血清褪黑素在早期环境对大鼠情绪发展中的作用

Effect of serum melatonin on emotional behavior of rats in early environment

【目的】通过研究早期环境对大鼠情绪反应及血清褪黑素(melatonin,MT)水平的影响,探讨早期环境对远期行为影响的可能机制。【方法】将45只新生雄性SD大鼠随机分为丰富环境及早期刺激(the enriched environment and early intervention,EE)组、隔离环境(the isolated environment,IE)组和正常对照组。EE组和IE组于生后第1～28天接受不同环境刺激(丰富环境、隔离环境),于生后第29天采用触动实验评价大鼠情绪行为及放射免疫学方法测定大鼠血清MT水平改变。【结果】1)触动实验结果显示,EE组大鼠紧张性触动、疼痛刺激评分分别为(1.13±0.35,1.87±0.83)>对照组(1.67±0.72,2.60±0.91)>IE组(2.13±0.64,3.47±0.64),P<0.05;2)血清褪黑素水平:EE组[(49.67±6.67)ng/mL]>正常对照组[(45.81±4.09)ng/mL]>IE组[(40.53±3.23)ng/mL],差异有高度统计学意义(F=13.021,P<0.001);3)血清褪黑素水平与大鼠紧张刺激、疼痛刺激呈负相关性(P<0.05)。【结论】褪黑素在调节早期环境对发育期动物情绪发展的影响中起重要作用。

[Objective] To explore the influence of early environment on emotional behavior of rats and the involved melatonin pathway. [Methods] The different environments-the enriched environment （EE） , the isolated environment （IE） for rats were established. The the head-touch test was performed to assess anxious and nervous ability of the rats after postnatal 29 days（P29）. The levels of serum melatonin of rats were tested by the emission immunology method after early environment intervention. [Results] 1） In the handle-touch test, the scores of nervous and the pain in EE group were （1.13±0.35,1.87±0.83）〉 the normal control group（1.67±0.72,2.60±0.91）〉 the isolated environment group（2. 13 ±0.64,3.47±0.64） （P〈0.05）. 2） The level of serum melatonin of rats in EE group was（49.67±6.67）ng/mL,which was more than that in control group（45.81±4.09） ng/mL. The level of serum melatonin in IE group was （40.53±3.23）ng/ mL, which was the lowest among three groups（P〈0. 001）. 3） There was negative correlation between melatonin levels in rats with stressors,pain stimulation. [Conclusion] The melatonin may play an important role in emotion development, which regulated by the early environment.