Cognitive deficiency induced by the acute stress in rats: a possible role of brain catecholaminergic systems

The evaluation of the male albino rats cognitive capacity was performed by placing the animals in glass cylinder plundged into water (22 degrees C.) In order to escape from that stress situation the rat should dive under the cylinder's edge, solving by this way the extrapolatory escape task (EET). Two groups of rats (A and B) have been selected and characterized within the total laboratory population. The A rats have shown a smaller number of attempts to achieve successful escape and a shorter latency of that reaction in comparison with the B animals. The latter displayed a higher behavioral activity in "open field" test. The combination of 100 mg/kg L-DOPA with 25 mg/kg of benzerazide (DOPA-BENZ) was shown to impair dramatically the cognitive capacity of the two groups of animals. DOPA-BENZ treated rats failed to demonstrate any correct solution of EET. The rats of the two groups were distinguished clearly in terms of dopamine contents and turnover rate measured in three brain areas by the HPLC technique. Among psychotropic drugs studied only haloperidol and fluphenazine were found to restore partially the animals capacity to cope with the EET after DOPA-BENZ administration.