Journal of Histochemistry and Cytochemistry Priciples for Free Access to Science
  Search:   
    >> Advanced Search

Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bixel, M. G.
Right arrow Articles by Hamprecht, B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bixel, M. G.
Right arrow Articles by Hamprecht, B.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Journal of Histochemistry and Cytochemistry, Vol. 49, 407-418, March 2001, Copyright © 2001, The Histochemical Society, Inc.

ARTICLE

Distribution of Key Enzymes of Branched-chain Amino Acid Metabolism in Glial and Neuronal Cells in Culture

M. Gabriele Bixela, Yoshiharu Shimomurab, Susan M. Hutsonc, and Bernd Hamprechta
a Physiologisch-chemisches Institut der Universität, Tübingen, Germany
b Nagoya Institute of Technology, Nagoya, Japan
c Department of Biochemistry, Wake Forest University School of Medicine, Winston–Salem, North Carolina

Correspondence to: Susan M. Hutson, Wake Forest U. School of Medicine, Department of Biochemistry, Winston-Salem, NC 27157. E-mail: shutson@wfubmc.edu

Transamination of branched-chain amino acids (BCAAs) catalyzed by the branched chain aminotransferase isoenzymes (BCATs) is believed to play an important role in nitrogen shuttling and excitatory neurotransmitter glutamate metabolism in brain. Recently, we have shown that the mitochondrial isoenzyme (BCATm) is the predominant form found in cultured astrocytes. In this study we used immunocytochemistry to examine the distribution of BCAT isoenzymes in cultured rat neurons and microglial cells. The cytoplasm of neurons displayed intense staining for the cytosolic isoenzyme (BCATc), whereas BCATm staining was not detectable in neurons. In contrast, microglial cells expressed BCATm in high concentration. BCATc appeared to be absent in this cell type. The second and committed step in the BCAA catabolic pathway is oxidative decarboxylation of the {alpha}-keto acid products of BCAT catalyzed by the branched-chain {alpha}-keto acid dehydrogenase (BCKD) enzyme complex. Because the presence of BCKD should provide an index of the ability of a cell to oxidize BCAA, we have also immunocytochemically localized BCKD in neuron and glial cell cultures from rat brain. Our results suggest ubiquitous expression of this BCKD enzyme complex in cultured brain cells. BCKD immunoreactivity was detected in neurons and in astroglial and microglial cells. Therefore, the expression of BCAT isoenzymes shows cell-specific localization, which is consistent with the operation of an intercellular nitrogen shuttle between neurons and astroglia. On the other hand, the ubiquitous expression of BCKD suggests that BCAA oxidation can probably take place in all types of brain cells and is most likely regulated by the activity state of BCKD rather than by its cell-specific localization. (J Histochem Cytochem 49:407–418, 2001)

Key Words: brain cells, branched-chain amino acid, cell culture, energy metabolism, immunocytochemistry, nitrogen metabolism


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 J. Nutr.Home page
S. M. Hutson, A. J. Sweatt, and K. F. LaNoue
Branched-Chain Amino Acid Metabolism: Implications for Establishing Safe Intakes
J. Nutr., June 1, 2005; 135(6): 1557S - 1564S.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Endocrinol. Metab.Home page
A. J. Sweatt, M. Wood, A. Suryawan, R. Wallin, M. C. Willingham, and S. M. Hutson
Branched-chain amino acid catabolism: unique segregation of pathway enzymes in organ systems and peripheral nerves
Am J Physiol Endocrinol Metab, January 1, 2004; 286(1): E64 - E76.
[Abstract] [Full Text]



Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact
The Journal of Histochemistry & Cytochemistry is owned, published, and licensed by The Histochemical Society © 2001