 dorsally and of Nkx2.1 ventrally, where we also detect expression of the Hedgehog ligand. This specific pattern of co-expression is not observed prior to metamorphosis. Similar to the vertebrate telencephalon, the amphioxus PAD is characterised by the presence of GABAergic neurons and dorsal accumulations of glutamatergic as well as dopaminergic neurons. We also observe sustained proliferation of neuronal progenitors at the ventricular zone of the amphioxus brain vesicle, as observed in the vertebrate brain.

CONCLUSIONS

Our findings suggest that the PAD in the adult amphioxus brain vesicle and the vertebrate telencephalon evolved from the same brain precursor region in ancestral chordates, which would imply homology of these structures. Our comparative data also indicate that this ancestral brain already contained GABA-, glutamatergic and dopaminergic neurons, as is characteristic for the olfactory bulb of the vertebrate telencephalon. We further speculate that the telencephalon might have evolved in vertebrates via a heterochronic shift in developmental timing.

Neuro-immune communication in C. elegans defense against pathogen infection

The innate immune system is a complex collection of physical barriers and physiological defense responses to internal and external environmental assaults. Recent studies in the model organism Caenorhabditis elegans have highlighted how the nervous system interacts with the innate immune system to generate coordinated protective responses. Indeed, studies on neuro-immune interaction pathways have provided mechanistic insights into the roles of neuro-immune communication in modulating both immune and behavioral responses to pathogen attacks. The nervous system releases a variety of neurotransmitters, peptides, and hormones that regulate the innate immune response, while the innate immune system also relays information to the nervous system to affect learning and behavioral responses. Although these interactions still need further investigation, the knowledge that we have gained thus far has improved our understanding of how separate biological systems can act collectively for the survival and well-being of an organism. Here, we review recent studies on neuro-immune communication related to the survival and defense of C. elegans against pathogens.

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Neuro-immune communication is essential for generating coordinated defense against pathogen infection to improve host survival.

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Neuro-immune communication modulates both immune and behavioral responses to pathogen attacks.

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C.elegans is an excellent model system for studying neuro-immune communication.

Forty Four Years With Baruch Kanner and The Chloride Ion

Baruch Kanner and this author have had parallel careers investigating neurotransmitter transporters. At multiple times during their careers, they have found themselves collaborating or competing, but always learning from each other. This commentary elaborates on the interactions between the Kanner and Rudnick laboratories, with a focus on transporters in the Neurotransmitter: Sodium Symporter (NSS) family of amino acid and amine transporters. A key focus of these interactions is the mechanism by which chloride ions activate and drive transport.

Alpha-pyrrolidinopentiophenone and mephedrone self-administration produce differential neurochemical changes following short- or long-access conditions in rats

Stimulant-induced neurochemical changes may occur at different times for different brain regions or neurotransmitter systems. This study sought to examine the behavioral and neurochemical effects of extended access to α-pyrrolidinopentiophenone (α-PVP) and 4-methylmethcathinone (4MMC). Male and female Sprague-Dawley rats were trained to self-administer α-PVP (0.1 mg/kg/infusion) or 4MMC (0.5 mg/kg/infusion) through autoshaping, and then self-administered for 21 days during 1 h (short access; ShA) or 6 h (long access; LgA) sessions. Separate rats were assigned to a naïve control group. Amygdala, hippocampus, hypothalamus, prefrontal cortex (PFC), striatum, and thalamus were extracted, and tissue was analyzed with electrochemical detection and liquid chromatography mass spectrometry. Rats acquired self-administration of α-PVP and 4MMC, and LgA rats showed more escalation of self-administration than ShA rats. Synthetic cathinone administration produced several effects on neurotransmitters. LgA self-administration of α-PVP increased 5-HIAA levels in all brain regions, compared to control. In contrast, both LgA and ShA 4MMC self-administration decreased 5-HT and 5-HIAA levels in most brain regions. LgA exposure to both synthetic cathinones increased DOPAC levels in hypothalamus and striatum, and increased HVA levels in striatum compared to control. LgA self-administration of either synthetic cathinone produced region-specific increases in NE levels, whereas ShA self-administration lowered NE levels in select locations compared to control. These alterations in neurotransmitter levels indicate that synthetic cathinone use may produce differential neurochemical changes during the transition from use to abuse, and that 21 days of self-administration only models the beginning stages of dysregulated drug intake.

