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

: The experiments were carried out in the younger adult (3 to 5 months of age) normotensive rats of Wistar strain and in the genetically hypertensive rats which were developed by Koletsky; the experiments were performed in both sexes. The behaviour of control and diazepam treated rats were traced in the holeboard and in the elevated plus-maze. In the control animals when compared to the normotensive rats of both sexes, the genetically hypertensive rats of both sexes show elevated aversion towards open space and hight (when the number of visits of centre and open arms is considered), and elevated total time of locomotor-exploratory activity; the hypertensive males show decrease and female increase in time spent and in number of head-dipping. Diazepam at both doses (0.5-1.0 mg/kg b. w.) alleviates aversion towards open space and hight in the elevated plus-maze only in the genetically hypertensive rats. Directed exploration (head-dipping) was increased in the genetically hypertensive rats of both sexes at both doses of diazepam; at higher dose directed exploration was decreased in the normotensive males. Diazepam shows no effect in the between-session habituation of directed exploration in the normotensive rats of both sexes; in the genetically hypertensive rats instead of the between-session habituation of directed exploration, in the second session (relative to the first one) there appeared elevation of directed exploration.