The effects of analogs of the C-terminal fragment of arginine-vasopressin on the dynamics of development of a conditioned active avoidance response in rats.

This paper reports studies of the effects of original analogs of the C-terminal fragment AVP(6-9), D-MPR and D-MPRG, on the development of a conditioned active avoidance response in rats; agents were given intranasally over a wide range of doses. The most effective does of D-MPR was 0.1 microgram/kg, and the most effective dose of D-MPRG was 0.01 microgram/kg. The tri- and tetrapeptide doses were 10 and 100 times smaller than the dose of arginine-vasopressin used in analogous experimental conditions. The tri- and tetrapeptide accelerated development of the active avoidance conditioned response, affecting both formation of the habit and consolidation of the memory trace. The actions of these peptides were mainly on perception processes, i.e., isolation of the concrete stimulus from the environment, and assessment and remembering of its biological significance.