706 research outputs found

    Hippocampal long-term potentiation is disrupted during expression and extinction but is restored after reinstatement of morphine place preference

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    Learned associations between environmental cues and morphine use play an important role in the maintenance and/or relapse of opioid addiction. Although previous studies suggest that context-dependent morphine treatment alters glutamatergic transmission and synaptic plasticity in the hippocampus, their role in morphine conditioned place preference (CPP) and reinstatement remains unknown. We investigated changes in synaptic plasticity and NMDAR expression in the hippocampus after the expression, extinction, and reinstatement of morphine CPP. Here we report that morphine CPP is associated with increased basal synaptic transmission, impaired hippocampal long-term potentiation (LTP), and increased synaptic expression of the NR1 and NR2b NMDAR subunits. Changes in synaptic plasticity, synaptic NR1 and NR2b expression, and morphine CPP were absent when morphine was not paired with a specific context. Furthermore, hippocampal LTP was impaired and synaptic NR2b expression was increased after extinction of morphine CPP, indicating that these alterations in plasticity may be involved in the mechanisms underlying the learning of drug–environment associations. After extinction of morphine CPP, a priming dose of morphine was sufficient to reinstate morphine CPP and was associated with LTP that was indistinguishable from saline control groups. In contrast, morphine CPP extinguished mice that received a saline priming dose did not show CPP and had disrupted hippocampal LTP. Finally, we found that reinstatement of morphine CPP was prevented by the selective blockade of the NR2b subunit in the hippocampus. Together, these data suggest that alterations in synaptic plasticity and glutamatergic transmission play an important role in the reinstatement of morphine CPP

    Evaluation of Renoprotective Effect of Lipoic Acid and Bosentan Against Diclofenac-Induced Acute Renal Failure

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    Acute renal failure also known as acute kidney injury (AKI) is a complex health condition related to significant morbidity and mortality. In hospitalized patients, around 19-33 percent of AKI episodes are linked to drug induced nephrotoxicity. Although considered safe, NSAIDs such as diclofenac have gained special attention over the past few years due to the potential risk of renal injury. The direct effect of diclofenac-induced renal injury depends on targeting the mitochondria in kidney tissue, and formation of reactive oxygen species (ROS) resulting in oxidative stress. Secondly, diclofenac inhibit renal prostaglandin production, limiting renal afferent arteriole vasodilation, increasing afferent resistance; thus decreasing the glomerular capillary pressure below normal values and glomerular filtration rate will decrease resulting in AKI. Alpha-Lipoic acid (ALA) has beneficial effects in prevention or relief of symptoms of oxidative stress- related diseases, as it acts as antioxidant and anti-inflammatory micronutrient. Bosentan is a competitive antagonist with dual endothelin-1 receptors, as renal vascular ET-1 system is upregulated under many pathophysiological situations. In present study, we investigated the effect of lipoic acid and bosentan in diclofenac induced acute renal failure in male rats. We observed that diclofenac increased serum levels of urea, creatinine, malondialdehyde, KIM-1, TGFβ1 and fibronectin significantly (p>0.05) in the induction group compared to control group. While, SOD significantly (p>0.05) reduced in the induction group compared to control group. Both of lipoic acid and bosentan alone didn’t significantly protect against diclofenac induced AKI. However, the combination group showed a significant protection against AKI. Pearson correlation analysis showed a significant positive correlation between (urea and KIM-1) and between (creatinine and KIM-1) (r2=0.792 and r2=0.677 respectively). Furthermore, there was a significant positive correlation between fibronectin and urea (r2= 0.498, p>0.01) and fibronectin and creatinine (r2=0.356, p>0.05). Interestingly, KIM-1 showed a significant positive correlation with fibronectin (r2=0.536, p>0.01). ROC curve test was performed for KIM-1 and fibronectin biomarkers. The AUC for KIM-1 was 0.986 and for fibronectin was 0.829. We concluded that combination therapy of lipoic acid and bosentan showed a significant protective effect against diclofenac-induced AKI. In addition, fibronectin could be a promising biomarker for detection and diagnosis of acute kidney injury. Key words: Diclofenac, oxidative stress, alpha- lipoic acid, endothelin-1, bosenta

