bluuebunny/crossref_metadata_2025_split huggingface dataset:
Different effects of five dopamine receptor subtypes on nuclear factor‐κB activity in NG108‐15 cells and mouse brain
Authors: Takeuchi Yusuke , Fukunaga Kohji 
Published: July 2010

AbstractWe previously showed that dopamine receptors D1R and D2R expressed in NG108‐15 cells activated protein kinase A and extracellular signal‐regulated kinase (ERK) respectively, resulting in differential activation of nuclear factor (NF)‐κB activity. To investigate whether other dopamine receptor subtypes regulate NF‐κB, we established NG108‐15 cells stably expressing D3R, D4R and D5R (NGD3R, NGD4R and NGD5R). D5R stimulation with SKF 38393 decreased NF‐κB luciferase reporter activity in NGD5R cells, similar to D1R stimulation in NGD1R cells. However, D3R or D4R stimulation with quinpirole showed no change in NF‐κB‐Luci activity, although forskolin‐induced cyclic AMP responsive element‐Luci activation was attenuated by quinpirole treatment in NGD2LR, NGD3R and NGD4R cells. As expected, activation of ERK or serum responsive element‐luciferase reporter not observed following stimulation with quinpirole in D3R‐ or D4R‐expressing cells. We further examined the effects of haloperidol and risperidone, which are typical and atypical antipsychotic drugs respectively, on NF‐κB activity by gel shift assay in mouse frontal cortex. Haloperidol treatment slightly attenuated basal NF‐κB activity. By contrast, risperidone treatment enhanced NF‐κB activity. Taken together, D2R and D1R/D5R had opposite effects on NF‐κB activity in NG108‐15 cells. Risperidone up‐regulated and haloperidol down‐regulated NF‐κB activity in mouse brain. This effect may be related to the atypical antipsychotic properties of risperidone.
Expression of a novel neuropeptide, NVGTLARDFQLPIPNamide, in the larval and adult brain of Drosophila melanogaster
Authors: Verleyen Peter , Baggerman Geert , Wiehart Ursula , Schoeters Eric , Van Lommel Alfons , De Loof Arnold , Schoofs Liliane 
Published: July 2010

AbstractAdvances in mass spectrometry and the availability of genomic databases made it possible to determine the peptidome or peptide content of a specific tissue. Peptidomics by nanoflow capillary liquid chromatography tandem mass spectrometry of an extract of 50 larval Drosophila brains, yielded 28 neuropeptides. Eight were entirely novel and encoded by five not yet annotated genes; only two genes had a homologue in the Anopheles gambiae genome. Seven of the eight peptides did not show relevant sequence homology to any known peptide. Therefore, no evidence towards the physiological role of these ‘orphan’ peptides was available. We identified one of the eight peptides, IPNamide, in an extract of the Drosophila adult brain as well. Next, specific antisera were raised to reveal the distribution pattern of IPNamide and other peptides from the same precursor, in larval and adult brains by means of whole‐mount immunocytochemistry and confocal microscopy. IPNamide immunoreactivity is abundantly present in both stages and a striking similarity was found between the distribution patterns of IPNamide and TPAEDFMRFamide, a member of the FMRFamide peptide family. Based on this distribution pattern, IPNamide might be involved in phototransduction, in processing sensory stimuli, as well as in controlling the activity of the oesophagus.
Signalling pathways for insulin‐like growth factor type 1‐mediated expression of uncoupling protein 3
Authors: Gustafsson Helena , Tamm Christoffer , Forsby Anna 
Published: July 2010

AbstractUncoupling protein 3 (UCP3) is a mitochondrial protein with antioxidant properties and its regulation by factors promoting cell‐survival may be important for protection of, for instance, neurons in states of oxidative stress. In the present study, we investigated regulatory pathways for UCP3 expression mediated by the neuroprotective hormone insulin‐like growth factor type 1 (IGF‐1) in human neuroblastoma SH‐SY5Y cells. Northern blot analysis and RT‐PCR showed that treatment with 10 nm IGF‐1 increased the UCP3 mRNA levels 2.5‐fold after 5 h. Co‐incubation with the phosphatidylinositol 3 (PI3)‐kinase inhibitor LY294002 prohibited IGF‐1‐mediated induction of both UCP3 mRNA and protein in a concentration‐dependent manner, with a complete blockage at 1 μm, as shown by RT‐PCR and western blot analyses. The mitogen‐activated protein (MAP) kinase kinase 1 (MKK1 or MEK) inhibitor PD98059 also decreased the UCP3 mRNA expression at 10 μm, however, this concentration only partly inhibited the protein expression. We conclude that IGF‐1 enhanced UCP3 expression at transcriptional level, primarily through the PI3‐kinase‐dependent pathway and partly through the MAP kinase pathway.
Tumour necrosis factor alpha inhibits purinergic calcium signalling in blood–brain barrier endothelial cells
Authors: Vandamme Wouter , Braet Katleen , Cabooter Liesbet , Leybaert Luc 
Published: July 2010

