Untargeted metabolomic analysis of Rat neuroblastoma cells as a model system to study the biochemical effects of the acute administration of methamphetamine

Methamphetamine is an illicit psychostimulant drug that is linked to a number of diseases of the nervous system. The downstream biochemical effects of its primary mechanisms are not well understood, and the objective of this study was to investigate whether untargeted metabolomic analysis of an in vitro model could generate data relevant to what is already known about this drug. Rat B50 neuroblastoma cells were treated with 1 mM methamphetamine for 48 h, and both intracellular and extracellular metabolites were profiled using gas chromatography–mass spectrometry. Principal component analysis of the data identified 35 metabolites that contributed most to the difference in metabolite profiles. Of these metabolites, the most notable changes were in amino acids, with significant increases observed in glutamate, aspartate and methionine, and decreases in phenylalanine and serine. The data demonstrated that glutamate release and, subsequently, excitotoxicity and oxidative stress were important in the response of the neuronal cell to methamphetamine. Following this, the cells appeared to engage amino acid-based mechanisms to reduce glutamate levels. The potential of untargeted metabolomic analysis has been highlighted, as it has generated biochemically relevant data and identified pathways significantly affected by methamphetamine. This combination of technologies has clear uses as a model for the study of neuronal toxicology

Repetitive low intensity magnetic field stimulation in a neuronal cell line: a metabolomics study

Low intensity repetitive magnetic stimulation of neural tissue modulates neuronal excitability and has promising therapeutic potential in the treatment of neurological disorders. However, the underpinning cellular and biochemical mechanisms remain poorly understood. This study investigates the behavioural effects of low intensity repetitive magnetic stimulation (LI-rMS) at a cellular and biochemical level. We delivered LI-rMS (10 mT) at 1 Hz and 10 Hz to B50 rat neuroblastoma cells in vitro for 10 minutes and measured levels of selected metabolites immediately after stimulation. LI-rMS at both frequencies depleted selected tricarboxylic acid (TCA) cycle metabolites without affecting the main energy supplies. Furthermore, LI-rMS effects were frequency-specific with 1 Hz stimulation having stronger effects than 10 Hz. The observed depletion of metabolites suggested that higher spontaneous activity may have led to an increase in GABA release. Although the absence of organised neural circuits and other cellular contributors (e.g., excitatory neurons and glia) in the B50 cell line limits the degree to which our results can be extrapolated to the human brain, the changes we describe provide novel insights into how LI-rMS modulates neural tissue

The Roles of Opioid Receptors and Agonists in Health and Disease Conditions

The authors graciously acknowledge Queen Margaret University, Edinburgh for the award of the Martlet research Scholarship and the Ahmadu Bello University Zaria-Nigeria for awarding the first author study fellowship to undertake this research studies.Opioid receptors are found in the Central Nervous System (CNS) and are classified as mu (µ), kappa (κ), delta (δ) and sigma (σ) opioid receptors. Opioid receptors belong to the large family of G Protein Coupled Receptors (GPCRs), and have diverse and important physiological roles. The aim of the present review is to discuss the roles played by opioid receptors, their agonists and antagonists in health and disease conditions. Opioid receptors are not uniformly distributed in the CNS and are found in areas concerned with pain, with the highest concentration in the cerebral cortex, followed by the amygdala, septum, thalamus, hypothalamus, midbrain and spinal cord. Activated delta opioid receptors are coupled to Gi1 while activated mu opioid receptors are coupled to Gi3 in neuroblastoma cells. Mu opioid receptors are activated by mu receptor agonists and are coupled through the Gi1 and GoA. Both mu and kappa opioid receptors are coupled via both Gi and Gz and opioid receptors are important targets for thousands of pharmacological agents. GPCRs typically require activation by agonists for their signalling activity to be initiated but some of the GPCRs may display basal or spontaneous signalling activity in the absence of an agonist. The stimulation of these receptors triggers analgesic effects and affects the function of the nervous system, gastrointestinal tract and other body systems. Hundreds of analogs of opioid peptides have been synthesized in an effort to make the compounds more active, selective, and resistant to biodegradation than the endogenous ligands. 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The Effect of Hypoxia on G Protein Coupled (CB1) Receptor Gene Expression in Cortical B50 Neurons in Culture

