Melatonin preserves longevity protein (sirtuin 1) expression in the hippocampus of total sleep-deprived rats

• Published in: Journal of pineal research Vol. 47; no. 3; pp. 211 - 220
• Main Authors: Chang, Hung-Ming, Wu, Un-In, Lan, Chyn-Tair
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.10.2009; Blackwell
• Subjects: Adrenocorticotropic Hormone - blood; Animals; Biological and medical sciences; Body Weight - drug effects; Central Nervous System Depressants - pharmacology; Corticosterone - blood; cytochrome oxidase; Electron Transport Complex IV - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; hippocampus; Hippocampus - drug effects; Hippocampus - metabolism; Immunohistochemistry; Male; Maze Learning - drug effects; melatonin; Melatonin - pharmacology; neuronal plasticity; quantitative image analysis; Rats; Rats, Wistar; sirtuin 1; Sirtuin 1 - metabolism; sleep deprivation; Sleep Deprivation - metabolism; Sleep Deprivation - physiopathology; Sleep. Vigilance; Vertebrates: endocrinology; Vertebrates: nervous system and sense organs; Cytochrome; sirtuin 1; Melatonin; Rat; Rodentia; Central nervous system; Longevity; Gene expression; Encephalon; quantitative image analysis; neuronal plasticity; Vertebrata; Image analysis; sleep deprivation; Mammalia; Sleep; cytochrome oxidase; Animal; Plasticity; Sleep wake cycle; Hippocampus; Pineal hormone; Quantitative analysis
• ISSN: 0742-3098; 1600-079X
• DOI: 10.1111/j.1600-079X.2009.00704.x

:  Sleep disorders cause cognitive dysfunction in which impaired neuronal plasticity in the hippocampus may underline the molecular mechanisms of this deficiency. As sirtuin 1 (SIRT1) plays an important role in maintaining metabolic homeostasis and neuronal plasticity, this study is aimed to determine whether melatonin exerts beneficial effects on preserving SIRT1 activation following total sleep deprivation (TSD). TSD was performed by disc on water method for five consecutive days. During this period, animals daily received melatonin at doses of 5, 25, 50 or 100 mg/kg. The cytochrome oxidase (COX) histochemistry, SIRT1 immunohistochemistry together with Morris water maze learning test were performed to examine the metabolic, neurochemical, as well as the behavioral changes in neuronal plasticity, respectively. The results indicate that in normal rats, numerous COX and SIRT1 positive‐labeled neurons with strong staining intensities were found in hippocampal pyramidal and granular cell layers. Following TSD, both COX and SIRT1 reactivities were drastically decreased as revealed by reduced staining pattern and labeling frequency. Behavioral data corresponded well with morphological findings in which spatial memory test in water maze was significantly impaired after TSD. However, in rats receiving different doses of melatonin, both COX and SIRT1 expressions were successfully preserved. Considerably better performance on behavioral testing further strengthened the beneficial effects of melatonin. These findings suggest that melatonin may serve as a novel therapeutic strategy directed for preventing the memory deficits resulting from TSD, possibly by effectively preserving the metabolic function and neuronal plasticity engaged in maintaining cognitive activity.