Differential expression of the cationic amino acid transporter 2(B) in theadult rat brain

L-Arginine is a substrate for the synthesis of proteins, nitric oxide (NO), creatine, urea, proline, glutamate, polyamines and agmatine. In the centra l nervous system (CNS), arginine is extracted from the blood and exchanged by cells through carriers called cationic amino acid transporters (CAT) and belonging to the so-called system y(+). In order to better understand the arginine transport in the CNS, we studied in detail the regional distributi on of the cells expressing the CAT2(B) transcript in the adult rat brain by non-radioisotopic in situ hybridization. We show that CAT2(B) is expressed in neurons and oligodendrocytes throughout the brain, but is not detected in astrocytes. The pattern of localization of CAT2(B) in the normal adult r at brain fits closely that of CRT1, a specific creatine transporter. Our st udy demonstrates that the in vivo expression of CAT2(B) differs from that r eported in vitro, implying that local cellular interactions should be taken into account in studies of gene regulation of the CAT2(B) gene. Our work s uggests that CAT2(B) may play a role in case of increased NO production as well as arginine or creatine deficiency in the brain. (C) 2001 Elsevier Sci ence B.V. All rights reserved.