Cerebral microvessel phospholipase A2 activity in senescent mouse.
Phospholipase A2 activity was measured in cerebral microvessels isolated from 5 to 6 month (young adult) and 21 to 24 month (aged adult) old mice. Radiolabeled 1-stearoyl-2-[1-14C]arachidonyl choline phosphoglyceride was used as the enzyme substrate, and enzyme activity determined at pH 8 and pH 9. Activity in older animals was significantly less than in younger animals at both pH's. With choline phosphoglyceride as a substrate, phospholipase A2 activity was predominantly Ca(2+)-dependent, although a small, but measurable Ca(2+)-independent component was present. Negligible production of diacylglycerol indicated little or no phospholipase C activity. These findings indicate that activity of a phospholipase A2, which utilizes choline phosphoglyceride as a substrate, is affected by the aging process. Moreover, a change in PLA2 activity would result in altered metabolism of specific phosphoglycerides and turnover of fatty acids at the sn-2 position in cerebral microvessels.
Williams
W M
WM
Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892-0010.
Chang
M C
MC
Rapoport
S I
SI
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002560:Cerebrovascular Circulation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation / Q000201:enzymology* / Q000254:growth & development; D024510:Muscle Development; D009131:Muscle, Smooth, Vascular / Q000201:enzymology / Q000254:growth & development; D010713:Phosphatidylcholines / Q000378:metabolism; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2
D010713:Phosphatidylcholines; C043644:1-stearoyl-2-arachidonylphosphatidylcholine; D010741:Phospholipases A; D054467:Phospholipases A2