ABSTRACT
The increase of stress following technology development appears to be a threat to human body organs such as nervous system. The present study was conducted aiming at investigating the effects of chronic multiple stress on morphometric changes of Betz cells in male rat cerebral cortex. In this experimental study, 18 Wistar rats were randomly divided into two equal groups. Animals of the under stress group for 10 days were exposed to different stresses, such as food deprivation, water deprivation, forced swimming, immobilization at 4[degree]C, and isolation, while the animals in control group were kept in their cages without any intervention. After the intended period, the animals were anesthetized and then their brains were removed. After fixation, samples of frontal cortex of the brain were prepared for light microscopy study. The data analysis were performed using t-test, and the significance level was considered p<0.05. The mean number and size of Betz cells in the stress groups was significantly lower compared to control group [p<0.001]. The qualitative observations also showed chromatolysis of nissl bodies, nucleus condensation, and decrease of neural processes. The results of the present study showed that chronic multiple stress can have negative effects on the rat cortical internal pyramidal layer through reducing the size and number of Betz cells; however, more studies are needed to confirm the above results.