title: Turnover of synaptic membranes: age-related changes and modulation by dietary restriction.
abstract: We examined age-related changes in the turnover rates of synaptic membrane components that might underlie the decrease in synaptic functions in senescence. Synaptic membrane constituents were labeled in vivo with deuterium and the disappearance of the deuterated molecules from synaptic membranes was measured by mass spectrometry. The turnover rates of phosphatidylcholine, phosphatidylethanolamine, cholesterol, and synaptophysin were all shown to slow down with aging. Dietary restriction, which is known to retard various aging processes, was found to decrease the turnover rates of membrane lipid species. Consequently, the fatty acid composition in phospholipids remained unchanged in the synaptic plasma membranes of food restricted mice. In contrast, the turnover rate of synaptophysin was accelerated under dietary restriction. This may mean that increased turnover enhances the removal of damaged proteins from membranes.
authors.affiliation: Neuronal Function Research Group, Division of Neuroscience, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan. andos@tmig.or.jp
authors.forename: Susumu
authors.initials: S
authors.lastname: Ando
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Toyoda nee Ono
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kon
authors.forename: Sei-Ichi
authors.initials: S
authors.lastname: Kawashima
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002784:Cholesterol / Q000378:metabolism; D003903:Deuterium; D005227:Fatty Acids / Q000378:metabolism; D005508:Food Deprivation / Q000502:physiology*; D008563:Membrane Lipids / Q000378:metabolism*; D051379:Mice; D019636:Neurodegenerative Diseases / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D013570:Synaptic Membranes / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D016708:Synaptophysin; D002784:Cholesterol; D003903:Deuterium