[The neurochemical characteristics of rats differing by their behavior in the emotional resonance test. Free-radical processes and lipids of the cerebral cortex in older rats].

Free radical processes and lipid content in brain membranes were investigated in old male Wistar rats with differences in individual behaviour in "emotional resonance" test. Two groups of rats were selected, i.e. 1--which stayed for more than 2/3 of the total test time in the dark part of the experimental chamber and 2--which spent the total test time in the light part of the chamber. Free radical processes and lipid content in the cortex of the left and right brain hemispheres did not differ in control animals of groups 1 and 2. Acute immobilization stress induced changes of the studied parameters depending on behavioural type. Rats of group 2 were more reactive than those of group 1.