Abstract: | Ultrastructural organization of chromaffin cells of rat adrenal glands was studied in different stress models (48 h of running in the wheel, 48 h of immobilization, and sleep deprivation during 7 days). It was shown by ultrastructural morphometry that chromaffin cells experienced fine structural modifications (a decrease in the number of adrenaline- and noradrenaline-containing granules, swelling of mitochondria and endoplasmic reticulum). The degree of such modifications depended on a stress situation, being more pronounced during physical stress. |