Hippocampal nitric oxide synthase and arginase and age-associated behavioral deficits.
The present study investigated age-related changes in nitric oxide synthase (NOS) and arginase in the subregions of the hippocampus and their correlations with animals' performance in the open field, T-maze, and water maze tasks. Aged rats (24 months old) showed reduced exploratory activity and poorer spatial learning relative to the young adults (4 months old). Significant increases in total NOS activity were found in the aged dentate gyrus and a dramatic decrease in endothelial NOS expression was observed in the aged CA2/3. Activity or protein expression of inducible NOS was not detected in any subregion of the hippocampus. There were no age-related changes in total arginase activity or arginase I and arginase II protein expression. Correlation analysis revealed that animals' motor ability was associated with CA1 NOS and arginase, as well as hippocampal function. The present findings provide further support for the involvement of NOS/NO and arginase in the normal aging process. A strong positive correlation between CA1 eNOS protein expression and swimming speed in the water maze task may reflect a relationship between the local cerebral blood flow and neuronal activity.
Liu
Ping
P
Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago, Dunedin, New Zealand. ping.liu@stonebow.otago.ac.nz
Smith
Paul F
PF
Appleton
Ian
I
Darlington
Cynthia L
CL
Bilkey
David K
DK
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001119:Arginase / Q000378:metabolism*; D001522:Behavior, Animal / Q000502:physiology; D003072:Cognition Disorders / Q000378:metabolism*; D006624:Hippocampus / Q000201:enzymology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008568:Memory / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017207:Rats, Sprague-Dawley; D013028:Space Perception / Q000502:physiology
D009419:Nerve Tissue Proteins; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D001119:Arginase