| Abstract: | The influence of chronic stress on the ultrastructure of the myocardium and hypothalamus was studied in experiments on male rats with different levels of emotional-behavioral reactivity. "Emotional" rats manifested a pronounced increase in glycogen granules in myocytes and intercellular space, appearance of the areas of overcontraction of myofibrils, conglomerates of aggregated platelets in myocardial capillaries, and red cell egress from myocardial and hypothalamic capillaries. Alterations in the ultrastructure of the myocardium and hypothalamus in "nonemotional" rats were less marked and consisted in the appearance of the areas of overcontraction of myofibrils, enlargement of sarcoplasmic reticulum caverns, and in an increase in the lipid content in cardiomyocytes. The ultrastructural changes in the myocardium and hypothalamus of "emotional" and "nonemotional" rats indicate different reactivity of the animals and are likely to be accounted for by different levels of activation of their adrenergic systems. |
