SELECTIVE EFFECTS OF 8-OH-DPAT ON SOCIAL COMPETITION IN THE RAT

Previous research has demonstrated that dominant-subordinate relations hips measured in small groups of rats competing for access to palatabl e food or fluids can be disrupted by both anxiolytic and anxiogenic dr ugs, and it has been proposed as a possible animal model of anxiety. T he present study investigated the effects of the selective 5-HT1A agon ist 8-OH-DPAT on the rank order of triads of rats measured in terms of access to sweetened milk. The effect of 8-OH-DPAT on locomotor activi ty and intake of sweetened milk was also determined. 8-OH-DPAT (25 and 37.5 mu g/kg) significantly increased the subordinate animals positio n in the social hierarchy without effect on the individual intakes of sweetened milk or locomotor activity. The same doses administered to d ominant animals had no effect on any of the parameters measured. The 8 -OH-DPAT-induced increase in social competition in subordinate rats wa s dissociable from effects on feeding behavior and locomotor activity. The results from this study provide further evidence that social comp etition in groups of rats may represent a model that can be used to de tect drugs acting via receptor mechanisms believed to be implicated in anxiety.