Patki Gaurav, Atrooz Fatin, Alkadhi Isam, Solanki Naimesh, Salim Samina
Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX 77204, USA.
Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, TX 77204, USA.
Neurosci Lett. 2015 Jan 1;584:308-13. doi: 10.1016/j.neulet.2014.10.051. Epub 2014 Nov 1.
The social defeat paradigm involves aggressive encounters between Long-Evans (L-E) (resident) and Sprague-Dawley (S-D) (intruder) rats. Successful application of chronic social defeat stress in S-D rats is dependent upon selection of highly aggressive L-E rats. Half of the L-E rats screened for aggression did not meet the criterion for aggression (L-E rats performing a defeat, characterized by the intruder surrendering or acquiring a supine position for at least 3s). The observation of the differences in the level of aggression between age and weight matched L-E rats was quite compelling which led us to the present study. Herein, we measured behavioral differences between aggressor and non-aggressor L-E rats. We analyzed their anxiety-like behavior using open-field and elevated plus maze tests. We also measured aggression/violence-like behavior using two tests. In one, time taken to defeat the intruder S-D rat was recorded. In the second test, time taken to attack a novel object was compared between the two groups. We observed a significant increase in anxiety-like behavior in aggressor rats when compared to the non-aggressive group. Furthermore, time taken to defeat the intruder rat and to attack a novel object was significantly lower in aggressive L-E rats. Biochemical data suggests that heightened anxiety-like behavior and aggression is associated with increased plasma levels of corticosterones and elevated oxidative stress. Significant alterations in dopamine (DA), norepinephrine (NE) and epinephrine (EPI) were observed within the hippocampus, amygdala, and the prefrontal cortex, suggesting potential involvement of dopaminergic and noradrenergic systems in regulation of aggressive behaviors.
社会挫败范式涉及长 Evans（L-E）（常住）大鼠和斯普拉格-道利（S-D）（入侵者）大鼠之间的攻击性遭遇。在 S-D 大鼠中成功应用慢性社会挫败应激取决于选择高度攻击性的 L-E 大鼠。筛选出的用于攻击行为的 L-E 大鼠中有一半不符合攻击标准（L-E 大鼠实施挫败行为，特征为入侵者投降或仰卧至少 3 秒）。对年龄和体重匹配的 L-E 大鼠之间攻击水平差异的观察非常引人注目，这促使我们开展了本研究。在此，我们测量了攻击性和非攻击性 L-E 大鼠之间的行为差异。我们使用旷场试验和高架十字迷宫试验分析了它们的焦虑样行为。我们还使用两项试验测量了攻击/暴力样行为。在一项试验中，记录击败入侵者 S-D 大鼠所需的时间。在第二项试验中，比较了两组攻击新物体所需的时间。与非攻击组相比，我们观察到攻击大鼠的焦虑样行为显著增加。此外，攻击性 L-E 大鼠击败入侵者大鼠和攻击新物体所需的时间显著更短。生化数据表明，焦虑样行为和攻击性增强与血浆皮质酮水平升高和氧化应激增加有关。在海马体、杏仁核和前额叶皮质中观察到多巴胺（DA）、去甲肾上腺素（NE）和肾上腺素（EPI）有显著变化，表明多巴胺能和去甲肾上腺素能系统可能参与攻击行为的调节。
