普萘洛尔和哌唑嗪对应激大鼠的保护作用

Propranolol and prasozin protect rats against stress

目的观察肾上腺素能受体拮抗剂普萘洛尔和哌唑嗪对慢性轻度不可预知应激模型(CUMS)大鼠行为学及急应激暴露后血清皮质酮水平(CORT)、中枢海马诱导型一氧化氮合酶(iNOS)表达的影响,探讨其应激保护作用。方法健康成年Wistar雄性大鼠32只,随机分为4组:空白对照组、CUMS组、普萘洛尔组和哌唑嗪组。CUMS造模前后,用旷场实验测各组大鼠的行为学变化。造模结束后,应激动物接受1.0 mA,5 s,持续60次的急性电击刺激,2 h后断头处死。放射免疫分析法测大鼠血清皮质醇含量换算成皮质酮含量;Western blot测中枢海马中iNOS表达量。结果与对照组比较,普萘洛尔组大鼠水平运动得分、竖立次数和修饰次数减少(P<0.05),中枢海马iNOS表达量明显增加(P<0.01);哌唑嗪组大鼠与对照组比较无明显差异,血清CORT水平明显高于普萘洛尔组(P<0.05)。结论哌唑嗪可明显改善CUMS模型大鼠的行为学改变,有利于应激个体再次遭遇急性应激时CORT的调动,减轻应激导致中枢海马损伤的程度。普萘洛尔可缓解应激时的焦虑水平,但不能扭转应激对中枢海马的损伤。

Objective 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. Methods Thirty-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 cortisel RIA, and iNOS was measured by western blot. Results Compared 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 cortieostemne of the prasozin group was higher than that of the propranolol group （ P 〈 0.05）. Conclusions Prasozin could improve the behavior of CUMS rats and up-regulates the CORT level after exposure to acute stress, it also reverses impair- ment 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.