Effects of diazepam and buspirone on the behaviour of wild voles (Microtus socialis) in two models of anxiety.

Exploration models of anxiety rely almost universally on the use of laboratory species. Furthermore, the spontaneous patterns of locomotion displayed are often interpreted as being an expression of antipredator defense. However, there is no direct link between the experience of these animals and the proposed motivation for their behaviour. To address this problem, the behaviour of wild trapped voles (Microtus socialis), a small-rodent species that is heavily predated upon, was examined in the elevated plus-maze and the black/white exploration model. It was hypothesised that the patterns of locomotion in these exploration models of anxiety should be similar to those reported for laboratory animals if the reactions of the laboratory animals are related to antipredator defense. Data revealed that voles show a similar preference for the protected areas in these models (closed arms or dark section) and that this preference can be modified by buspirone and diazepam. Interestingly, although the effective doses of each drug was the same within each model, it differed between models, with the minimum effective doses of these compounds being lower in the black/white exploration model (1 mg/kg) than in the elevated plus-maze (4 mg/kg). These data provide valuable information concerning the actions of anxiolytic compounds in wild trapped animals as assessed by formal laboratory models and provide useful verification that findings in these models may be generalised to species other than laboratory rodents.