缰核对大鼠自发活动昼夜节律的影响及可能机制
发布时间：2018-10-19 20:29
【摘要】： 昼夜节律贯穿于所有生物体生命活动的始终。下丘脑视交叉上核(SCN)作为哺乳动物昼夜节律的主起搏器(生物钟)已经得到许多实验的证明,并一直成为许多学者关注的热点。而缰核是目前少有的已被证实自身可呈现出与SCN相似节律性振荡的脑内核团,且其与SCN之间还存在着密切的形态学与功能学上的联系。另外,缰核与昼夜节律系统中另一重要结构——松果体之间也存在着独有的解剖学关系及密切的功能联系。因此,缰核很可能在昼夜节律系统的调节中发挥重要的作用。 本研究首先通过实验观察在持续黑暗(DD)及光暗周期(LD)条件下损毁缰核对大鼠自发活动昼夜节律的影响,随后运用高效液相色谱(HPLC)荧光法检测不同条件下缰核损毁大鼠纹状体内的多巴胺(DA)及5-羟色胺(5-HT)含量变化,试图揭示缰核损毁对大鼠跑轮活动影响的作用机制。同时,本研究还应用HPLC检测了缰核损毁大鼠松果体内褪黑素(Mel)的含量变化、应用透射电镜技术观察了缰核损毁对松果体细胞超微结构的影响及运用电生理学技术研究离体脑片缰核神经元对不同剂量Mel的反应,以考察缰核在松果体和Mel所参与昼夜节律调节过程中的作用。 结果显示,缰核损毁大鼠在DD条件下仍表现为近似24h的自由运行周期不变,但自发活动在自由运转周期内的分布却发生了显著性变化。在LD条件下,缰核损毁可明显加快大鼠对光照延后8 h再导引作用的反应速度,但不改变其对光照前移8 h再导引作用的反应。在DD条件下,缰核损毁大鼠纹状体内DA含量变化与自发跑轮活动在自由运转周期内分布的变化呈现反相关系:即在主观夜晚,DA含量增加,跑轮活动所占的比例降低;在主观白天,DA含量减少,而跑轮活动所占的比例明显增高。在LD条件下,缰核损毁3周时纹状体内的DA含量在光时相及暗时相都表现为增加。而纹状体内的5-HT,无论是LD还是DD条件下,损毁3周时都只表现为暗时相/主观夜晚时含量的增加。但LD条件下缰核损毁8周时纹状体内DA及5-HT的含量都表现为ZT4点的明显降低。结果还显示,缰核损毁后DD条件下松果体内Mel含量无明显变化。而在LD条件下松果体内的Mel含量及松果体的重量在暗时相均明显降低;同时,损毁大鼠的松果体细胞超微结构也发生了显著性的变化。此外,约有70%的缰核神经元在离体给予Mel后可发生明显性的放电变化,且不同浓度的Mel所引起的放电变化反应类型有明显的不同。但是,缰核的不同亚核对10-7 mol/L Mel的反应无明显的区域性差异。结果表明:缰核参与SCN产生的内源性节律的调节过程,其机制可能有脑内DA及5-HT系统的参与;同时缰核也可通过与松果体之间的相互作用关系进而实现其对昼夜节律的调节,一方面缰核可通过对松果体的调控影响其内Mel的合成和分泌,另一方面,它也是Mel在脑内作用的重要靶点。
[Abstract]:The circadian rhythm runs through the life of all living organisms. As the main pacemaker (circadian clock) of mammalian circadian rhythm, the supraoptic nucleus of hypothalamus (SCN) has been proved by many experiments and has been a hot topic for many researchers. Habenular nucleus is one of the few nuclei which has been proved to exhibit rhythmic oscillations similar to that of SCN, and there is a close relationship between habenular nucleus and SCN in morphology and function. In addition, there is a unique anatomical relationship and close functional relationship between the habenular nucleus and the pineal gland, another important structure in the circadian rhythm system. Therefore, habenular nucleus may play an important role in the regulation of circadian rhythm system. In this study, the effects of continuous dark (DD) and light-dark period (LD) on the circadian rhythm of spontaneous activity of habenular nucleus in rats were studied. Then the changes of dopamine (DA) and 5-hydroxytryptamine (5-HT) in the striatum of rats with habenular nucleus lesion under different conditions were detected by high performance liquid chromatography (HPLC) fluorescence method in order to elucidate the mechanism of the effect of habenular nucleus damage on rat wheel running activity. At the same time, HPLC was used to detect the changes of melatonin (Mel) in the pineal gland of rats with habenular nucleus lesion. The effects of habenular nucleus lesion on ultrastructure of pineal cells were observed by transmission electron microscopy (TEM) and electrophysiological techniques were used to study the response of habenula neurons to different doses of Mel in vitro. To investigate the role of habenular nucleus in the regulation of circadian rhythm in the pineal gland and Mel. The results showed that the free cycle of habenular nucleus lesion remained unchanged in approximately 24 hours under DD, but the distribution of spontaneous activity in the free cycle changed significantly. Under the condition of LD, the damage of habenular nucleus could significantly accelerate the response of rats to light delayed 8 h reguidance, but it did not change its response to light forward 8 h re guidance. Under the condition of DD, the change of DA content in striatum of rats with habenular nucleus lesion was inversely related to the distribution of spontaneous wheel running activity in the free running cycle: in subjective night, the content of DA increased and the proportion of wheel running decreased. During the subjective day, the content of DA decreased and the proportion of wheel running increased significantly. Under the condition of LD, the content of DA in striatum was increased in both light phase and dark phase after 3 weeks of habenular nucleus lesion. However, 5-HT in striatum, whether under LD or DD, showed only the increase of dark phase / subjective night time at 3 weeks after lesion. However, the contents of DA and 5-HT in striatum were significantly decreased at 8 weeks after habenular nucleus lesion under LD condition. The results also showed that there was no significant change of Mel content in pineal body after habenular nucleus lesion under DD. The content of Mel in pineal gland and the weight of pineal gland decreased significantly in dark phase under LD condition, and the ultrastructure of pineal cells in damaged rats also changed significantly at the same time. In addition, about 70% of habenula neurons had obvious changes in discharge after in vitro administration of Mel, and the types of response to different concentrations of Mel were significantly different. However, there were no significant regional differences in response to 10-7 mol/L Mel in different subnuclei of habenular nucleus. The results showed that the habenular nucleus was involved in the regulation of endogenous rhythm produced by SCN, and the mechanism of habenular nucleus might be involved in the DA and 5-HT system in the brain, and the habenular nucleus could also regulate the circadian rhythm through the interaction with pineal gland. On the one hand, the habenular nucleus can affect the synthesis and secretion of Mel through the regulation of pineal body. On the other hand, it is also an important target of Mel in brain.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：R338
