Cooperative effects of expression of apoptosis-regulating genes in formation of spatial memory

Abstract

The aim of this study was to compare features of simultaneous expression of apoptosis genes, Bax, Dffb, and Casp-3, Casp-8, and Caps-9, in the hippocampus, prefrontal cortex, and cerebellum under the conditions of forced swimming (control) and during Morris water maze training for spatial skills in adult Wistar rats.
Methods. To develop long-term spatial memory, the behavioral model of Morris water maze was used. Genetic studies were performed on the relevant brain structures, the hippocampus, prefrontal cortex, and cerebellum, of rats with formed spatial memory. The expression of Bax, Dffb and Casp-3, Casp-8, and Casp-9 genes was measured with real-time PCR in these cerebral structures.
Results. Physical activity and stress were found to exert a suppressive effect on the apoptosis-regulating genes in the hippocampus as compared to control animals. In the prefrontal cortex and cerebellum, the Casp-3 gene was activated, which may indicate participation of the Casp-3 enzyme in neuroplasticity of cell rearrangements rather than in apoptotic reactions upon suppressed expression of the other studied genes, Bax, Dffb, Casp-8, and Casp-9. In animals trained for the navigation skill, the formation of hippocampus-dependent spatial memory was associated with activation of the Casp-9, Casp-3, and Bax genes in the hippocampus compared to the “passive swimming” control. In the prefrontal cortex of trained animals, a pronounced increase in the expression of all apoptosis-regulating genes was noted. The cerebellum of rats with formed spatial memory
showed a significant activation of the Casp-9, Bax, and Dffb genes.
Conclusion. The study showed cooperative effects of the expression of apoptosis-regulating genes in the brain of animals with the hippocampus-dependent spatial memory formed in the Morris water maze.