Melanocortin receptor-4 mediates the anorectic effect induced by the nucleus tractus solitarius injection of glucagon-like Peptide-2 in fasted rats

Glucagon-like peptide-2 (GLP-2) is secreted from enteroendocrine L-type cells of the gut and also released from preproglucagonergic (PPG) neurons in the nucleus tractus solitarius (NTS) and adjacent medial reticular nucleus of the brain stem. The neurons in the NTS express GLP-2, and the neurons send extensive projections to the hypothalamus. Recent studies show that the intracerebroventricular administration of GLP-2 significantly suppresses food intake in animals and some evidence suggest that the melanocortin receptor-4 (MC4-R) signaling in the hypothalamus is required for intracerebroventricular GLP-2-mediated inhibition of feeding. There is proopiomelanocortin (POMC) positive neurons expressing MC4-R in the NTS. Suppression of MC4-R expressing neurons in the brain stem inhibits gastric emptying. In this study, we tested the effects of NTS GLP-2R activation and blockade on feeding behavior and evaluated the endogenous melanocortin system's role in the NTS in mediating effects of GLP-2 on feeding behavior in fed and fasted rats. Our results demonstrated that microinjection of GLP-2 into the NTS suppressed food intake in fasted-refeeding rats but did not affect food intake in free-feeding rats, and this inhibition was blocked by pretreatment of either Exendin _(9-39) or SHU 9119, suggesting the GLP-2 system in the NTS exerts an inhibitory action on food intake. MC4-R mediates this action in the NTS.

Neandertal introgression and accumulation of hypomorphic mutations in the neuropeptide S (NPS) system promote attenuated functionality

The neuropeptide S (NPS) system plays an important role in fear and fear memory processing but has also been associated with allergic and inflammatory diseases. Genes for NPS and its receptor NPSR1 are found in all tetrapods. Compared to non-human primates, several non-synonymous single-nucleotide polymorphisms (SNPs) occur in both human genes that collectively result in functional attenuation, suggesting adaptive mechanisms in a human context. To investigate historic and geographic origins of these hypomorphic mutations and explore genetic signs of selection, we analyzed ancient genomes and worldwide genotype frequencies of four prototypic SNPs in the NPS system. Neandertal and Denisovan genomes contain exclusively ancestral alleles for NPSR1 while all derived alleles occur in ancient genomes of anatomically modern humans, indicating that they arose in modern Homo sapiens. Worldwide genotype frequencies for three hypomorphic NPSR1 SNPs show significant regional homogeneity but follow a gradient towards increasing derived allele frequencies that supports an out-of-Africa scenario. Increased density of high-frequency polymorphisms around the three NPSR1 loci suggests weak or possibly balancing selection. A hypomorphic mutation in the NPS precursor, however, was detected at high frequency in Eurasian Neandertal genomes and shows genetic signatures indicating that it was introgressed into the human gene pool, particularly in Southern Europe, by interbreeding with Neandertals. We discuss potential evolutionary scenarios including behavior and immune-based natural selection.

Quantum energy levels of glutamate modulate neural biophotonic signals

Glutamate is the most abundant excitatory neurotransmitter in the brain, and it plays an essential and important role in neural functions. Current studies have shown that glutamate can induce neural biophotonic activity and transmission, which may involve the mechanism of photon quantum brain; however, it is unclear whether such a mechanism follows the principle of quantum mechanics. Here we show that the action of glutamate on its receptors leads to a decrease in its quantum energy levels, and glutamate then partially or completely loses its function to further induce the biophotonic activity in mouse brain slices. The reduced quantum energy levels of glutamate can be restored by direct-current electrical discharges and the use of energy transfer of chloroplast photosynthesis; hence, the quantum energy recovered glutamate can again induce significant biophotonic activity. Furthermore, the changes in quantum energy levels of glutamate are related to the exchange and transfer of electron energy on its active hydrogen atom. These findings suggest that the glutamate-induced neural biophotonic signals may be involved in the transfer of the quantum energy levels of glutamate, which implies a quantum mechanism of neurotransmitter action.

MDMA and the Brain: A Short Review on the Role of Neurotransmitters in Neurotoxicity

N-Methyl-3, 4-methylenedioxyamphetamine (MDMA), or ecstasy is a recreational drug of abuse. It is a synthetic substance that affects the body’s systems, which its mechanism of action and treatment should be more investigated. MDMA provides an immediate enjoyable feeling by stimulating the release of neurotransmitters, such as dopamine and serotonin in the brain. Unfortunately, abnormal regulation of the brain neurotransmitters, as well as the increased oxidative stress causes damage to the brain neurons after the MDMA exposure. Only a few studies have been done regarding its treatment. Thus, the treatment of MDMA complications should be further explored mainly by targeting its mechanism of action in the neurotransmitter systems. Hence, this study presents a short review regarding the recent findings on the role of neurotransmitters to cause MDMA neurotoxicity. The results will be useful for future research in elucidating the potential treatment based on the targeted mechanisms to treat the neurotoxic effects of MDMA.

The dazzling rise of neurofilaments: Physiological functions and roles as biomarkers

In the last two years, neurofilaments (NFs) have become one of the most blazing topics in clinical neuroscience. NFs are major cytoskeletal constituents of neurons, can be detected in body fluids, and have recently emerged as universal biomarkers of neuronal injury and neurological diseases. This review will examine the evolving landscape of NFs, from their specific cellular functions within neurons to their broad clinical value as biomarkers. Particular attention will be given to the dynamic nature of the NF network and its novel roles in microtubule regulation, neurotransmission, and nanomedicine. Building from the initial evidence of causative mutations in NF genes in Charcot-Marie-Tooth diseases, the latest advances at the frontiers of basic and clinical sciences have expanded the scope and relevance of NFs for human health remarkably and have poised to fuel innovation in cell biology and neuroscience.