A comparative analysis of learning and exploratory behavior in rats with different resistances to stress exposures and to the brain monoamine level]

Wistar rats stable (S) to sound stimulus differed from the unstable (NS) ones by a heightened investigatory activity in condition of moderate stress in the open field test, by heightened reactivity to sensory stimuli of various modalities (somatosensory, visual and olfactory), lowered level of investigatory behaviour in the test of burrow chamber. S-rats differed from NS-animals by a higher ability to learning of goal-directed reaction and a lower ability to discrimination of different emotional influences. The results of biochemical analysis of the content of biogenic amines in various brain structures revealed in stable rats an increase of noradrenaline level and in non-stable ones--a higher level of dopamine and serotonin.