AbstractThe breaching of the blood–brain barrier is an essential aspect in the pathogenesis of neuroinflammatory diseases, in which tumour necrosis factor alpha (TNF‐α) as well as endothelial calcium ions play a key role. We investigated whether TNF‐α could influence the communication of calcium signals between brain endothelial cells (GP8 and RBE4). Intercellular calcium waves triggered by mechanical stimulation or photoliberation of InsP3 in single cells were significantly reduced in size after TNF‐α exposure (1000 U/mL, 2 and 24 h). Calcium signals are communicated between cells by means of gap junctional and paracrine purinergic signalling. TNF‐α significantly inhibited gap junctional coupling, stimulated the basal release of ATP, and dose‐dependently blocked the triggered component of ATP release. The cytokine displayed similar effects on the uptake of a fluorescent reporter dye into the cells. Previous work with connexin mimetic peptides demonstrated that the triggered ATP release in these cells is connexin‐related; these peptides did, however, not influence the elevated basal ATP release caused by TNF‐α. We conclude that TNF‐α depresses calcium signal communication in blood–brain barrier endothelial cells, by reducing gap junctional coupling and by inhibiting triggered ATP release. The cytokine thus inhibits connexin‐related communication pathways like gap junctions and connexin hemichannels.
Phosphatidylinositol 3′‐OH kinase and protein kinase A pathways mediate the anti‐apoptotic effect of pituitary adenylyl cyclase‐activating polypeptide in cultured cerebellar granule neurons: modulation by ethanol
Authors: Bhave Sanjiv V. , Hoffman Paula L. 
Published: July 2010

AbstractCerebellar granule neurons cultured in the presence of 5 mmKCl undergo spontaneous apoptosis, which is reduced by exposure to pituitary adenylyl cyclase‐activating polypeptide (PACAP). Previous work has suggested roles for the cyclic AMP/PKA and MAP kinase signaling pathways in the anti‐apoptotic effect of PACAP. In the present study, the use of specific inhibitors confirmed the role of the cyclic AMP/PKA pathway, and also demonstrated a role for the phosphatidylinositol 3′‐OH kinase (PI 3‐kinase) neuroprotective pathway in the action of PACAP. Ethanol exposure accelerates the anti‐apoptotic effect of PACAP by a mechanism that involves the PKA and PI‐3 kinase pathways. The results demonstrate that ethanol canincrease neuroprotectioninduced by PACAP. As previous work has shown that ethanol canincrease apoptosisof cerebellar granule neurons by inhibiting the protective effect of agents such as NMDA or IGF‐1, the overall effect of ethanol on cerebellar neuron apoptosis during development may reflect the balance between inhibition and enhancement of the actions of various endogenous neuroprotective agents.
Identification of differentially regulated transcripts in mouse striatum following methamphetamine treatment – an oligonucleotide microarray approach
Authors: Thomas David M. , Francescutti‐Verbeem Dina M. , Liu Xiuli , Kuhn Donald M. 
Published: July 2010

AbstractMethamphetamine is an addictive drug of abuse that can produce neurotoxic effects in dopamine nerve endings of the striatum. The purpose of this study was to identify new genes that may play a role in the highly complex cascade of events associated with methamphetamine intoxication. Using Affymetrix oligonucleotide arrays, 12 488 genes were simultaneously interrogated and there were 152 whose expression levels were changed following methamphetamine treatment. The genes are grouped into broad functional categories with inflammatory/immune response elements, receptor/signal transduction components and ion channel/transport proteins among the most populated. Many genes within these categories can be linked to ion regulation and apoptosis, both of which have been implicated in methamphetamine toxicity, and numerous factors associated with microglial activation emerged with significant changes in expression. For example, brain‐derived neurotrophic factor (BDNF), chemokine (C‐C) receptor 6 (CCr6) and numerous chemokine transcripts were increased or decreased in expression more than 2.8‐fold. These results point to activated microglia as a potential source of the reactive oxygen/nitrogen species and cytokines that have been previously associated with methamphetamine toxicity and other neurotoxic conditions.
Hypoxia increases calcium flux through cortical neuron glutamate receptors via protein kinase C
Authors: Bickler P. E. , Fahlman C. S. , Ferriero D. M. 
Published: July 2010

