[The effect of an original analog of the C-terminal fragment of vasopressin on the behavior of white rats].

The influence was studied of a new analog of C-terminal fragment of argininvasopressin Ac-D-MPRG on locomotor and exploratory activity of rats. The peptide injected intranasally in the doses of 0.001, 0.01, 0.1, 1, and 10 mcg/kg one hour prior to testing did not affect the horizontal motor activity of the animals in the "open field" (with red light and white noise) and "Opto-Varimex" tests. It increased the vertical motor activity and decreased grooming in the "open field" and "hole board" tests. The results obtained demonstrate that the analog of AVP (6-9) fragment (with Cys6 changed for D-Met), as well as AVP, increases the exploratory activity. However, in contrast to the whole precursor molecule, the peptide does not change the level of nonspecific motor activity.