Possible relationship between polyamines and traumatic stress: Changes in polyamine levels after weter-immesdion restraint stress in mouse brain

我们和其他人之前的研究表明，癫痫大脑中的神经元应激和损伤显著改变了多胺代谢，导致腐胺水平显著升高。最近也有报道称，脑多胺代谢受创伤应激影响，可能与情感性障碍有关。本研究通过测定浸泡约束应激后额叶皮质、海马、下丘脑和血浆中的多胺水平，进一步阐明多胺与创伤应激的关系。应激小鼠置于约束应力笼中，浸泡在25℃的水中2h。分别于应激停止后5min、6h、24h、48h进行斩首。应激24小时后，脑各部位腐胺水平均显著升高。应激后6h和24h，额叶皮层和下丘脑的亚精胺和精胺水平保持不变或略有降低。在应激作用后，血浆中多胺水平在任何时间间隔内均无变化。在没有水浸泡的约束应激情况下，腐胺水平仅在额叶皮层增加。地西泮（5mg/kg，每日1次）预处理可降低应激诱导的多胺变化。这些结果表明，多胺代谢的变化与创伤应激有关，其幅度似乎与应激源的强度有关。

Previous studies, by others and by us, have shown that neuronal stress and injury in the epileptic brain significantly alter polyamine metabolism, resulting in a marked elevation of the putrescine level. Recently, it was also reported that brain polyamine metabolism is modified by traumatic stress and may be involved in affective disorders. In this study, we measured the polyamine levels in the frontal cortex, hippocampus, hypothalamus, and plasma after applying water-immersion restraint stress, to further clarify the relationship between polyamines and traumatic stress. To stress mice, they were confined in a restraint stress-cage and immersed in water maintained at 25℃ for 2h. The animals were decapitated 5min, 6h, 24h and 48h after the cessation of stress. In all parts of the brain, the putrescine levels were significantly elevated 24h after stress application. The spermidine and spermine levels were unchanged or slightly reduced in the frontal cortex and hypothalamus 6h and 24h after stress application. In the plasma, there is no change in polyamine levels at any time intervals after stress application. In the case of restraint stress without water-immersion, putrescine level was increased only in the frontal cortex. Pretreatment with diazepam (5mg/kg, i. p.) reduced the stress-induced polyamine changes. These results indicate that the change of polyamine metabolism is linked to traumatic stress and its magnitude appears to be related to the intensity of the stressor.