A.S. Belyakova, O.G. Voskresenskaya, A.A. Kamensky, E.B. Evstigneeva, V.P. Golubovich

The influence of synthetic structural analogue of arginine-vasopressin (AVP) Ac-D-SPRG on orientation and exploratory activity, level of anxiety and depression state of white rats was studied. The Ac-D-SPRG was injected nasally in doses of 0,01; 0,1; 1,0 and 10,0 mkg/kg in volume of 1 mkl per 10 g of body weight 5 min before the testing. The behavioral reactions of animals were studied in next test: the orienting and exploratory activity in «open field» (in nonstressogenic and stressogenic conditions) and in «hole board», the anxiety level of rats in «elevated plus maze» and «dark-light chamber», the state of depression (the structure and parameters of swimming) in «forced swimming test». The results of conducted experiments demonstrated that all doses of Ac-D-SPRG caused depression of orientation and exploration activity which was mostly expressed in test «hole board» test, i.e. Ac-D-SPRG injection led to significant decrease of vertical exploratory activity and number of explored holes. The analogue Ac-D-SPRG caused slight increase of anxiety level in animals in case of single intranasal injection. The decreased time of presence at light evidences for higher anxiety level together with decrease of vertical activity and number of outcomes to open arms of «elevated plus maze». However, Ac-D-SPRG had the expressed antidepressant influence resulting in increase of summary time of both active and passive swimming, decrease of summary immobilization time and prolonged periods of active swimming. This tetrapeptide may be recommended for further studies as potential drug.