Effects of aging on the relation of adenyl purine release with plasma membrane fluidity of arterial endothelial cells.
Age-related changes in adenyl purine release from rat arteries and endothelial cell (EC) plasma membrane (PM) fluidity were studied. High performance liquid chromatography-fluorescence revealed that aging significantly decreased the release of adenyl purines. Pyrene-excimer spectroscopy disclosed that EC PM fluidity of aged rats decreased more significantly than that of young rats. An increase in cholesterol content and a decrease in the unsaturation index (USI) of fatty acids in cholesterol-enriched ECs reduced PM fluidity and 5'-nucleotidase (5'-ND) activity (measured by coupled assay of adenosine deaminase and glutamate dehydrogenase). Moreover, a decrease in cholesterol content and an increase in the USI of fatty acyl chains of the PM in docosahexaenoic acid-enriched ECs concurrently increased enzyme activity and extracellular adenosine. Therefore, decreases in PM fluidity, observed with age-dependent increased cholesterol and decreased USI, induce a decrease in 5'-ND activity, decrease extracellular adenosine levels, and might relate to hypertension in aged rats.
Hashimoto
Michio
M
Department of Environmental Physiology, Shimane University, Faculty of Medicine, Izumo, Japan. michio1@med.shimane-u.ac.jp
Hossain
Shahdat
S
Tanabe
Yoko
Y
Shido
Osamu
O
D015720:5'-Nucleotidase / Q000378:metabolism; D000227:Adenine Nucleotides / Q000378:metabolism*; D000241:Adenosine / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D001158:Arteries / Q000166:cytology / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002784:Cholesterol / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D008560:Membrane Fluidity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D000227:Adenine Nucleotides; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D004281:Docosahexaenoic Acids; D002784:Cholesterol; D015720:5'-Nucleotidase; D000241:Adenosine