Can social and agonistic interactions be used to detect anxiolytic activity of drugs?

Majority of adult male albino random-bred mice housed singly or in small groups show agonistic behavior on interaction with a strange male mouse: some of them are predominantly aggressive ('aggressive' mice) while others show defenses or escapes even though their partners are not aggressive ('timid' mice). The remaining males not exhibiting agonistic behavior ('sociable' mice) show more social investigation then aggressive or timid mice and more locomotion then timid mice. Active defensive-escape behavior ('timidity') and inhibition of social investigation and of locomotion is much stronger in an unfamiliar cage with a strange male than in a home cage or on interaction with a female. Effects of 50 drugs on behavior of aggressive and timid male mice on agonistic interactions with non-aggressive male mice in neutral cages were tested. Most of the drugs possessing anxiolytic activity in man reduced active escapes or defenses at doses lower than those inhibiting attacks or locomotion and increased social investigation while most drugs without anxiolytic activity did not show these effects. Some anxiolytic drugs reduced tail-rattling (an ambivalent activity presumably reflecting both attack and escape tendency) at doses lower than those reducing attacks and increased locomotion. Only some benzodiazepines (nitrazepam, oxazepam and diazepam) produced the whole spectrum of these effects indicating a reduced defensive-escape tendency. The present results suggest that a selective inhibition of defensive-escape tendency on agonistic interactions can be a good predictor of anxiolytic activity of drugs. Profiles of effects of seven benzodiazepines in the present model of agonistic interaction to some extent differed: triazolam, clonazepam and flunitrazepam were more sedating (reduced timidity only at doses inhibiting locomotion) while nitrazepam, oxazepam, diazepam and chlordiazepoxide were less sedating (reduced timidity at non-sedative doses, stimulated social investigation and locomotion). Only drugs stimulating GABA-receptor complex (benzodiazepines, barbiturates and GABAergic drugs) inhibited active escapes and defenses at doses lower than those reducing attacks. This suggests that the GABA-receptor complex is involved in regulation of defensive-escape tendency in intraspecies conflict.