Na+-dependent transport of large neutral amino acids occurs at the abluminal membrane of the blood-brain barrier.

@article{OKane2003NadependentTO,
  title={Na+-dependent transport of large neutral amino acids occurs at the abluminal membrane of the blood-brain barrier.},
  author={Robyn L. O'Kane and Richard Albert Hawkins},
  journal={American journal of physiology. Endocrinology and metabolism},
  year={2003},
  volume={285 6},
  pages={
          E1167-73
        }
}
Several Na+-dependent carriers of amino acids exist on the abluminal membrane of the blood-brain barrier (BBB). These Na+-dependent carriers are in a position to transfer amino acids from the extracellular fluid of brain to the endothelial cells and thence to the circulation. To date, carriers have been found that may remove nonessential, nitrogen-rich, or acidic (excitatory) amino acids, all of which may be detrimental to brain function. We describe here Na+-dependent transport of large… 

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References

SHOWING 1-10 OF 54 REFERENCES

Neutral Amino Acid Transport Characterization of Isolated Luminal and Abluminal Membranes of the Blood-Brain Barrier (*)

The neutral amino acid carrier composition of luminal and abluminal membranes of the blood-brain barrier has been studied using isolated membrane vesicles andKinetic and inhibition experiments indicated that one of these activities was probably the main route for Na-dependent alanine transport under physiological conditions.

Neutral amino acid transport by the blood-brain barrier. Membrane vesicle studies.

Glutamine transport by the blood-brain barrier: a possible mechanism for nitrogen removal.

The presence of 1) Na-dependent carriers capable of pumping glutamine and glutamate from brain into endothelial cells, 2) glutaminase within endothelial Cells to hydrolyze glutamine to glutamate and ammonia, and 3) facilitative carriers at the luminal membrane may provide a mechanism for removing nitrogen and nitrogen-rich amino acids from brain.

Polarity of the blood-brain barrier: neutral amino acid transport into isolated brain capillaries.

It is concluded that Na+-dependent neutral amino acid transport is located on the brain side and the luminal plasma membrane and the antiluminal plasma membranes appear to be functionally distinct, which should permit brain capillary endothelial cells to actively regulate the internal milieu of the brain.

Selective expression of the large neutral amino acid transporter at the blood-brain barrier.

These studies show that the LAT1 transcript is selectively expressed at the BBB compared with other tissues, and the abundance of the LAT 1 mRNA at theBBB is manyfold higher than that of transcripts such as the 4F2hc antigen, actin, or the Glut1 glucose transporter.

The Complementary Membranes Forming the Blood‐Brain Barrier

It is now clear that the blood‐brain barrier participates in the active regulation of brain extracellular fluid, and that the diverse functions of each plasma membrane domain contributes to these regulatory functions.

Kinetics of Neutral Amino Acid Transport Across the Blood‐Brain Barrier

Predicted influx values from transport constants and average plasma concentrations agree well with values measured using plasma perfusate and suggest that affinity of a l‐α‐amino acid for the transport system is determined primarily by side‐chain hydrophobicity.

Na 1-dependent Glutamate Transporters ( EAAT 1 , EAAT 2 , and EAAT 3 ) of the Blood-Brain Barrier

To determine whether the above-mentioned transporters participate in glutamate transport of the blood-brain barrier, total RNA was extracted from bovine cerebral capillaries and cDNA for EAAT1, EAAT2, and EAAT3 was observed, indicating that mRNA was present.

Evidence for an Alanine, Serine, and Cysteine System of Transport in Isolated Brain Capillaries

The results indicate that the transport of MeAIB and 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH) was limited to the sodium-dependent system A (alanine) and the Sodium-independent system L (leucine), respectively.
...