Animal model of anxiety: effect of chronic diazepam treatment in the genetically hypertensive rats of Koletsky type and in the rats of Wistar strain.

Experiments were performed in the adult normotensive rats of Wistar strain in the genetically hypertensive rats of Koltsky type. Diazepam at the dose of 1 mg/kg was applied for five days. The last two days of diazepam treatment the behavior of the animals was traced in holeboard and in the elevated plus-maze. In the control animals the genetically hypertensive rats of both sexes show elevated locomotor-exploratory activity in holeboard in both sessions, genetically hypertensive females show highest degree of directed exploration in holeboard when compared with the other groups of rats; in the elevated plus-maze the normotensive rats of both sexes show lower aversion towards open space and height in elevated plus-maze relative to genetically hypertensive rats. Diazepam only in the genetically hypertensive females increases in the second session locomotor-exploratory activity and reduced the inter-session habituation of the mentioned activity. Directed exploratory activity in holeboard was by diazepam treatment elevated predominantly in the genetically hypertensive rats. In the genetically hypertensive females diazepam caused inter-session sensitization in directed exploration. Considering the number of entries in centre and in open arms of the elevated plus-maze, diazepam in both strains irrespective of sex and session caused increase. Taking into account time spent in centre and in open arms of the elevated plus-maze, the strain dependent effect of diazepam is apparent, i.e., statistical significance of its "anxiolytic" effect was attained only in the genetically hypertensive rats.