Search results for "TRANSPORTER"
showing 10 items of 676 documents
In situ kinetic modelling of intestinal efflux in rats: functional characterization of segmental differences and correlation with in vitro results.
2007
The objective was to devise and apply a novel modelling approach to combine segmental in situ rat perfusion data and in vitro cell culture data, in order to elucidate the contribution of efflux in drug absorption kinetics. The fluoroquinolone CNV97100 was used as a model P-gp substrate. In situ intestinal perfusion was performed in rat duodenum, jejunum, ileum and colon to measure the influence of P-gp expression on efflux. Inhibition studies of CNV97100 were performed in the presence of verapamil, quinidine, cyclosporin A and p-aminohippuric acid. Absorption/efflux parameters were modelled simultaneously, using data from both in situ studies as well as in vitro studies. The maximal efflux …
Profile of P-glycoprotein distribution in the rat and its possible influence on the salbutamol intestinal absorption process.
2004
8 pages, 2 figures, 2 tables.--PMID: 15124220 [PubMed]
Na+ dependent glutamate transporters (EAAT1, EAAT2, and EAAT3) in primary astrocyte cultures: effect of oxidative stress.
2001
Abstract The Na + -dependent l -glutamate transporters EAAT1(GLAST), EAAT2 (GLT-1) and EAAT3 (EAAC1) are expressed in primary astrocyte cultures, showing that the EAAT3 transporter is not neuron-specific. The presence of these three transporters was evaluated by RT–PCR, immunoblotting, immunocytochemical techniques, and transport activity. When primary astrocyte cultures were incubated with l -buthionine-( S , R )-sulfoximine (BSO), a selective inhibitor of γ-glutamylcysteine synthetase, the GSH concentration was significantly lower than in control cultures, but the expression and amount of protein of EAAT1, EAAT2 and EAAT3 and transport of l -glutamate was unchanged. Oxidative stress was c…
Improving extracellular vesicles visualization: From static to motion
2020
AbstractIn the last decade, extracellular vesicles (EVs) have become a hot topic. The findings on EVs content and effects have made them a major field of interest in cancer research. EVs, are able to be internalized through integrins expressed in parental cells, in a tissue specific manner, as a key step of cancer progression and pre-metastatic niche formation. However, this specificity might lead to new opportunities in cancer treatment by using EVs as devices for drug delivery. For future applications of EVs in cancer, improved protocols and methods for EVs isolation and visualization are required. Our group has put efforts on developing a protocol able to track the EVs for in vivo intern…
Intracellular Na+ concentration influences short-term plasticity of glutamate transporter-mediated currents in neocortical astrocytes.
2012
Fast synaptic transmission requires a rapid clearance of the released neurotransmitter from the extracellular space. Glial glutamate transporters (excitatory amino acid transporters, EAATs) strongly contribute to glutamate removal. In this work, we investigated the paired-pulse plasticity of synaptically activated, glutamate transporter-mediated currents (STCs) in cortical layer 2/3 astrocytes. STCs were elicited by local electrical stimulation in layer 4 in the presence of ionotropic glutamate (AMPA and NMDA), GABAA, and GABAB receptor antagonists. In experiments with low [Na+]i (5 mM) intrapipette solution, STCs elicited by paired-pulse stimulation demonstrated paired-pulse facilitation (…
Space charge effect on competitive ion transport through ion-exchange membranes
2002
A mathematical model of the competitive electro-transport of two counter-ions through an ion exchange membrane based on the Nernst-Planck and Poisson equations is developed. A three-layer system is considered: the membrane and two adjacent diffusion layers. Concentration profiles in the three layers, effective transport numbers as functions of the current and current-voltage characteristics are calculated. Deviation from the local electroneutrality in space charge region near the depleted solution/membrane interface is taken into account. It is shown that the space charge region grows with the voltage applied. However the fluxes of the competitive counter-ions at over-limiting currents are …
Glial ion transport and volume control.
1991
K(+)-induced glial swelling results from an intricate interaction of transport and diffusion processes and metabolic stimulation, with many open questions remaining. Our concept of the major mechanisms involved can be summarized as follows: high extracellular K+ causes a burst-like stimulation of Na+/K+ ATPase and, hence, increases the metabolic demands. Lactate is produced; the cell is slightly acidified. To maintain a normal intracellular pH, the Na+/K+ antiporter extrudes protons and supplies Na+ for further Na+/K+ exchange. In addition, K+ ions enter the cell via membrane channels or furosemide-inhibitable transport. K+, Cl-, and lactate- ions accumulate as the osmotic basis for cell sw…
Malic Enzyme and Malolactic Enzyme Pathways Are Functionally Linked but Independently Regulated in Lactobacillus casei BL23
2013
ABSTRACT Lactobacillus casei is the only lactic acid bacterium in which two pathways for l -malate degradation have been described: the malolactic enzyme (MLE) and the malic enzyme (ME) pathways. Whereas the ME pathway enables L. casei to grow on l -malate, MLE does not support growth. The mle gene cluster consists of three genes encoding MLE ( mleS ), the putative l -malate transporter MleT, and the putative regulator MleR. The mae gene cluster consists of four genes encoding ME ( maeE ), the putative transporter MaeP, and the two-component system MaeKR. Since both pathways compete for the same substrate, we sought to determine whether they are coordinately regulated and their role in l -m…
Human equilibrative nucleoside transporter 1 as a predictor of efficacy to gemcitabine in angiosarcoma and leiomyosarcoma.
2016
11062Background: Human equilibrative nucleoside transporter 1 (hENT1) is the major gemcitabine transporter into cells. Gemcitabine is an active drug in different sarcoma subtypes including leiomyos...
Neural and genetic correlates of antidepressant response to sleep deprivation - A functional magnetic resonance imaging study of moral valence decisi…
2007
Context: Total sleep deprivation combined with light therapy causes rapid amelioration of bipolar depression. A polymorphism in the promoter for the serotonin transporter influences both antidepressant response and the structure and function of specific brain areas. Objective: To determine whether antidepressant therapy or the genotype of the serotonin transporter influence the pattern of neural response to a task targeting the depressive biases in information processing (moral valence decision). Design: Before-and-after trial studying the biologic correlates of response to treatment. Setting: University hospital. Patients: Twenty inpatients with bipolar depression. Intervention: Repeated t…