Participation of apoptotic proteins in hypothalamic regulation of volume of population of the red-backed vole Clethrionomys rutilus

The content of the antiapoptotic protein Bcl-2 and of the proapoptotic enzyme caspase-3 in the paraventricular nucleus (PVN) of sexually immature red-backed voles is studied in the course of the population cycle. The significant change of the Bcl-2 and procaspase-3 in the PVN neurons is established at all cycle phases. The low volume of population (under the most favorable conditions of the existence of the animals) is revealed to be characterized by the moderately increased or high expression of the Bcl-2 protein alongside with low or moderately increased caspase-3 activity. This is suggested to provide the PVN adequate reaction at the low population volume. At high population volume (under conditions of increased stress in the overcrowded population at the phase of peak and especially of fall), a significant decrease of the Bcl-2 expression is established with simultaneous increase of the caspase-3 activity. The disbalance in synthesis of apoptotic proteins seems to lead to disturbances of PVN functions at phases of peak and fall and, as a consequence, to a decrease of adaptive possibilities of these animals, which might be one of important causes of essential elimination of the animals at the autumn-winter period.