AbstractThe effects of 30 s to 10 min hypoxia (PO2−10 mmHg) on glutamate receptor activity were studied in murine cortical neurons. Receptor activity was assessed as a rise in intracellular calcium concentration ([Ca2+]i) following a 10 s application of 1 mmglutamate or 100 µmN‐methy‐d‐aspartate (NMDA) in the presence of 0.1 mmMg2+and 10 µmglycine. Change in [Ca2+]ielicited by glutamate increased 26% (n = 192,p < 0.001) and that to NMDA by 74% (n = 9,p < 0.01) during a 100‐s period of hypoxia. After 10 min hypoxia, responses to glutamate were 62% smaller than those in normoxia, with increased basal intracellular [Ca2+]ipredicting reduced receptor activity. When neurons were exposed to NMDA after 10 min of hypoxia, [Ca2+]iincreases were 12% smaller than after 100 s hypoxia, but still 53% larger than in oxygenated neurons (n = 9,p = 0.01). Neurons expressed relatively similar amounts of NR2A, ‐B, ‐C, and ‐D subunits. The phosphorylation of NMDA NR1 subunits increased during hypoxia. Pre‐treatment of neurons with a protein kinase C (PKC) inhibitor (chelerythrine, 10 µm) prevented increases inN‐methy‐d‐aspartate receptor (NMDAR) activity during hypoxia and reduced the phosphorylation of NR1 subunits. These results suggest that enhancement of glutamate receptor activity during the first minutes of hypoxia is mediated by phosphorylation of NMDARs by PKC and that other mechanisms, possibly involving intracellular calcium, limit glutamate receptor‐mediated calcium influx during longer periods of hypoxia.
Stimulus‐specific plasticity of prefrontal cortex dopamine neurotransmission
Authors: Jackson Mark E. , Moghaddam Bita 
Published: July 2010

AbstractFuture planning and behavioral modification is thought to require experience‐dependent plasticity in neuronal circuits involving the prefrontal cortex, nucleus accumbens and amygdala. Dopamine has been implicated in such plasticity; however, the nature of the adaptive response of dopamine systems to emotionally salient experiences is poorly understood. We determined whether the dopaminergic response to a given stimulus changes after the first exposure to that stimulus and whether this alteration is stimulus specific. Dopamine release was measured in the prefrontal cortex and the nucleus accumbens in response to two aversive but qualitatively distinct stimuli, physical restraint and electrical microstimulation of basolateral amygdala. In the prefrontal cortex, the first exposure to restraint or amygdala stimulation produced similar increases in dopamine release. The second exposure to restraint resulted in an attenuated response (− 36%) whereas the second exposure to amygdala stimulation produced a potentiated response (+ 110%). Cross‐modal potentiation of response occurred with both stimuli. These adaptive changes were specific to the prefrontal cortex and were not observed in the nucleus accumbens. These findings demonstrate that prefrontal cortical dopamine output adapts after a single exposure to stimuli with emotional salience. The direction of this adaptation, however, is not uniform and depends on the nature of the stimulus.
Glycogen metabolism in the rat retina
Authors: Coffe Víctor , Carbajal Raymundo C. , Salceda Rocío 
Published: July 2010

AbstractIt has been reported that glycogen levels in retina vary with retinal vascularization. However, the electrical activity of isolated retina depends on glucose supply, suggesting that it does not contain energetic reserves. We determined glycogen levels and pyruvate and lactate production under various conditions in isolated retina. Ex vivo retinas from light‐ and dark‐adapted rats showed values of 44 ± 0.3 and 19.5 ± 0.4 nmol glucosyl residues/mg protein, respectively. The glycogen content of retinas from light‐adapted animals was reduced by 50% when they were transferred to darkness. Glycogen levels were low in retinas incubated in glucose‐free media and increased in the presence of glucose. The highest glycogen values were found in media containing 20 mm of glucose. A rapid increase in lactate production was observed in the presence of glucose. Surprisingly, glycogen levels were the lowest and lactate production was also very low in the presence of 30 mm glucose. Our results suggest that glycogen can be used as an immediate accessible energy reserve in retina. We speculate on the possibility that gluconeogenesis may play a protective role by removal of lactic acid.
Microglia/macrophage‐specific protein Iba1 binds to fimbrin and enhances its actin‐bundling activity
Authors: Ohsawa Keiko , Imai Yoshinori , Sasaki Yo , Kohsaka Shinichi 
Published: July 2010

