Abstract: To explore the effects of adrenoceptor antagonists, propranolol and prasozin on chronic unpredictable mild stress (CUMS) rats, serum corticosterone (CORT)level and hippocampal inducible nitric oxide synthase level(iNOS) following acute stress. MethodsThirtytwo Wistar male rats were randomly divided into four groups： the control group, the CUMS group, the propranolol group and the prasozin group. The behavior of all rats was determined in an openfield test before and after CUMS. Animals were sacrificed by decapitation 2h after an acute stress of 1.0?mA, 5?s, persisting 60 times. The content of serum CORT was evaluated by cortisol RIA, and iNOS was measured by western blot. ResultsCompared with the controls, the propranolol group exhibited a decreased square crossing number, rearing score and grooming number(P＜0.05) and an increased iNOS level in the hippocampus(P＜0.01). There was no statistical difference between the prasozin group and the control group. Serum corticosterone of the prasozin group was higher than that of the propranolol group(P＜0.05). ConclusionsPrasozin could improve the behavior of CUMS rats and upregulates the CORT level after exposure to acute stress, it also reverses impairment of the hippocampus produced by stress. Although propranolol could alleviate anxiety in stress, it could not reverse the impairment of the hippocampus produced by stress.

Key words: Chronic unpredictable mild stress, Stress, Corticosterone, Nitric oxide synthase, Rats,Wistar