The authors acknowledge Queen Margaret University, Edinburgh for the award of the Martlet research Scholarship and the Ahmadu Bello University Zaria-Nigeria for awarding the first author study fellowship to undertake this research studies. The authors would like to thank Promega Corporation for generously providing us with free samples and assay kits and reagents. Our special thanks go to Drs Paul Kelly and Linda Ferrington of the Centre for Neuroscience, University of Edinburgh for their help and guidance in RT-PCR technique. Our thanks goes to Dr Elizabeth Fashola- Stone, Technical Manager European collection of cell cultures (ECACC), for providing specialist and technical advice on the use of B50 cells.Hypoxia adversely affects cells and tissues, and neuronal cells in particular have been shown to be more susceptible to the injurious effects of hypoxia in which they may begin to die when oxygen supply is reduced or completely eliminated. Cannabinoid (CB1) receptor agonists have been shown to elicit several Central Nervous System (CNS) effects, mediated via G protein-coupled receptors. The aim of this study was to examine the effect of hypoxia on G protein coupled receptor (CB1) gene expression in cortical neuronal B50 cell lines in culture. The B50 cells were cultured in normoxia (21% O2; 5% CO2) and hypoxia (5% O2; 5% CO2), and were treated with cannabinoid agonists to determine their effects on hypoxia-induced changes. Three cannabinoid agonists [Win55,212-2 mesylate (Win), arachidonoylethanolamide (AEA) and 2- arachidonylglycerol (2-AG)], were administered to the cells as treatment for 48 hours after 48hours of initial culture for a total of 96hours of culture in hypoxic conditions at concentrations of 10, 50 and 100 nM. The levels of G-protein coupled receptor (CB1) mRNAs were assessed using RT-PCR. 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A wide search for obscured active galactic nuclei using XMM-Newton and WISE

Heavily obscured and Compton-thick active galactic nuclei (AGNs) are missing even in the deepest X-ray surveys, and indirect methods are required to detect them. Here we use a combination of the XMM–Newton serendipitous X-ray survey with the optical Sloan Digital Sky Survey (SDSS), and the infrared WISE all-sky survey in order to check the efficiency of the low X-ray-to-infrared luminosity selection method in finding heavily obscured AGNs. We select the sources which are detected in the hard X-ray band (2–8 keV), and also have a redshift determination (photometric or spectroscopic) in the SDSS catalogue. We match this sample with the WISE catalogue, and fit the spectral energy distributions of the 2844 sources which have three, or more, photometric data points in the infrared. We then select the heavily obscured AGN candidates by comparing their 12 μm luminosity to the observed 2–10 keV X-ray luminosity and the intrinsic relation between the X-ray and the mid-infrared luminosities. With this approach, we find 20 candidate heavily obscured AGNs and we then examine their X-ray and optical spectra. Of the 20 initial candidates, we find nine (64 per cent; out of the 14, for which X-ray spectra could be fitted) based on the X-ray spectra, and seven (78 per cent; out of the nine detected spectroscopically in the SDSS) based on the [O III] line fluxes. Combining all criteria, we determine the final number of heavily obscured AGNs to be 12–19, and the number of Compton-thick AGNs to be 2–5, showing that the method is reliable in finding obscured AGNs, but not Compton thick. However, those numbers are smaller than what would be expected from X-ray background population synthesis models, which demonstrates how the optical–infrared selection and the scatter of the Lx-LMIR relation limit the efficiency of the method. Finally, we test popular obscured AGN selection methods based on mid-infrared colours, and find that the probability of an AGN to be selected by its mid-infrared colours increases with the X-ray luminosity. The (observed) X-ray luminosities of heavily obscured AGNs are relatively low (L2−10keV<1044ergs−1), even though most of them are located in the ‘quasi stellar object (QSO) locus’. However, a selection scheme based on a relatively low X-ray luminosity and mid-infrared colours characteristic of QSOs would not select ∼25 per cent of the heavily obscured AGNs of our sample

