Search results for "IPA"
showing 10 items of 5795 documents
Activation of phospholipases C and D by the novel metabotropic glutamate receptor agonist tADA.
1997
Abstract In hippocampal slices taken from 8-day-old rats, trans-azetidine-2,4-dicarboxylic acid (tADA), a novel glutamatergic agonist acting preferentially at class I mGluR receptors, activates phosphoinositide and phosphatidylcholine hydrolysis with widely different potencies. Inositol phosphate formation was maximally increased at 10 μM tADA ( ec 50: 1.2 μM), while phospholipase D activation was observed at a tADA concentration of 1 mM. This is the first report of a tADA-induced phospholipase D activity. © 1997 Elsevier Science Ltd. All rights reserved.
Exposure to gp120 of HIV-1 induces an increased release of arachidonic acid in rat primary neuronal cell culture followed by NMDA receptor-mediated n…
1995
After incubation of highly enriched neurons from rat cerebral cortex with the HIV-1 coat protein gp120 for 18 h, cells showed fragmentation of DNA at internucleosomal linkers followed by NMDA receptor-mediated neurotoxicity. We report that in response to exposure to gp120 cells react with an increased release of arachidonic acid (AA) via activation of phospholipase A2. This process was not inhibited by NMDA receptor antagonists. To investigate the role of AA on the sensitivity of the NMDA receptor towards its agonist, low concentrations of NMDA were co-administered with AA. This condition enhanced the NMDA-mediated cytotoxicity. Administration of mepacrine reduced cytotoxicity caused by gp1…
Adrenergic activation of phospholipase D in primary rat astrocytes.
1996
Phospholipase D (PLD) activity was investigated in astrocytes prepared from newborn rat cerebral cortex using the transphosphatidylation assay. Basal PLD activity was measurable and was found to be enhanced by ATP, carbachol and noradrenaline. The activation by noradrenaline (EC50, 0.68 microM) was mimicked by methoxamine (EC50, 65 microM), an alpha 1-specific adrenergic agonist, and was inhibited by prazosine, an alpha 1-specific adrenergic antagonist. Clonidin, an alpha 2-adrenergic agonist, slightly lowered PLD activity whereas beta-adrenergic drugs were without effect. Experiments with mitogens indicate that PLD activation in astrocytes may be involved in the control of astrocytic cell …
Ontogenetic and Pharmacological Studies on Metabotropic Glutamate Receptors Coupled to Phospholipase D Activation
1997
The present study was aimed at characterizing the metabotropic receptor subtype which is involved in the activation of phospholipase D (PLD) by glutamate in rat hippocampal slices. We first observed that the ontogenetic profile of glutamate-induced hydrolysis of phosphoinositides and of phosphatidylcholine was strikingly similar. Both pathways were significantly activated by glutamate in tissue taken from 3-, 8- and 15-day old rats, but not in adult rats. PLD activation was strongest in slices taken from 8-day old rats. At this age, quisqualate had a higher potency for PLD activation (EC50: 0.6 microM) than 1S,3R-ACPD (EC50: 16 microM) and DHPG, a specific activator of group I mGluR, was a …
Ionotrophic 5-hydroxytryptamine type 3 receptor activates the protein kinase C-dependent phospholipase D pathway in human T-cells
1999
The present study was undertaken to investigate the role of the 5-hydroxytryptamine (5-HT) ionotrophic receptor 5-HT3 in the activation of human Jurkat T-cells. 5-HT and 2-methyl-5-HT (2Me-5-HT), an agonist of the 5-HT3 receptor, induced increases in intracellular free Na+ concentrations, [Na+]i, via opening of the ionotrophic receptor in these cells. These two serotonergic (5-hydroxytryptaminergic) agents potentiated phytohaemagglutinin (PHA)-induced T-cell activation. However, they failed to potentiate dioctanoglycerol-plus-ionomycin-stimulated T-cell blastogenesis. Interestingly, an inhibitor of protein kinase C (PKC), GF 109203X, curtailed significantly 5-HT and 2Me-5-HT-potentiated T-c…
Associations between personality, sports participation and athletic success. A comparison of Big Five in sporting and non-sporting adults
2018
Abstract The present study investigates whether the Big Five personality traits are different among diverse sports populations. A sample of 881 male athletes and non-athletes completed a self-report questionnaire measuring their personality traits. The Exploratory Structure Equation Modeling (ESEM) approach is adopted to test measurement invariance and mean differences among groups. The results indicate that athletes who had experienced the most success in their sport scored higher than non-athletes in each personality dimension of the Big Five, with the exception of openness, while less successful athletes scored higher than non-athletes only in extraversion and agreeableness. The more suc…
Air quality assessment via functional principal component analysis
2009
The knowledge of the global urban air quality situation represents the first step to face air pollution issues. For the last decades many urban areas can rely on a monitoring network, recording hourly data for the main pollutants. Such data need to be aggregated according to different dimensions, such as time, space and type of pollutant, in order to provide a synthetic air quality index which takes into account interactions among pollutants and correlation among monitoring sites.This paper focuses on Functional Principal Component techniques for the statistical analysis of a set of environmental data x(spt), where s stands for the monitoring site, p for the pollutant and t for time, usuall…
Association between the PNPLA3 (rs738409 C>G) variant and hepatocellular carcinoma: Evidence from a meta-analysis of individual participant data
2014
The incidence of hepatocellular carcinoma (HCC) is increasing in Western countries. Although several clinical factors have been identified, many individuals never develop HCC, suggesting a genetic susceptibility. However, to date, only a few single-nucleotide polymorphisms have been reproducibly shown to be linked to HCC onset. A variant (rs738409 C>G, encoding for p.I148M) in the PNPLA3 gene is associated with liver damage in chronic liver diseases. Interestingly, several studies have reported that the minor rs738409[G] allele is more represented in HCC cases in chronic hepatitis C (CHC) and alcoholic liver disease (ALD). However, a significant association with HCC related to CHC has not b…
Relative principal congruences in congruence-modular quasivarieties
1998
The problem of definability of relative principal congruences in relatively congruence modular (RCM) quasivarieties is investigated. The RCM quasivarieties are characterized in terms of parameterized families of finite sets of pairs of terms which define relative principal congruences.