Memory-related changes in L-citrulline and agmatine in the rat brain

✍ Scribed by Ping Liu; Yu Jing; Nicola D. Collie; Sree Chary; Hu Zhang

• Book ID: 102243662
• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 134 KB
• Volume: 19
• Category: Article
• ISSN: 1050-9631
• DOI: 10.1002/hipo.20561

✦ Synopsis

Abstract

L‐citrulline, L‐ornithine, and agmatine are the metabolites of L‐arginine by nitric oxide synthase (NOS), arginase, and arginine decarboxylase (ADC), respectively. In contrast to the NOS and arginase pathways, the role of the ADC‐agmatine pathway in learning and memory has only been paid attention lately. Recent evidence suggests a potential involvement of agmatine in learning and memory processing. The present study further addressed this issue by comparing the levels of agmatine, as well as L‐arginine, L‐citrulline, and L‐ornithine, in the hippocampus, parahippocampal region, prefrontal cortex, vestibular nucleus, and cerebellum in rats that were trained in the delayed nonmatch to position task in the T‐maze with their yoked controls. There were significantly increased agmatine levels in the prefrontal, entorhinal, and perirhinal cortices and increased L‐citrulline concentrations in the dentate gyrus (DG) and prefrontal cortex in the T‐maze training group relative to the control one. L‐arginine and L‐ornithine levels were not significantly different between groups in the brain regions examined. These results demonstrate T‐maze training‐induced region‐specific increases in L‐citrulline and agmatine. Significant positive correlations between prefrontal and perirhinal agmatine levels and animals' performance in the T‐maze further suggest the direct involvement of agmatine in learning and memory processing. © 2009 Wiley‐Liss, Inc.