Summation of subthreshold impulses in case of separate and combined effects of cadmium and immobilization stress, considering typology of behavior of experimental animals

The aim of the work was to study dynamics of changes of summation-threshold index under the combined impact of cadmium and immobilization of animals depending on the typological characteristics of animal behavior. The studies were conducted on white rats, previously divided into groups of active and passive ones by terms of "horizontal activity" in the test "open field". In each group the experiments were planned according to the scheme of orthogonal design 22. Summation-threshold index was studied by Speransky S.V. method. It was found that the summation-threshold index increases on the day 10 of experiments under the action of a cadmium only in groups of "active" and "passive" animals; this testifies to inhibition processes in the CNS. The effect of cadmium, immobilization and their combined action on day 30 of experiments leads to the reduction in the of studying parameter in both groups of animals; this testifies to excitation of the CNS. The active animals are more susceptible to immobilization stress, the passive ones ? to the action of cadmium. The combined action of stress factors on day 10 is characterized by desensitization, on day 30 ? by unidirectional interdependent action and less than by additive effect. The processes of inhibition and excitation in the central nervous system depend on type of animal behavior, type and duration of exposure to the stress factor. The results may be taken into account when assessing adaptation process, correction, and adaptation depending on the type of behavior.