Glutamate Transport by Rcho-1 Cells Derived From Rat Placenta

Novak, Donald A.; Matthews, J. C.

doi:10.1203/01.pdr.0000061542.06874.2a

Cited by 6 publications

(2 citation statements)

References 41 publications

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“…Uridine uptake velocity (pmol·mg –1 protein·4 min –1 ) was determined using the 24-well cluster tray method and representative liquid scintillation counting , of [5- 3 H]-uridine ([ 3 H]-uridine, 5 μCi/mL uptake medium). Briefly, immediately before transport, cells were incubated for 15 min in an atmosphere of 95% air/5% CO 2 at 37 °C in 2 mL/well of depletion medium (ChKRP (pH 7.4); 119 mM choline Cl, 5.9 mM KCl, 1.2 mM MgSO 4 ·7H 2 O, 1.2 mM KHCO 3 , 5.6 mM glucose, 0.5 mM CaCl 2 ·2H 2 O, 25 mM choline HCO 3 ) to normalize intracellular amino acid and peptide pools.…”

Section: Methodsmentioning

confidence: 99%

Ergopeptines Bromocriptine and Ergovaline and the Dopamine Type-2 Receptor Inhibitor Domperidone Inhibit Bovine Equilibrative Nucleoside Transporter 1-like Activity

Miles

Xue

Strickland

et al. 2011

J. Agric. Food Chem.

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Neotyphodium coenophialum-infected tall fescue contains ergopeptines. Except for interactions with biogenic amine receptors (e.g., dopamine type-2 receptor, D2R), little is known about how ergopeptines affect animal metabolism. The effect of ergopeptines on bovine nucleoside transporters (NT) was evaluated using Madin-Darby bovine kidney (MDBK) cells. Equilibrative NT1 (ENT1)-like activity accounted for 94% of total NT activity. Inhibitory competition (IC(50)) experiments found that this activity was inhibited by both bromocriptine (a synthetic model ergopeptine and D2R agonist) and ergovaline (a predominant ergopeptine of tall fescue). Kinetic inhibition analysis indicated that bromocriptine inhibited ENT1-like activity through a competitive and noncompetitive mechanism. Domperidone (a D2R antagonist) inhibited ENT1 activity more in the presence than in the absence of bromocriptine and displayed an IC(50) value lower than that of bromocriptine or ergovaline, suggesting that inhibition was not through D2R-mediated events. These novel mechanistic findings imply that cattle consuming endophyte-infected tall fescue have reduced ENT1 activity and, thus, impaired nucleoside metabolism.

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Section: Methodsmentioning

confidence: 99%

Ergopeptines Bromocriptine and Ergovaline and the Dopamine Type-2 Receptor Inhibitor Domperidone Inhibit Bovine Equilibrative Nucleoside Transporter 1-like Activity

Miles

Xue

Strickland

et al. 2011

J. Agric. Food Chem.

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“…The transporters for placental taurine uptake show a substrate-specific adaptive response involving both transcriptional and post-transcriptional events in taurinedeprived JAR cells (Jayanthi et al 1995). More recently, Novak & Matthews (2003) identified that the system X 2 AG proteins, EAAC1, GLAST1 and GLT1, were involved in increased glutamate uptake into rat choriocarcinoma cells (Rcho-1) when cells are exposed to amino acid deprivation. However, there are no studies that have examined the effect of nutrient deprivation on flux across the whole cell layer, as opposed simply to uptake at the microvillar surface.…”

Section: Introductionmentioning

confidence: 99%

Expression and adaptive regulation of amino acid transport system A in a placental cell line under amino acid restriction

Jones¹,

Ashworth²,

Page³

et al. 2006

Reproduction

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Trans-placental transport of amino acids is vital for the developing fetus. Using the BeWo cell line as a placental model, we investigated the effect of restricting amino acid availability on amino acid transport system type A. BeWo cells were cultured either in amino acid-depleted (without non-essential amino acids) or control media for 1, 3, 5 or 6 h. System A function was analysed using a(methyl-amino)isobutyric acid (MeAIB) transcellular transport studies. Transporter (sodium coupled neutral amino acid transporter (SNAT1/2)) expression was analysed at mRNA and protein level by Northern and Western blotting respectively. Localisation was carried out using immunocytochemistry. MeAIB transcellular transport was significantly (P < 0.05) increased by incubation of the cells in amino acid-depleted medium for 1 h, and longer incubation times caused further increases in the rate of transfer. However, the initial response was not accompanied by an increase in SNAT2 mRNA; this occurred only after 3 h and further increased for the rest of the 6-h incubation. Similarly, it took several hours for a significant increase in SNAT2 protein expression. In contrast, relocalisation of existing SNAT2 transporters occurred within 30 min of amino acid restriction and continued throughout the 6-h incubation. When the cells were incubated in medium with even lower amino acid levels (without non-essential plus 0.5 3 essential amino acids), SNAT2 mRNA levels showed further significant (P < 0.0001) up-regulation. However, incubation of cells in depleted medium for 6 h caused a significant (P 5 0.014) decrease in the expression of SNAT1 mRNA. System L type amino acid transporter 2 (LAT2) expression was not changed by amino acid restriction, indicating that the responses seen in the system A transporters were not a general cell response. These data have shown that placental cells adapt in vitro to nutritional stress and have identified the physiological, biochemical and genomic mechanisms involved. Reproduction (2006) 131 951-960

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