SKF83959和IGF2对小鼠恐惧记忆消散和抑郁样行为的作用及机制

发布时间：2018-06-03 16:06

本文选题：杏仁核 + 恐惧记忆消散　；参考：《华中科技大学》2015年博士论文

【摘要】：第一部分SKF83959对小鼠恐惧记忆消散的作用及机制目的：SKF83959可被视为Gq蛋白偶联多巴胺受体的一种激动剂,其已被证明具有抗抑郁、帮助改善帕金森病(Parkinson's disease,PD)动物模型的PD症状等多种有益作用。目前为止,尚不清楚SKF83959是否对动物的恐惧记忆消散会产生一定的影响。有鉴于此,我们在此研究了SKF83959对恐惧记忆消散的作用。方法：采用fear conditioning行为学实验方法研究SKF83959对小鼠恐惧记忆消散的影响；应用旷场实验方法研究SKF83959对小鼠自发活动及基础焦虑水平的影响;运用脑区套管埋置、脑区注射给药方法结合fear conditioning行为学实验方法研究SKF83959促进小鼠恐惧记忆消散作用的发挥是否有赖于杏仁核脑区磷脂酶C/肌醇三磷酸/钙离子(phospholipase C/inositol triphosphate/Ca2+, PLC/IP3/Ca2+)信号通路的激活。结果：(1)Fear conditioning开始之前SKF83959腹腔注射给药(每天1次,1mg/kg/day,为期7天)显著促进小鼠恐惧记忆的消散,对恐惧记忆的自发性恢复(spontaneous recovery)、续新(renewal)及复燃(reinstatement)等现象亦具有显著的抑制作用：在记忆的自发性恢复实验中,SKF83959可使小鼠的僵直率由60.9±5.1%降至44.2±4.4%(n=7-8/group,p0.05vs vehicle):在记忆的续新实验中,SKF83959可使小鼠的僵直率由78.4±3.2%降至67.5±3.2%(n=8-10/group,p0.05vs vehicle)；在记忆的复燃实验中,SKF83959可使小鼠的僵直率由95.2±0.7%降至78.3±2.3%(n=10-13/group,p0.01vs vehicle).同样地,feaur conditioning结束之后SKF83959腹腔注射给药(每天1次,1mg/kg/day,为期7天)亦具有上述作用：在记忆的续新实验中,SKF83959可使小鼠的僵直率由52.0±7.0%降至28.9±5.4%(n=7/group,p0.05vs vehicle)；在记忆的复燃实验中,SKF83959可使小鼠的僵直率由90.9±3.1%降至71.0±7.1%(n=11/group,p0.05vs vehicle).(2)SKF83959腹腔注射给药(每天1次,1mg/kg/day,为期7天)并不影响小鼠的自发活动及基础焦虑水平。(3)SKF83959通过激活杏仁核脑区的PLC/IP3/Ca2+信号通路促进小鼠恐惧记忆的消散。结论：SKF83959具有显著的恐惧记忆消散促进作用,这一作用的发挥有赖于动物杏仁核脑区PLC/IP3/Ca2+信号通路的激活。第二部分IGF2对慢性社会挫败应激所致小鼠抑郁样行为的作用目的：胰岛素样生长因子2(insulin-like growth factor2,IGF2)是胰岛素样多肽家族(insulin-like peptide family)的重要一员。尽管最近刚有研究指出IGF2具有显著的抗抑郁作用,不过,对于中枢神经系统内由IGF2所介导的信号通路在动物抑郁样行为的产生过程中所起的作用仍有待做进一步的挖掘。有鉴于此,我们开展了相关研究,力争使我们对中枢神经系统内由IGF2所介导的信号通路对动物抑郁样行为的调控作用有一个更好的认识。方法：建立小鼠慢性社会挫败应激(chronic social defeat stress,CSDS)抑郁模型；利用western blotting实验方法对慢性社会挫败应激抑郁模型小鼠海马脑区IGF2的蛋白表达水平进行检测;在应用shRNA介导的基因干扰技术对小鼠海马脑区的IGF2基因进行沉默(knockdown)的基础上,应用强迫游泳行为学实验方法及阈下社会挫败应激模式对小鼠在抑郁样行为及其对不良应激的易感性方面所发生的改变进行测定；应用脑区套管埋置及脑区注射给药技术研究海马脑区给予外源性IGF2对小鼠强迫游泳行为及CSDS所致小鼠抑郁样行为的影响。结果：(1)接受过CSDS处理的小鼠其海马脑区IGF2的蛋白表达水平与其所表现出的抑郁样行为的严重程度密切相关。具有越严重的抑郁样行为的小鼠其海马脑区IGF2的蛋白表达水平越低。(2)对小鼠海马脑区的IGF2基因进行沉默可诱发小鼠抑郁样行为的产生,这一作用具体表现在：海马脑区IGF2基因沉默可使小鼠的强迫游泳不动时间由131±26s增至222±34s(n=13-15/group,p0.05vs control).与此同时,海马脑区IGF2基因沉默亦可使小鼠对阈下社会挫败应激的易感性得到显著增加。在社会接触行为学实验中,海马脑区IGF2基因沉默可使小鼠在target阶段的社会接触时间由51.4±8.0s减少为29.5±6.7s(n=11-13/group,p0.05vs control)；在糖水偏好实验中,海马脑区IGF2基因沉默可使小鼠的糖水偏好水平由89.8±2.6%降至71.3±6.4%(n=11-13/group,p0.05vs control).(3)小鼠海马脑区给予IGF2具有抗抑郁作用,具体表现在：海马脑区急性给予IGF2(2.5ng/side)可显著减少小鼠的强迫游泳不动时间,具体而言,IGF2可使动物的强迫游泳不动时间由94±11s减少为49±12s(PBS:n=21；IGF2(2.5ng/side):n=14:p0.05vs PBS)；海马脑区多次重复给予IGF2(250ng/side,为期7天)可逆转CSDS所致小鼠抑郁样行为的产生。在社会接触行为学实验中,IGF2可使CSDS易感鼠在target阶段的社会接触时间由14.6±4.1s增至38.8±5.4s(CSDS susceptible-PBS:n=10；CSDS susceptible-IGF2(250ng/side): n=10；p0.05vs CSDS susceptible-PBS)；在糖水偏好实验中,IGF2可使CSDS易感鼠的糖水偏好水平由64.2±3.2%增至85.7±3.0%(CSDS susceptible-PBS:n=9；CSDS susceptible-IGF2(250ng/side):n:9；p0.01vs CSDS susceptible-PBS)。IGF2抗抑郁作用的发挥有赖于海马脑区的IGF2受体而非IGF1受体的激活。结论：小鼠海马脑区由IGF2/IGF2受体所介导的信号通路在小鼠抑郁样行为的产生过程中扮演重要角色。下调海马脑区IGF2的表达水平可增加小鼠对应激的易感性,相反,小鼠海马脑区给予IGF2则可通过激活海马脑区内的IGF2受体而非IGF1受体产生抗抑郁作用。
[Abstract]:Part one: the effect and mechanism of SKF83959 on mice's fear memory dissipation.
Objective: SKF83959 can be considered as an agonist of the Gq protein coupled dopamine receptor, which has been proved to be antidepressant and helps to improve the PD symptoms of Parkinson's disease (Parkinson's disease, PD) animal models. So far, it is not clear whether SKF83959 will have a certain effect on the dissipation of fear memory in animals. In view of this, we studied the effect of SKF83959 on fear memory dissipation.
