Early postnatal treatment with peptide preparations influences spatial navigation of young and adult rats

The brain derived peptidergic drug Cerebrolysin has been found to support t he survival of neurons in vitro and in vivo. Positive effects on learning a nd memory have been demonstrated in various animal models and also in clini cal trials. In the present study the effects of early postnatal administrat ion of Cerebrolysin (Cere, 10 mg/ml peptides) or an enriched peptide fracti on of Cere (E021, 80.6 mg/ml peptides) were investigated in young, young ad ult, and old adult rats. Rat pups received the drugs or saline for control on postnatal days 1-7. The animals were tested in the Morris water maze (MW M) either in the 5th week, in the 3rd or the 16th month of life for 6 conse cutive days (test days 1-6), eight trials per day. In order to prevent the chance finding of the hidden platform, the rigid underwater platform was re placed by a collapsible island, resting at the bottom of the pool. The plat form was raised when the animal stayed in the target area for 2 s. In the y oung and young adult rats both Cere and E021 treated rats showed shorter es cape latencies than saline treated controls on all 6 test days. No signific ant differences in the swimming speed were evaluated for the young rats, al though in 3-month-old drug-tested animals a moderate increase of the swimmi ng speed was investigated. For 16-month-old animals no significant differen ces in either escape latencies or swimming speed was found. Summarizing, ea rly postnatal application of Cere or E021 improved the spatial learning and memory of young rats and led to long-lasting behavioural effects at least up to 3 months after treatment. (C) 1999 Elsevier Science B.V. All rights r eserved.