Numerical density of neurons in the hippocampus of rat lines contrasting in excitability of the nervous system exposed to prolonged emotional painful stress

: Two lines of rats, selected according to the excitability of nervous system to the action of an electric current, served as the model objects to study the changes of numerical density of neurons in hippocampus area CA3 24 hours, 2 weeks, 2 and 6 months after prolonged exposure to emotional painful stress. Reduction of neuron density in hippocampus area CA3 was demonstrated after exposure to stress that persisted as long as 6 months. These changes developed following time intervals that were different for each line of rats (24 hours for rats with low excitability and 2 month--for rats with high excitability). Thus, it was demonstrated for the first time, that prolonged differential effect of stress on numerical density of neurons in hippocampus area CA3, that plays an important role in the processes of learning and memory, depends on genetically determined constitutional peculiarities of the nervous system.