ETHOLOGICAL STUDY OF THE EFFECTS OF TETRAHYDROAMINOACRIDINE (THA) ON SOCIAL RECOGNITION IN RATS

Two major difficulties confront ethopharmacological investigations on cognitive abilities such as social recognition in drug-treated animals involved in free social interactions. The first concerns the choice o f the most relevant behaviours, those reflecting the cognitive abiliti es attributed to the animals and assessing the specificity of the drug activity, and those reflecting non-specific drug effects. The second refers to the experimenter's awareness that in contrast to physical ob jects, social stimuli respond to drug-treated subjects and that their own level of responsiveness may influence the changes of drug-treated subjects' social interest. In addition, their contribution may vary ac cording to the different treatments the drug-treated subjects receive. In examining the effects of tetrahydroaminoacridine (THA) at doses of 0.3, 1 and 3 mg/kg on the ability of adult male rats to recognize pre viously encountered conspecifics, we attempted to take into considerat ion such difficulties. A detailed behavioural profile of drug-treated rats was reported to separate specific from non-specific effects of TH A. In addition, rats were assigned an index of responsibility for cont act which takes into account the interactive dimension of each dyad an d allows relevant comparisons between different treatments. The doses of THA which were found to decrease the duration of exploration of a f amiliar juvenile were also found to decrease the number of contacts in itiated by the drug-treated subjects. THA induced a relative increase in body care by comparison to saline treatment. However, it had no eff ect of locomotor activity and rearing of the subjects. These findings enable dissociation of the effects of THA on cognitive versus non-cogn itive processes.