Patterns of lipid changes in membranes of the aged brain.

The lipid composition of cell plasma membranes reflects a steady-state between accumulation of serum lipids, predominantly cholesterol, and intracellular lipid synthesis and degradation. In the aging tissue this subtle balance is impaired with a net accumulation of cholesterol and other rigidifying lipids such as sphingomyelin in the membrane. As a consequence, most membrane processes, including ion transports in neuronal tissues, are slowed down. In principle, it is possible to rectify such adversative processes in vivo by increasing the level of specific phospholipids and glycerides in the serum.