Abstract: The aim of study was to investigate the effects of chronic emotional stress and physical stress on behavior and protein levels of neurogranin in brain, and the correlation between protein levels of neurogranin and stress-induced behavioral changes. Forty rats were randomly divided into emotional stressed group (ES), physical stressed group (PS), regular drinking group (C1) and handled-controls (C2), with ten in each. Randomly giving empty water bottles was used as emotional stressor, and physical stress is induced by water-deprivation. Behavioral changes in rats after stress were observed by open-field test, and neurogranin level of hippocampus and forebrain were determined by Western blotting. The results showed that there is no significantly difference in neurogranin levels of hippocampus among four groups. Neurogranin level of forebrain in ES was significantly lower than that in C1 and C2 groups (p<0.05, p<0.01;separately). Neurogranin level of forebrain in PS was significantly lower than that in C1 (p<0.05). Grooming in open-field test in both ES and PS groups was more increased than that in C2 group (p<0.01, p<0.05;separately). Correlation is significant at 0.01 level betweengrooming and neurogranin level in forebrain. These results suggested that chronic emotional stress can induce more significant decrease in neurogranin levels of forebrain and increase in grooming than physical stress. Grooming may be a sensitive behavioral index, and neurogranin levels of forebrain may be an effective biological predictor for anxiety and/or depression induced by emotional stress.

Key words: emotional stress, physiological stress, hippocampus, frontal cortex, behavior, neurogranin