Abstract: The effect of exposure to emotional stress on the primary humoral immune fun ction(antiovallum antibody level and spleen index), the endocrine response (cort icosterone level, epinephrine and norepinephrine levels), the behavioral changes (exploring, grooming and attacking behavior) was studied in adult male Wistar r ats. Emotional stress was induced by randomly giving empty water bottles to rats trained to drink water at two set times each day. Emotional stress were given 1 4 times, ten minutes per each time during experimental period. Results showed th at firstly, empty water bottles induced significant attacking behavior (biting t he empty water bottle and cage shed) in rats of emotional stress group, secondly emotional stress decreased the weight of the spleen and the level of specific a nti-OVA IgG antibody and increased the levels of epinephrine, norepinephrine and corticosterone. A negative correlation between antibody levels and level of nor epinephrine was also found. Together with the previous work in our laboratory, t he results demonstrated that emotional stress suppressed the specific primary hu moral immunity of rats. The sympathetic nervous system may be involved in this immunomodulation.

Key words: emotional stress, antibody, norepinephrine, epinephrine, corticostero ne