    DHA supplementation during pregnancy does not reduce BMI or body fat mass in children: follow-up of the DHA to Optimize Mother Infant Outcome randomized controlled trial

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    First published March 30, 2016The omega-3 (n-3) long-chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) has proven effective at reducing fat storage in animal studies. However, a systematic review of human trials showed a lack of quality data to support or refute this hypothesis.We sought to determine whether maternal DHA supplementation during the second half of pregnancy results in a lower body mass index (BMI) and percentage of body fat in children.We conducted a follow-up at 3 and 5 y of age of children who were born to mothers enrolled in the DOMInO (DHA to Optimize Mother Infant Outcome) double-blind, randomized controlled trial, in which women with a singleton pregnancy were provided with DHA-rich fish-oil capsules (800 mg DHA/d) or vegetable-oil capsules (control group) in the second half of pregnancy. Primary outcomes were the BMIzscore and percentage of body fat at 3 and 5 y of age. Potential interactions between prenatal DHA and the peroxisome proliferator-activated receptor-γ (PPARγ) genotype as a measure of the genetic predisposition to obesity were investigated.A total of 1614 children were eligible for the follow-up. Parent or caregiver consent was obtained for 1531 children (95%), and these children were included in the analysis. BMIzscores and percentages of body fat of children in the DHA group did not differ from those of children in the control group at either 3 y of age [BMIzscore adjusted mean difference: 0.03 (95% CI: -0.07, 0.13;P= 0.61); percentage of body fat adjusted mean difference: -0.26 (95% CI: -0.99, 0.46;P= 0.47)] or 5 y of age [BMIzscore adjusted mean difference: 0.02 (95% CI: -0.08, 0.12;P= 0.66); percentage of body fat adjusted mean difference: 0.11 (95% CI: -0.60, 0.82;P= 0.75)]. No treatment effects were modified by thePPARγgenotype of the child.Independent of a genetic predisposition to obesity, maternal intake of DHA-rich fish oil during the second half of pregnancy does not affect the growth or body composition of children at 3 or 5 y of age. This trial was registered atwww.anzctr.org.auas ACTRN1260500056906 and ACTRN12611001127998.Beverly S Muhlhausler, Lisa N Yelland, Robyn McDermott, Linda Tapsell, Andrew McPhee, Robert A Gibson, and Maria Makride

    Alternative exon splicing and differential expression in pancreatic islets reveals candidate genes and pathways implicated in early diabetes development

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    Type 2 diabetes (T2D) has a strong genetic component. Most of the gene variants driving the pathogenesis of T2D seem to target pancreatic β-cell function. To identify novel gene variants acting at early stage of the disease, we analyzed whole transcriptome data to identify differential expression (DE) and alternative exon splicing (AS) transcripts in pancreatic islets collected from two metabolically diverse mouse strains at 6 weeks of age after three weeks of high-fat-diet intervention. Our analysis revealed 1218 DE and 436 AS genes in islets from NZO/Hl vs C3HeB/FeJ. Whereas some of the revealed genes present well-established markers for β-cell failure, such as Cd36 or Aldh1a3, we identified numerous DE/AS genes that have not been described in context with β-cell function before. The gene Lgals2, previously associated with human T2D development, was DE as well as AS and localizes in a quantitative trait locus (QTL) for blood glucose on Chr.15 that we reported recently in our N2(NZOxC3H) population. In addition, pathway enrichment analysis of DE and AS genes showed an overlap of only half of the revealed pathways, indicating that DE and AS in large parts influence different pathways in T2D development. PPARG and adipogenesis pathways, two well-established metabolic pathways, were overrepresented for both DE and AS genes, probably as an adaptive mechanism to cope for increased cellular stress. Our results provide guidance for the identification of novel T2D candidate genes and demonstrate the presence of numerous AS transcripts possibly involved in islet function and maintenance of glucose homeostasis

