摘要
Stressful events during certain neonatal periods may increase the vulnerability of an individual to develop psychopathology and/or drug dependence later in life. Therefore, in the present study, we assessed activity levels, emotionality, sensitivity to the effects of morphine, as well as expression of proenkephalin and prodynorphin in several brain regions in 35 and 90-day-old male mice, subjected to postnatal manipulation consisting in brief exposures to clean bedding (CB). In comparison with controls, CB mice showed reduced emotionality expressed as percentage of time in open arms of the elevated plus maze both at 35 days of life and in adulthood. Increased nociceptive threshold was also present in both time points measured. Conversely, higher locomotor activity was recorded in 35 days of life but not in adulthood. Analysis of film autoradiograms revealed no changes in prodynorphin mRNA level, but statistically significant decrease in the level of proenkephalin mRNA in striatum in young CB mice in comparison with young controls; no difference was observed between adult CB and control animals. CB adult mice also showed hypersensitivity to the rewarding effect of morphine in comparison with controls in the place preference test. In conclusion, our results revealed that in the critical period of development the effects of manipulation were evident, not only on behavioral responses but also on the neurochemical markers considered in the present research. Postnatal manipulation could induce changes in the dynamic neuronal processes occurring during development with long-term behavioral effects.
摘要译文
某些新生儿期间的压力事件可能会增加个体在以后生活中发展精神病理学和/或药物依赖的脆弱性。因此，在本研究中，我们评估了活动水平，情绪，对吗啡作用的敏感性，以及在35和90日龄雄性小鼠的几个大脑区域中的脑啡肽和前体啡肽的表达，进行了产后操作。短暂暴露于干净的床上用品（CB）。与对照相比，CB小鼠表现出降低的情绪，表示为在生命的35天和成年期的高架十字迷宫的开放臂中的时间百分比。在测量的两个时间点中也存在增加的伤害感受阈值。相反，在35天的生命中记录到更高的运动活动，但在成年期没有记录。对照片放射自显影图的分析显示，与年轻对照相比，年轻CB小鼠的前体蛋白mRNA水平没有变化，但纹状体中脑啡肽原mRNA水平的统计学显着降低;在成年CB和对照动物之间没有观察到差异。与位置偏爱试验中的对照相比，CB成年小鼠也显示出对吗啡的奖赏效果的超敏反应。总之，我们的研究结果表明，在发育的关键时期，操作的影响是明显的，不仅对行为反应，而且对本研究中考虑的神经化学标记也是如此。产后操作可以诱导发育期间发生的动态神经元过程的变化，具有长期的行为效应。
Francesca R.D'Amato[a];ElenaBarakos[a];BarbaraZiolkowska[b];IlonaObara[b];BarbaraPrzewlocka[b];FlaminiaPavone[a];. Mild postnatal manipulation reduces proenkephalin mRNA in the striatum in developing mice and increases morphine conditioned place preference in adulthood[J]. Pharmacology Biochemistry and Behavior, 2007,87(1): 122-129