Possible autoimmune mechanisms of regulation of rat behavior in the “open field” test

Abstract

BACKGROUND: In recent years, researchers have demonstrated interest in the autoimmune mechanisms of regulation of physiological processes. In response to damage or protein expression, the levels of autoantibodies increased to ensure the restoration of the disturbed balance. Levels of autoantibodies are high in many diseases. AIM: The aim of this study was to assess the levels of autoantibodies in the blood serum of experimental animals and evaluate their behavior in the open field test. MATERIALS AND METHODS: Of 32 male rats, two groups were formed: group 1 was not exposed to stress, whereas group 2 was subjected to stress for 7 days by applying a clamp on the skin fold for 15 min daily. Three days after the last stress procedure, testing was conducted in the open field. After assessing the behavior, blood serum was obtained, and the levels of autoantibodies to dopamine receptors (DR1 and DR2) and NMDA receptors (NR1, NR2A, and NR2B) were determined. RESULTS: Compared with group 1, group 2 visited the central zones of the field less often, had lower vertical activity, and less often performed acts of washing. In group 2, the levels of autoantibodies to DR1 and DR2 were higher, but to NR2B were lower. Correlation analysis revealed that in group 2, the level of autoantibodies to DR2 was associated with horizontal activity (r = 0.60). In group 1, a relationship was established between the level of autoantibodies to NR2B and the number of runs through the central zones of the field (r = +0.68). CONCLUSIONS: Taking into account the revealed relationship between the levels of autoantibodies and activity in the open field, the degree of increase in blood IgG titers to DR2 receptors may reflect the severity of changes in the behaviors of animals under stress. Conversely, in connection with the emerging data on the possibility of IgG penetration through the bloodbrain barrier, the effect of autoantibodies on brain dopamine receptors with a limited activity of the dopaminergic system may be considered.