[An experimental study of anti-amnestic activity of piracetam in orchidectomized rats].

The decrease of learning ability by 50% as assessed by passive avoidance test and the increase 28% of microviscosity of synaptosomal membranes from brain cortex were observed in rats in a month after orchidectomy as compared with that of intact or sham--operated animals. The treatment of orchidectomized rats with piracetam either by single application or in the course of 10 days applications in the daily dose of 250 mg/kg intraperitoneally failed to improve learning ability of animals in passive avoidance test and to produce a normalizing effect on the structure of membrane lipid matrix. The testosterone content in blood of orchidectomized rats was 10 times lower as compared with control and was not affected by treatment with piracetam.

[Study of anti-amnesic activity of amiridin in a model of amnesic syndrome].

The model of amnestic syndrome obtained by treatment with scopolamine during 20 days in rats was used to study anti-amnesic activity of amiridin in comparison with that of tacrine, physostigmine and piracetam. Multiple injection of Sc resulted in significant deterioration of rats, performance in passive avoidance test. Behavioral disorders were accompanied by such changes in lipid composition of brain synaptosomes which indicated a decreased membrane fluidity.

[Experimental study of the effects of amiridin and tacrine on learning and memory].

The authors studied the influence of amiridin and tacrine on learning and memory in mice and rat by passive avoidance conditioning test at norm and under scopolamine induced amnesia as well as of their effect on acetylcholine esterase (AChE) activity in brain cortex homogenates. Amiridin in doses 0.1 and 0.