AbstractIonized calcium binding adaptor molecule 1 (Iba1) is a microglia/macrophage‐specific calcium‐binding protein. Iba1 has the actin‐bundling activity and participates in membrane ruffling and phagocytosis in activated microglia. In order to understand the Iba1‐related intracellular signalling pathway in greater detail, we employed a yeast two‐hybrid screen to isolate an Iba1‐interacting molecule and identified another actin‐bundling protein, L‐fimbrin. In response to stimulation, L‐fimbrin accumulated and co‐localized with Iba1 in membrane ruffles induced by M‐CSF‐stimulation and phagocytic cups formed by IgG‐opsonized beads in microglial cell line MG5. L‐fimbrin was shown to associate with Iba1 in cell lysate of COS‐7 expressing L‐fimbrin and Iba1. By using purified proteins, direct binding of Iba1 to L‐fimbrin was demonstrated by immunoprecipitation, glutathione S‐transferase pull‐down assays and ligand overlay assays. The binding of Iba1 was also found to increase the actin‐bundling activity of L‐fimbrin. These results indicate that Iba1 forms complexes with L‐fimbrin in membrane ruffles and phagocytic cups, and suggest that Iba1 co‐operates with L‐fimbrin in modulating actin reorganization to facilitate cell migration and phagocytosis by microglia.
Enhanced morphine withdrawal and µ‐opioid receptor G‐protein coupling in A2Aadenosine receptor knockout mice
Authors: Bailey Alexis , Davis Lianne , Lesscher Heidi M. B. , Kelly Mary D. W. , Ledent Catherine , Hourani Susanna M. O. , Kitchen Ian 
Published: July 2010

AbstractMuch evidence supports the hypothesis that A2Aadenosine receptors play an important role in the expression of morphine withdrawal and that the dopaminergic system might also be involved. We have evaluated morphine withdrawal signs in wild‐type and A2Areceptor knockout mice and shown a significant enhancement in some withdrawal signs in the knockout mice. In addition, µ‐opioid and dopamine D2receptor autoradiography, as well as µ‐opioid receptor‐stimulated guanylyl 5′‐[γ‐[35S]thio]‐triphosphate ([35S]GTPγS) autoradiography was carried out in brain sections of withdrawn wild‐type and knockout mice. No significant changes in D2and µ‐opioid receptor binding were observed in any of the brain regions analysed. However, a significant increase in the level of µ receptor‐stimulated [35S]GTPγS binding was observed in the nucleus accumbens of withdrawn knockout mice. These data indicate that the A2Areceptor plays a role in opioid withdrawal related to functional receptor activation.
Adaptive responses in hypothalamic neuropeptide Y in the face of prolonged high‐fat feeding in the rat
Authors: Hansen Michelle J. , Jovanovska Valentina , Morris Margaret J. 
Published: July 2010

AbstractWhile a dysregulation in neuropeptide Y (NPY) signaling has been described in rodent models of obesity, few studies have investigated the time‐course of changes in NPY content and responsiveness during development of diet‐induced obesity. Therefore we investigated the effect of differing lengths (2–17 weeks) of high‐fat diet on hypothalamic NPY peptide content, release and NPY‐induced hyperphagia. Male Sprague–Dawley rats (211 ± 3 g) were fed either a high‐fat diet (30% fat) or laboratory chow (5% fat). Animals were implanted with intracerebroventricular cannulae to investigate feeding responses to NPY (0.5 nmol, 1 nmol) after 4 or 12 weeks of diet. At the earlier stage of obesity, NPY‐induced hyperphagia was not altered; however, animals maintained on the high‐fat diet for the longer duration were hyper‐responsive to NPY, compared to chow‐fed control rats (p < 0.05). Overall, hypothalamic NPY peptide content tended to be decreased from 9 to 17 weeks of diet (p < 0.05). Total hypothalamic NPY content was negatively correlated with plasma leptin concentration (p < 0.05), suggesting the hypothalamic NPY system remains responsive to leptin's inhibitory signal. In addition, hypothalamic NPY overflow was significantly reduced in high‐fat fed animals (p < 0.05). Together these results suggest a reduction in hypothalamic NPY activity in high‐fat fed animals, perhaps in an attempt to restore energy balance.
Down‐regulation of rat brain adenosine A1receptors at the end of pregnancy
Authors: León David , Albasanz José Luis , Fernández Mercedes , Ruíz Maria Angeles , Martín Mairena 
Published: July 2010

