Assessment of anxiolytics (4)--Social interaction test

Abstract:  The rat social interaction test is based on spontaneous social interaction behaviors, such as sniffing and following between two rats, and thus does not necessitate noxious food or water deprivation, electric shocks and lengthy training. The amount of time that pairs of rats spent interacting with each other varied systematically with the environmental stimuli, such as the illumination and familiarity of the test arena. When tested under the most aversive high light: unfamiliar condition, control subjects exhibited low levels of social interaction. Acute treatment with benzodiazepine-relat ed agents exerted anxiolytic effects, as measured by an increase in the time spent by pairs of rats engaged in social interaction, while anxiogenic agents decreased social interaction under the same high light: unfamiliar condition. The minimum effective doses of benzodiazepine-relat ed agents in this paradigm corresponded well to their respective clinical dosages. Thus, the simple social interaction test is beneficial in assessing effects of agents on the anxiety states of animals in a qualitative and quantitative manner. Treatment with 5-HT-related anxiolytic agents also increased social interaction. However, there existed some differences in the magnitude of increases or characteristics of each behavioral component between benzodiazepine- and 5-HT-related agents, which were consistent with the clinical literature regarding their efficacy in the treatment of anxiety disorders. Therefore, the rat social interaction test is predictable for clinical anxiolytic effects of non-benzodiazepine agents in comparison with benzodiazepines.