[The effect of beta-casomorphin-7 on the level of food and defense motivations in different types of learning].

The effects of intraperitoneal administration of the heptapeptide beta-casomorphin-7 (beta-C-7) on learning were investigated in white rats using T-maze, active and passive avoidance tests. The substance injected in the dose of 5 mg/kg 5 min prior to training accelerated the acquisition of food-reinforced task increasing the number of correct trials in T-maze. The same injection in the dose of 1 mg/kg impaired the acquisition of avoidance tasks. The heptapeptide didn't influence food motivation and consolidation of memory trace. The data obtained support the idea that beta-C-7 attenuated manifestations of defensive motivation.