EFFECTS OF PIRACETAM ON MEMBRANE FLUIDITY IN THE AGED MOUSE, RAT, ANDHUMAN BRAIN

In vitro preincubation of brain membranes of aged mice with piracetam (0.1-1.0 mmol/L) enhanced membrane fluidity, as indicated by decreased anisotropy of the membrane-bound fluorescence probe 1,6-diphenyl-1,3, 5-hexatriene (DPH). Piracetam had similar in vitro effects on brain me mbranes of aged rats and humans, but it did not alter brain membrane f luidity in young mice. Chronic treatment of young and aged rats with p iracetam (300 mg/kg once daily) significantly increased membrane fluid ity in some brain regions of the aged animals, but had no measurable e ffect on membrane fluidify in the young rats. The same treatment signi ficantly improved active avoidance learning in the aged rats only. It is suggested that some of the pharmacological properties of piracetam can be explained by its effects on membrane fluidity. Copyright (C) 19 96 Elsevier Science Inc.