The volume of the extracellular matrix rises along with the age increase. The presence of intercellular junctions and the exchange processes of electrical impulses and ion currents carried out via them is a critical component in the functioning of cardiomyocytes (both primary and secondary). The intercalated discs may engage in compensatory-adaptive responses resulting from age-related involutional processes, as evidenced by an increase in their quantity in the hearts of older rats. The structural integrity of the intercalated discs in young and middle-aged rats may be directly correlated with the highly functional capabilities of the heart muscle. It would be interesting to conduct a more in-depth study of the intercalated discs using immunohistochemical techniques and a comparative analysis of disc histological structure in rats of various ages by extrapolating the findings on the functional capabilities of cardiomyocytes.