Distribution of D-3-aminoisobutyrate-pyruvate aminotransferase in the rat brain
1 Department of Neuropsychiatry, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
2 Department of Anatomy and Embryology, Neuroscience, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
3 Department of Neuropsychiatry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, 1-1-1, Honjo, Chuou-ku, Kumamoto, Kumamoto 860-8556, Japan
BMC Neuroscience 2014, 15:53 doi:10.1186/1471-2202-15-53Published: 27 April 2014
D-3-aminoisobutyrate, an intermediary product of thymine, is converted to 2-methyl-3-oxopropanoate using pyruvate as an amino acceptor by D-3-aminoisobutyrate-pyruvate aminotransferase (D-AIB AT; EC 220.127.116.11). A large amount of D-AIB AT is distributed in the kidney and liver; however, small amounts are found in the brain. Recently, D-AIB AT was reported to metabolize asymmetric dimethylarginine (ADMA) in vivo and was suggested to be an important enzyme for nitric oxide metabolism because ADMA is a competitive inhibitor for nitric oxide synthase. In this study, we examined the distribution of D-AIB AT in the rat brain further to understand its role. We measured D-AIB AT mRNA and protein expression using quantitative RT-PCR and Western blotting, and monitored its distribution using immunohistochemical staining.
D-AIB AT was distributed throughout the brain, with high expression in the cortex and hippocampus. Immunohistochemical staining revealed that D-AIB AT was highly expressed in the retrosplenial cortex and in hippocampal neurons.
Our results suggest that D-AIB AT is distributed in the examined- just the regions and may play an important role there.