Regulation of cytochrome oxidase activity in the rat forebrain throughout adulthood

• Published in: Neurobiology of aging Vol. 26; no. 7; pp. 1035 - 1050
• Main Authors: Riddle, D.R., Forbes, M.E.
• Format: Journal Article
• Language: English
• Published: London Elsevier Inc 01.07.2005; Elsevier Science
• Subjects: Age Factors; Aging; Animals; Animals, Newborn; Biochemistry and metabolism; Biological and medical sciences; Central nervous system; Cerebral blood flow; Cerebral cortex; Diagnostic Imaging - methods; Electron Transport Complex IV - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; Heart - growth & development; Heart - physiology; Hippocampus; Histocytochemistry - methods; Male; Oxidative metabolism; Prosencephalon - anatomy & histology; Prosencephalon - enzymology; Prosencephalon - growth & development; Rats; Rats, Inbred BN; Spectrophotometry - methods; Staining and Labeling - methods; Statistics as Topic; Vertebrates: nervous system and sense organs; Aging; Cerebral cortex; Oxidative metabolism; Cerebral blood flow; Hippocampus; Regional blood flow; Senescence; Rat; Enzyme; Rodentia; Central nervous system; Cytochrome-c oxidase; Metabolism; Encephalon; Vertebrata; Mammalia; Enzymatic activity; Animal; Hemodynamics; Oxidoreductases
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2004.09.010

Measures of metabolic activity can provide useful indices of the effects of aging on neural function, since sustained changes in neural activity alter metabolic demand and the activity of metabolic enzymes. Previous reports of effects of aging on key enzymes for oxidative metabolism are mixed, however, with some reports that activity declines in the aging brain and others that activity remains stable or increases. We used high-resolution, quantitative histochemistry to test whether cytochrome oxidase (CO) activity changes in the forebrain during adulthood and senescence, measuring activity in each layer of the hippocampus and several cerebral cortical areas. In most forebrain regions, average cytochrome oxidase activity was slightly higher in middle-aged than in young adult rats but did not differ between middle-aged and old rats. Thus, there was no significant change in cytochrome oxidase activity with senescence. Additional analyses indicated that cytochrome oxidase activity is regulated regionally in the brain, as well as focally, and that differences in regional regulation may contribute to variation in CO activity among individuals, which was greater in young and old rats than in middle-aged animals.