| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Physiology and Biophysics, Finch University of Health Science/The Chicago Medical School, North Chicago, Illinois 60064-3095; and 2 Departamento de Bioquímica y Biología Molecular, Facultades de Medicina y Farmacia, Universitat de Valencia, Valencia 46010, Spain
Glutamine and glutamate transport activities were measured in isolated luminal and abluminal plasma membrane vesicles derived from bovine brain endothelial cells. Facilitative systems for glutamine and glutamate were almost exclusively located in luminal-enriched membranes. The facilitative glutamine carrier was neither sensitive to 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid inhibition nor did it participate in accelerated amino acid exchange; it therefore appeared to be distinct from the neutral amino acid transport system L1. Two Na-dependent glutamine transporters were found in abluminal-enriched membranes: systems A and N. System N accounted for ~80% of Na-dependent glutamine transport at 100 µM. Abluminal-enriched membranes showed Na-dependent glutamate transport activity. 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 for glutamine and glutamate at the luminal membrane may provide a mechanism for removing nitrogen and nitrogen-rich amino acids from brain.
brain microvessels; acidic amino acids; neutral amino acids; nitrogen balance
This article has been cited by other articles:
|
|
 |
|
  R. L. O'Kane, J. R. Vina, I. Simpson, R. Zaragoza, A. Mokashi, and R. A. Hawkins Cationic amino acid transport across the blood-brain barrier is mediated exclusively by system y+ Am J Physiol Endocrinol Metab, August 1, 2006; 291(2): E412 - E419. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. O'Kane, J. R. Vina, I. Simpson, and R. A. Hawkins Na+-dependent neutral amino acid transporters A, ASC, and N of the blood-brain barrier: mechanisms for neutral amino acid removal Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E622 - E629. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. O'Kane and R. A. Hawkins Na+-dependent transport of large neutral amino acids occurs at the abluminal membrane of the blood-brain barrier Am J Physiol Endocrinol Metab, December 1, 2003; 285(6): E1167 - E1173. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. E. Mann, D. L. Yudilevich, and L. Sobrevia Regulation of Amino Acid and Glucose Transporters in Endothelial and Smooth Muscle Cells Physiol Rev, January 1, 2003; 83(1): 183 - 252. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. R. Young and A. M. Ajami Glutamine: The Emperor or His Clothes? J. Nutr., September 1, 2001; 131(9): 2449S - 2459. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. R. Young and A. M. Ajami Glutamate: An Amino Acid of Particular Distinction J. Nutr., April 1, 2000; 130(4): 892 - 892. [Abstract] [Full Text]
|
|
|
|
|
|
Q. R. Smith Transport of Glutamate and Other Amino Acids at the Blood-Brain Barrier J. Nutr., April 1, 2000; 130(4): 1016 - 1016. [Abstract] [Full Text]
|
|
|
|
 |
|
 R. L. O'Kane, I. Martinez-Lopez, M. R. DeJoseph, J. R. Vina, and R. A. Hawkins Na+-dependent Glutamate Transporters (EAAT1, EAAT2, and EAAT3) of the Blood-Brain Barrier. A MECHANISM FOR GLUTAMATE REMOVAL J. Biol. Chem., November 5, 1999; 274(45): 31891 - 31895. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