Toxicological screening and DNA sequencing detects contamination and adulteration in regulated herbal medicines and supplements for diet, weight loss and cardiovascular health

Use of herbal medicines and supplements by consumers to prevent or treat disease, particularly chronic conditions continues to grow, leading to increased awareness of the minimal regulation standards in many countries. Fraudulent, adulterated and contaminated herbal and traditional medicines and dietary supplements are a risk to consumer health, with adverse effects and events including overdose, drug-herb interactions and hospitalisation. The scope of the risk has been difficult to determine, prompting calls for new approaches, such as the combination of DNA metabarcoding and mass spectrometry used in this study. Here we show that nearly 50% of products tested had contamination issues, in terms of DNA, chemical composition or both. Two samples were clear cases of pharmaceutical adulteration, including a combination of paracetamol and chlorpheniramine in one product and trace amounts of buclizine, a drug no longer in use in Australia, in another. Other issues include the undeclared presence of stimulants such as caffeine, synephrine or ephedrine. DNA data highlighted potential allergy concerns (nuts, wheat), presence of potential toxins (Neem oil) and animal ingredients (reindeer, frog, shrew), and possible substitution of bird cartilage in place of shark. Only 21% of the tested products were able to have at least one ingredient corroborated by DNA sequencing. This study demonstrates that, despite current monitoring approaches, contaminated and adulterated products are still reaching the consumer. We suggest that a better solution is stronger pre-market evaluation, using techniques such as that outlined in this study

The Roles of Guanine Nucleotide Binding Proteins in Health and Disease

G-proteins are important mediators of cellular and tissue functions and are characterised by a recognition site for Guanine Triphosphate (GTP), Guanine Diphosphate (GDP) and possess intrinsic GTPase activity. They play important roles in signal transduction responsible for cytoskeletal remodelling, cellular differentiation and vesicular transport. They are made up of three types namely, the small G-proteins, the sensors and the heterotrimeric G-proteins. The G-protein heterotrimers consist of G-alpha (G), G-beta (G$) and G-gamma (G() subunits. Each heterotrimeric G-protein have different subunits and the combination of these subunits define the specific role of each G-protein. The activation of G subunits regulates the activity of effector enzymes and ion channels while G$( subunits function in the regulation of mitogen-activated protein kinase (MAP-kinase) pathway. 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The evolving AGN duty cycle in galaxies since z ∼ 3 as encoded in the X-ray luminosity function

We present a new modeling of the X-ray luminosity function (XLF) of active galactic nuclei (AGNs) out to z ~ 3, dissecting the contributions of main-sequence (MS) and starburst (SB) galaxies. For each galaxy population, we convolved the observed galaxy stellar mass (M sstarf) function with a grid of M sstarf-independent Eddington ratio (λ EDD) distributions, normalized via empirical black hole accretion rate (BHAR) to star formation rate (SFR) relations. Our simple approach yields an excellent agreement with the observed XLF since z ~ 3. We find that the redshift evolution of the observed XLF can only be reproduced through an intrinsic flattening of the λ EDD distribution and with a positive shift of the break λ*, consistent with an antihierarchical behavior. The AGN accretion history is predominantly made by massive (1010 44.36 + 1.28 × (1 + z). We infer that the probability of finding highly accreting (λ EDD > 10%) AGNs significantly increases with redshift, from 0.4% (3.0%) at z = 0.5%–6.5% (15.3%) at z = 3 for MS (SB) galaxies, implying a longer AGN duty cycle in the early universe. Our results strongly favor a M sstarf-dependent ratio between BHAR and SFR, as BHAR/SFR ∝ ${M}_{\star }^{0.73[+0.22,-0.29]}$, supporting a nonlinear BH buildup relative to the host. Finally, this framework opens potential questions on super-Eddington BH accretion and different λ EDD prescriptions for understanding the cosmic BH mass assembly