AbstractThe status of the adenosine A1receptor/adenylyl cyclase (A1R/AC) transduction pathway in rat brain was analysed at the end of pregnancy using different approaches. Pregnancy at term caused a significant decrease in the Bmaxvalue obtained by saturation binding assays using [3H]DPCPX as radioligand, suggesting a down‐regulation of adenosine A1receptor. Moreover, A1receptor immunodetection in pregnant rat membranes and the level of mRNA coding A1receptor were significantly decreased. This loss of A1receptor was associated with a significant increase in receptor affinity, since the KDvalue from the [3H]DPCPX saturation curve and Kifor N6‐cyclohexyladenosine (CHA) were decreased in pregnant rats. Surprisingly, CHA‐mediated inhibition of adenylyl cyclase was increased, reflecting enhanced receptor responsiveness. On the other hand, immunoblotting of different αGi‐protein isoforms revealed a significant increase in αGi3level in membranes from pregnant rats. Pre‐incubation of membranes with anti‐αGi3antibody blocked the guanosine triphosphate (GTP) or CHA inhibitory effect on adenylyl cyclase in both pregnant and non‐pregnant rats, pointing to αGi3as the main isoform involved in the A1receptor response. These results suggest that, at the end of pregnancy, there is a down‐regulation of adenosine A1 receptors counterbalanced with a strengthened functionality, probably due to an increase in both αGi3protein and receptor affinity.
Cell type‐dependent recruitment of trichostatin A‐sensitive repression of the human 5‐HT1A receptor gene
Authors: Lemonde Sylvie , Rogaeva Anastasia , Albert Paul R. 
Published: July 2010

AbstractRegulation of serotonin (5‐HT)1A receptor expression in brain is implicated in mood disorders such as depression and anxiety. Transcriptional activity of the human 5‐HT1A receptor gene was strongly repressed by a negative regulatory region containing a consensus repressor element‐1 (RE‐1) and two copies of the dual repressor element (DRE) identified in the rat 5‐HT1A receptor gene. REST/NRSF, a silencer of neuronal genes, bound the 5‐HT1A RE‐1 and repressed the 5‐HT1A promoter. Inactivation of RE‐1 completely abolished REST‐mediated repression, but resulted in only partial (15–50%) de‐repression of basal 5‐HT1A promoter activity. The human 5‐HT1A DRE sequences bound specifically to the novel repressor Freud‐1 (5′repressor element under dual repression binding protein‐1) and conferred repressor activity at 5‐HT1A or SV40 promoters. In 5‐HT1A‐negative cells [L6, human embryonic kidney (HEK) 293], the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) abolished repression mediated by both RE‐1/REST and DRE/Freud‐1, and induced almost complete de‐repression of the 5‐HT1A gene. By contrast, in 5‐HT1A‐expressing neuronal cells (RN46A, SN‐48) TSA blocked RE‐1/REST repression, but did not affect DRE/Freud‐1‐mediated repression. Thus in contrast to REST, Freud‐1 mediates HDAC‐independent repression of the 5‐HT1A receptor promoter in neuronal 5‐HT1A‐positive cells, suggesting that HDAC recruitment might influence neuron‐specific gene expression by further silencing expression in non‐neuronal tissue.
Regulation of β‐amyloid precursor protein expression by brain‐derived neurotrophic factor involves activation of both the Ras and phosphatidylinositide 3‐kinase signalling pathways
Authors: Ruiz‐León Yolanda , Pascual Angel 
Published: July 2010

AbstractBrain‐derived neurotrophic factor (BDNF) stimulates β‐amyloid precursor protein (APP) promoter activity by a Ras‐dependent mechanism in TrkB‐expressing SH‐SY5Y cells. To determine the signalling pathways involved in the BDNF‐induced response, we have analysed the ability of TrkB mutated forms to mediate promoter stimulation. Brain‐derived neurotrophic factor causes a significant induction of promoter activity and mutation K540R in the active site of TrkB completely abolishes the neurotrophin‐induced response. A substitution of the Y484 residue by phenylalanine, which blocks binding of Shc, reduces the activation of APP promoter by BDNF by approximately 50% whereas mutation Y785P, which blocks binding of phospholipase C gamma, does not affect the response. In addition, the phosphatidylinositide 3‐kinase (PI3K)‐specific inhibitors wortmannin and LY294002 reduced BDNF‐induced activation. In agreement with a participation of both Ras/MAPK‐ and PI3K/Akt‐mediated mechanisms, transient expression of constitutive active forms of Ras, PI3K and other components of both signalling pathways led to a significant increase of APP promoter activity. Furthermore, the stimulation of the APP promoter by BDNF was completely precluded by expression of dominant‐negative forms of Ras and PI3K effectors. Taken together, our results suggest that simultaneous activation of at least two signalling pathways, Ras/MAPK and PI3K/Akt, is necessary to mediate a full activation of the APP promoter by BDNF.