慢性应激模型大鼠脑内5-HT1A受体表达分析

Expression of 5 -- HT1A receptors in the brain of chronic unpredictable mild stress model in rats

目的探讨慢性不可预见性轻度应激（CUMS）模型大鼠各脑区（海马、中缝核、前额叶及纹状体）5=HT1A受体表达及与旷场行为变化的关系；西酞普兰对5-HT1A受体表达的影响。方法将24只雄性SD大鼠随机分为3组（n=8）：A组为对照组；B组为CUMS应激组；C组为CUMS应激＋西酞普兰用药组（每天腹腔注射西酞普兰水溶液2m1，10mg／kg）。实验为期6周，通过旷场试验评价大鼠行为，6周后处死大鼠获取脑组织，采用Real—TimePCR检测各脑区5-HTlAmRNA表达水平，并分析其与矿场行为的相关性。结果B组海马5HT1AmRNA表达较A组有增高趋势（P=0．05），其余各脑区5-HT-AmRNA表达均差异无统计学意义（P〉0．05）。海马5-HT1AmRNA表达大鼠移动次数、转身次数呈正相关，与总不动时间呈负相关；中缝核、纹状体5-HT-AmR—NA表达与中心移动距离呈正相关，纹状体5-HT1AmRNA表达与中心停留时间呈正相关（P均〈0．05）。结论慢性应激可能会引起海马5-HT1A受体表达增高；抗抑郁剂西酞普兰对5-HT1A受体表达无影响。5-HT1AmRNA表达与旷场行为变化有相关性。

Objective To explore the expression of 5--HTIA receptors in different areas of brain （hippocampus,raphe nuclei,prefrontal lobe and striatum） in rats with chronic unpredictable mild stress （CUMS）, and its correlation with behavior changes in open field tests. To investigate the effect of citalo- pram on expression of 5-- HT1A receptors in the model. Methods Twenty-- four male SD rats were ran- domly assigned to control group （group A）, CUMS group （group B） and CUMS4-citalopram group （in- traperitoneal injection of citalopram 2 ml/d, 10 mg/kg） （group C） , with 8 rats in each group. The ex- periment lasted for 6 weeks. Behavior of rats was assessed through open field tests before model estab- lishment and 6 weeks after model establishment. Animals were sacrificed after 6 weeksand brain tissues were obtained. Real--Time PCR was employed to detect the expression of 5--HT1A mRNA in different areas of brain. Results Compared with group A, there was a trend of increase of 5-- HT1A mRNA in hippocampus in group B （P = 0.05）. 5 HT1A expression in other areas of brain showed no significant difference among groups （P ~〉 0.05）. The expression of 5- HT1A mRNA was significantly correlated to changes in open field tests （P ~ 0.05）. Conclusions Chronic stress might increase the expression of 5-- HTIA mRNA in hippocampus. Citalopram had no significant effects on the expression of 5--HT1A mR NA in different areas of brain in rats. There was significant correlation between the expression of 5- HT1 A mRNA and behavior changes in open field tests.