本文编号：2282276
[Abstract]:The circadian rhythm runs through the life of all living organisms. As the main pacemaker (circadian clock) of mammalian circadian rhythm, the supraoptic nucleus of hypothalamus (SCN) has been proved by many experiments and has been a hot topic for many researchers. Habenular nucleus is one of the few nuclei which has been proved to exhibit rhythmic oscillations similar to that of SCN, and there is a close relationship between habenular nucleus and SCN in morphology and function. In addition, there is a unique anatomical relationship and close functional relationship between the habenular nucleus and the pineal gland, another important structure in the circadian rhythm system. Therefore, habenular nucleus may play an important role in the regulation of circadian rhythm system. In this study, the effects of continuous dark (DD) and light-dark period (LD) on the circadian rhythm of spontaneous activity of habenular nucleus in rats were studied. Then the changes of dopamine (DA) and 5-hydroxytryptamine (5-HT) in the striatum of rats with habenular nucleus lesion under different conditions were detected by high performance liquid chromatography (HPLC) fluorescence method in order to elucidate the mechanism of the effect of habenular nucleus damage on rat wheel running activity. At the same time, HPLC was used to detect the changes of melatonin (Mel) in the pineal gland of rats with habenular nucleus lesion. The effects of habenular nucleus lesion on ultrastructure of pineal cells were observed by transmission electron microscopy (TEM) and electrophysiological techniques were used to study the response of habenula neurons to different doses of Mel in vitro. To investigate the role of habenular nucleus in the regulation of circadian rhythm in the pineal gland and Mel. The results showed that the free cycle of habenular nucleus lesion remained unchanged in approximately 24 hours under DD, but the distribution of spontaneous activity in the free cycle changed significantly. Under the condition of LD, the damage of habenular nucleus could significantly accelerate the response of rats to light delayed 8 h reguidance, but it did not change its response to light forward 8 h re guidance. Under the condition of DD, the change of DA content in striatum of rats with habenular nucleus lesion was inversely related to the distribution of spontaneous wheel running activity in the free running cycle: in subjective night, the content of DA increased and the proportion of wheel running decreased. During the subjective day, the content of DA decreased and the proportion of wheel running increased significantly. Under the condition of LD, the content of DA in striatum was increased in both light phase and dark phase after 3 weeks of habenular nucleus lesion. However, 5-HT in striatum, whether under LD or DD, showed only the increase of dark phase / subjective night time at 3 weeks after lesion. However, the contents of DA and 5-HT in striatum were significantly decreased at 8 weeks after habenular nucleus lesion under LD condition. The results also showed that there was no significant change of Mel content in pineal body after habenular nucleus lesion under DD. The content of Mel in pineal gland and the weight of pineal gland decreased significantly in dark phase under LD condition, and the ultrastructure of pineal cells in damaged rats also changed significantly at the same time. In addition, about 70% of habenula neurons had obvious changes in discharge after in vitro administration of Mel, and the types of response to different concentrations of Mel were significantly different. However, there were no significant regional differences in response to 10-7 mol/L Mel in different subnuclei of habenular nucleus. The results showed that the habenular nucleus was involved in the regulation of endogenous rhythm produced by SCN, and the mechanism of habenular nucleus might be involved in the DA and 5-HT system in the brain, and the habenular nucleus could also regulate the circadian rhythm through the interaction with pineal gland. On the one hand, the habenular nucleus can affect the synthesis and secretion of Mel through the regulation of pineal body. On the other hand, it is also an important target of Mel in brain.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：R338
【引证文献】
相关硕士学位论文 前1条
1 褚峰;温度对基于光授时信号途径的家蚕BmN细胞生物钟基因表达的影响[D];苏州大学;2014年
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