[A comparative study on the effects of amiridin on learning and memory of old rats during passive avoidance test]. / Sravnitel'noe izuchenie vliianiia amiridina na obuchenie i pamiat' starykh krys v teste uslovnoi reaktsii passivnogo izbeganiia.

18-month rats showed much less learning ability in comparison with that of 3-month rats. 20-days treatment of old rats with amiridin, tacrine, and piracetam improved latency in passive avoidance test to the level of 3-month rats. The activity of acetylcholine esterase (AChE) from homogenates of old rat cortex was reduced as compared with that of young rats. After treatment with amiridin the activity of the enzyme remained unchanged, tacrine stimulate the decrease of activity of AChE while piracetam increased activity of AChE to the level of 3-month rats. The aging of rats is followed by the reduction of unsaturated fatty acids, the increase of cholesterol content and the increase of microviscosity of membranes of brain synaptosomes. Multiple treatment with amiridin, piracetam and tacrine normalized these indices.