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Blood‐Brain Barrier Transport of 1‐Aminocyclohexanecarboxylic Acid, a Nonmetabolizable Amino Acid for In Vivo Studies of Brain Transport
Author(s) -
Aoyagi Masaki,
Agranoff Bernard W.,
Washburn Lee C.,
Smith Quentin R.
Publication year - 1988
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1988.tb10596.x
Subject(s) - amino acid , methionine , phenylalanine , tyrosine , in vivo , chemistry , isoleucine , biochemistry , blood–brain barrier , biophysics , stereochemistry , biology , leucine , central nervous system , endocrinology , microbiology and biotechnology
Regional transport of 1‐aminocyclohexanecarboxylic acid (ACHC), a nonmetabolizable amino acid, across the blood‐brain barrier was studied in pentobarbital‐anesthetized rats using an in situ brain perfusion technique. The concentration dependence of influx was best described by a model with a saturable and a nonsaturable component. Best‐fit values for the kinetic constants of the frontal cortex equaled 9.7 × 10‐ −4 μmol/s/g for V max , 0.054 μmol/ml for K m , and 1.0 × 10‐ −4 ml/s/g for K D in the absence of competing amino acids. Saturable influx could be reduced by >85% by either l‐phenylalanine or 2‐aminobicyclo[2.2.1]heptane‐2‐carboxylic acid, consistent with transport by the cerebrovascular neutral amino acid transport system. The transport K m for ACHC was one‐fifth that for the more commonly used homologue, I‐aminocyclopentanecarboxylic acid, and was similar to values for several natural amino acids, such as l‐methionine, l‐isoleucine, and l‐tyrosine. The results indicate that ACHC may be a useful probe for in vivo studies of amino acid transport into brain.