Uptake of [3H]l-serine in rat brain synaptosomal fractions

Takarada, Takeshi; Balcar, Vladimír J.; Baba, Katsuhiro; Takamoto, A. H. R.; Acosta, Gabriela Beatriz; Takano, Katsura; Yoneda, Yukio

doi:10.1016/s0006-8993(03)03024-5

Cited by 17 publications

(17 citation statements)

References 51 publications

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“…On the other hand, recent studies showed that LAT1 and LAT2 functioned also as transporters for serine (37,38). In some cell types, serine accumulation is predominantly mediated by LAT (39). Another study suggested that serine may inhibit LAT1 and LAT2 both in sodium-free and sodium-containing media (40).…”

Section: Discussionmentioning

confidence: 99%

L-Type Amino Acid Transporters LAT1 and LAT4 in Cancer: Uptake of 3-O-Methyl-6- 18F-Fluoro-L-Dopa in Human Adenocarcinoma and Squamous Cell Carcinoma In Vitro and In Vivo

Haase¹,

Bergmann²,

Fuechtner³

et al. 2007

Journal of Nuclear Medicine

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Expression of system L amino acid transporters (LAT) is strongly increased in many types of tumor cells. The purpose of this study was to demonstrate that 18 F-labeled amino acids, for example, 3-O-methyl-6-18 F-fluoro-L-dopa ( 18 F-OMFD), that accumulate in tumors via LAT represent an important class of imaging agents for visualization of tumors in vivo by PET. Methods: 18 F-OMFD uptake kinetics, transport inhibition, and system L messenger RNA expression were studied in vitro in human adenocarcinoma (HT-29), squamous cell carcinoma (FaDu), macrophages (THP-1), and primary aortic endothelial cells (HAEC) and in vivo in the corresponding mouse tumor xenograft models. Results: Uptake of 18 F-OMFD in all cell lines tested was mediated mainly by the sodium-independent high-capacity LAT. We found higher uptake in FaDu cells (V max , 10.6 6 1.1 nmol/min · mg of cell protein) and in the corresponding FaDu tumor xenografts than in the other cells and corresponding xenograft models studied. Quantitative messenger RNA analysis revealed that tumor cells and xenografts have a higher expression of LAT1 than do HAEC and THP-1 macrophages. However, only in the FaDu tumor model did an increased 18 F-OMFD uptake seem to be explained by increased LAT expression. Furthermore, we demonstrated a high expression of LAT4, a recently identified LAT. Conclusion: Our findings support the hypothesis that 18 F-OMFD is a tracer for visualization of tumor cells. 18 F-OMFD particularly seems to be a suitable tracer for diagnostic imaging of amino acid transport in poorly differentiated squamous cell head and neck carcinoma with increased LAT1 and LAT4 expression.

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Section: Discussionmentioning

confidence: 99%

L-Type Amino Acid Transporters LAT1 and LAT4 in Cancer: Uptake of 3-O-Methyl-6- 18F-Fluoro-L-Dopa in Human Adenocarcinoma and Squamous Cell Carcinoma In Vitro and In Vivo

Haase¹,

Bergmann²,

Fuechtner³

et al. 2007

Journal of Nuclear Medicine

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“…The pellets thus obtained (P2) were suspended in 0·32 M sucrose and centrifuged at 20 000 g for 20 min again. These washing procedures were repeated three times, and the final pellets were suspended in HEPES buffer (125 mM NaCl, 3·5 mM KCl, 1·5 mM CaCl 2 , 1·2 mM MgSO 4 , 1·25 mM KH 2 PO 4 , 25 mM NaHCO 3 , 10 mM HEPES and 10 mM -glucose (pH 7·4)) for use in the uptake experiments (Takarada et al 2003). Membrane suspensions were preincubated for 5 min at 2 C or 30 C, followed by incubation with 10 nM [ 3 H]-Glu for 1-60 min.…”

Section: [ 3 H]glu Uptake Assaymentioning

confidence: 99%

Possible expression of functional glutamate transporters in the rat testis

Takarada¹,

Hinoi²,

Balcar³

et al. 2004

Journal of Endocrinology

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Neither expression nor functionality is clear in peripheral tissues with the molecular machineries required for excitatory neurotransmitter signaling by -glutamate (Glu) in the central nervous system, while a recent study has shown that several Glu receptors are functionally expressed in the rat testis. This fact prompted us to explore the possible functional expression in the rat testis of the Glu transporters usually responsible for the regulation of extracellular Glu concentrations in the brain. RT-PCR revealed the expression, in the rat testis, of mRNA for five different subtypes of Glu transporters, in addition to that for particular subtypes of ionotropic and metabotropic Glu receptors. Glutamate transporter-1 (GLT-1) was different in the brain from that in the testis in terms of molecular sizes on Northern and Western blot analyses. In situ hybridization as well as immunohistochemical analysis showed localized expression of glutamate aspartate transporter at interstitial spaces and GLT-1 at elongated spermatids in the rat testis respectively. The expression of mRNA was localized for excitatory amino acid transporter-5 at the basal compartment of the seminiferous tubule in the rat testis. [ 3 H]Glu was accumulated in testicular crude mitochondrial fractions in a temperatureand sodium-dependent saturable manner with pharmacological profiles similar to those shown in brain crude mitochondrial fractions. These results suggested that particular subtypes of central Glu transporters for the regulation of extracellular Glu concentrations in the rat testis could be constitutively and functionally expressed.

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“…The pellet (P2=crude synaptosomal fraction) was suspended with a glass-PTFE homogenizer in fresh Krebs buffer and again centrifuged at 20,000 g for 20 min. This procedure was repeated three times; the resulting pellet was re-suspended and was used in uptake experiments within 5 hrs of preparation [33,36]. Time course experiments were performed to demonstrate that Glu uptake is linear until 5 min (data not shown).…”

Section: Tissue Samples Preparation and [ 3 H]l-glu Uptakementioning

confidence: 99%

Consequences of Postnatal Stress: Maternal Separation in Rats Induces Long-Lasting Changes on Glutamate Transporters

Odeon¹,

Salatino²,

Acosta

2015

Clin Exp Pharmacol

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Background: There is increasing evidence that environmental factors, particularly stressful events experienced early in life, increase the risk of developing a psychiatric illness and/or a behavioural disorder. The aim of this study was to evaluate the effects of acute and chronic maternal separation (AMS and CMS) plus cold stress on the expression patterns of Glutamate Transporters (TGlus) in the developing and young adult Central Nervous System (CNS). As regulation of Glutamate (Glu) extracellular levels is of key importance, sodium-dependent Glu uptake using synaptosome-enriched fractions isolated from Frontal Cortex (FC) and Hippocampus (Hic) was also studied.

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Uptake of [3H]l-serine in rat brain synaptosomal fractions

Cited by 17 publications

References 51 publications

L-Type Amino Acid Transporters LAT1 and LAT4 in Cancer: Uptake of 3-O-Methyl-6- 18F-Fluoro-L-Dopa in Human Adenocarcinoma and Squamous Cell Carcinoma In Vitro and In Vivo

L-Type Amino Acid Transporters LAT1 and LAT4 in Cancer: Uptake of 3-O-Methyl-6- 18F-Fluoro-L-Dopa in Human Adenocarcinoma and Squamous Cell Carcinoma In Vitro and In Vivo

Possible expression of functional glutamate transporters in the rat testis

Consequences of Postnatal Stress: Maternal Separation in Rats Induces Long-Lasting Changes on Glutamate Transporters

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