[Psychostimulation of Wistar rats after intraperitoneal administration of high-molecular heparin]

The influence of repeated administration of heparin in learning was studied in Wistar rats (n = 20). High-molecular heparin (Serva, Germany, 10 kDa, activity of 180 IU/mg) was intraperitoneally injected daily in the dose of 64 IU/kg in a volume of 0.3 ml during 5 days prior to 4-link freechoice operant conditioning in a complex maze. As distinct from 40% of control rats, practically all heparin-treated rats were successful in conditioning. Parameters such as rate and efficiency of learning, behavior organization, habit stability, and extinction of errors were significantly better than in control animals. Anxiety was decreased, but sensitivity to external factors was increased in comparison with the control rats. The data obtained suggest that prior treatment with high-molecular heparin has a strong psychostimulant effect through activation of biogenic amines and formation of complexes with them.