    Flexible Near-Field Wireless Optoelectronics as Subdermal Implants for Broad Applications in Optogenetics

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    In vivo optogenetics provides unique, powerful capabilities in the dissection of neural circuits implicated in neuropsychiatric disorders. Conventional hardware for such studies, however, physically tethers the experimental animal to an external light source, limiting the range of possible experiments. Emerging wireless options offer important capabilities that avoid some of these limitations, but the current size, bulk, weight, and wireless area of coverage is often disadvantageous. Here, we present a simple but powerful setup based on wireless, near-field power transfer and miniaturized, thin, flexible optoelectronic implants, for complete optical control in a variety of behavioral paradigms. The devices combine subdermal magnetic coil antennas connected to microscale, injectable light-emitting diodes (LEDs), with the ability to operate at wavelengths ranging from UV to blue, green-yellow, and red. An external loop antenna allows robust, straightforward application in a multitude of behavioral apparatuses. The result is a readily mass-producible, user-friendly technology with broad potential for optogenetics applications.114419Ysciescopu

    Diet-induced gene expression of isolated pancreatic islets from a polygenic mouse model of the metabolic syndrome

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    AIMS/HYPOTHESIS: Numerous new genes have recently been identified in genome-wide association studies for type 2 diabetes. Most are highly expressed in beta cells and presumably play important roles in their function. However, these genes account for only a small proportion of total risk and there are likely to be additional candidate genes not detected by current methodology. We therefore investigated islets from the polygenic New Zealand mouse (NZL) model of diet-induced beta cell dysfunction to identify novel genes and pathways that may play a role in the pathogenesis of diabetes. METHODS: NZL mice were fed a diabetogenic high-fat diet (HF) or a diabetes-protective carbohydrate-free HF diet (CHF). Pancreatic islets were isolated by laser capture microdissection (LCM) and subjected to genome-wide transcriptome analyses. RESULTS: In the prediabetic state, 2,109 islet transcripts were differentially regulated (>1.5-fold) between HF and CHF diets. Of the genes identified, 39 (e.g. Cacna1d, Chd2, Clip2, Igf2bp2, Dach1, Tspan8) correlated with data from the Diabetes Genetics Initiative and Wellcome Trust Case Control Consortium genome-wide scans for type 2 diabetes, thus validating our approach. HF diet induced early changes in gene expression associated with increased cell-cycle progression, proliferation and differentiation of islet cells, and oxidative stress (e.g. Cdkn1b, Tmem27, Pax6, Cat, Prdx4 and Txnip). In addition, pathway analysis identified oxidative phosphorylation as the predominant gene-set that was significantly upregulated in response to the diabetogenic HF diet. CONCLUSIONS/INTERPRETATION: We demonstrated that LCM of pancreatic islet cells in combination with transcriptional profiling can be successfully used to identify novel candidate genes for diabetes. Our data strongly implicate glucose-induced oxidative stress in disease progression

    Valproic acid influences the expression of genes implicated with hyperglycaemia-induced complement and coagulation pathways

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    Because the liver plays a major role in metabolic homeostasis and secretion of clotting factors and inflammatory innate immune proteins, there is interest in understanding the mechanisms of hepatic cell activation under hyperglycaemia and whether this can be attenuated pharmacologically. We have previously shown that hyperglycaemia stimulates major changes in chromatin organization and metabolism in hepatocytes, and that the histone deacetylase inhibitor valproic acid (VPA) is able to reverse some of these metabolic changes. In this study, we have used RNA-sequencing (RNA-seq) to investigate how VPA influences gene expression in hepatocytes. Interesting, we observed that VPA attenuates hyperglycaemia-induced activation of complement and coagulation cascade genes. We also observe that many of the gene activation events coincide with changes to histone acetylation at the promoter of these genes indicating that epigenetic regulation is involved in VPA action11CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP304668/2014-12010/50015-6; 2012/03238-5; 2014/10198-5; 2015/10356-2NHMRC; International Joint Program. Professor Sam El-Osta is a National Health and Medical Research Council; Senior Research Fello
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