[Age-related changes in the cardiomyocyte population of the heart ventricles of white rats].

The total number of muscle cells and their nuclei in the rat ventricle walls at the age from 3 to 30 months was counted by means of alkaline dissociation of the prefixed myocardium. The total number of cardiomyocytes and their nuclei was shown to increase on the second year of life, this increase being much more pronounced and attaining the maximum much earlier in the right ventricle than in the left one. At the senile age (30 months) the number of cardiomyocytes in the ventricles decreases but the mean size of cells increases.