Effects of Psychological Stress on Central Dopaminergic Neurons

: Objective — To evaluate the effects of psychological stress on central dopaminergic neurons. Methods — A test group of 90 rats was subjected to psychological stress for 30 minutes a day for 14 days. The rats were divided into three groups, and treated with tyrosine 250mg/kg, 500mg/kg, 1000mg/kg per day, 30 rats as psychological stress group and 30 rats as control group. After stress, TH and fos protein immunohistochemical staining were carried out on the relevant brain tissue sections of VTA (lateral tegmental area), Nac (nucleus accumbens) and mPFC (prefrontal cortex), and the results of TH immunohistochemical staining, Fos protein immunohistochemical staining and Fos/TH double staining were analyzed. Results — In VTA, the number of TH positive neurons in stress group was lower than that in control group (P<0.05), and the number of TH positive neurons in 500mg/kg and 1000mg/kg tyrosine groups was higher than that in stress group (P<0.05). The expression of Fos protein in VTA, mPFC and Nac of control group was lower than that of stress group, and the expression of Fos protein in VTA, mPFC and Nac of 500mg/kg and 1000mg/kg tyrosine groups was lower than that of stress group (P<0.05). Conclusion — Repeated psychological stress can damage central dopaminergic neurons, decrease the number of TH positive neurons and increase the expression of Fos protein. Tyrosine, the precursor of dopamine, can effectively control the damage.