Methods: the effect of SKF83959 on the dissipation of fear memory in mice was studied by fear conditioning behavior test, and the effect of SKF83959 on spontaneous activity and basic anxiety level of mice was studied by using open field experiment. The method of using brain area cannula, brain area injection and fear conditioning behavior study method to study SKF8 3959 whether to promote the effect of fear memory dissipation in mice depends on the activation of the signal pathway of the phospholipase C/ inositol three phosphate / calcium ion (phospholipase C/inositol triphosphate/Ca2+, PLC/IP3/Ca2+) in the amygdala brain region.
Results: (1) SKF83959 intraperitoneal injection of SKF83959 before the beginning of conditioning (1 times a day, 1mg/kg/day for 7 days) significantly promoted the dissipation of fear memory in mice, and also had a significant inhibitory effect on the spontaneous recovery of fear memory (spontaneous recovery), continued new (renewal) and reignition (reinstatement) and other phenomena: the spontaneity of memory. In the recovery experiment, SKF83959 can reduce the rigidity of mice from 60.9 + 5.1% to 44.2 + 4.4% (n=7-8/group, p0.05vs vehicle). In the new experiment of memory, SKF83959 can reduce the rigidity of mice from 78.4 + 3.2% to 67.5 + 3.2% (n=8-10/group, p0.05vs vehicle). In memory reburning experiment, SKF83959 can make the rigidity of mice by 95.2 + 0 .7% was reduced to 78.3 + 2.3% (n=10-13/group, p0.01vs vehicle). Similarly, SKF83959 intraperitoneal injection after feaur conditioning (1 times a day, 1mg/kg/day, 7 days) also had the above effect: in the new experiment of memory, SKF83959 could reduce the rigidity of mice from 52 + 7% to 28.9 + 5.4% (n=7/group, p0.05vs vehicle); In the reburning experiment of memory, SKF83959 can reduce the rigidity of mice from 90.9 + 3.1% to 71 + 7.1% (n=11/group, p0.05vs vehicle). (2) SKF83959 intraperitoneal injection (1 times a day, 1mg/kg/day, for 7 days) does not affect the spontaneous activity and basic anxiety level of mice. (3) SKF83959 through the activation of PLC/IP3/Ca2+ signaling pathway in the brain region of the amygdala. Promote the dissipation of fear memory in mice.
Conclusion: SKF83959 plays a significant role in promoting fear memory dissipation, which depends on activation of PLC/IP3/Ca2+ signaling pathway in amygdala brain region.
The second part is the effect of IGF2 on depressive behavior of mice induced by chronic social frustration.
Objective: insulin like growth factor 2 (insulin-like growth FACTOR2, IGF2) is an important member of the insulin like polypeptide family (insulin-like peptide family). Although recent studies have pointed out that IGF2 has a significant antidepressant effect, the signal pathway mediated by IGF2 in the central nervous system is depressive behavior in animals. The role of the production process remains to be further explored. In the light of this, we have carried out a study to make a better understanding of the role of IGF2 mediated signaling pathways in the regulation of animal depressive behavior in the central nervous system.
Methods: the chronic social defeat stress (CSDS) depression model of mice was established, and the protein expression level of IGF2 in the hippocampus of the chronic social frustration stress depression model mice was detected by Western blotting test, and the IGF2 gene of the hippocampus brain region of mice was applied by the shRNA mediated gene interference technique. On the basis of silence (knockdown), the experimental method of forced swimming behavior and the model of subthreshold social frustration stress were used to determine the changes in the behavior of depressive like and the susceptibility to adverse stress in mice. The application of brain area cannula embedding and brain region injection to study the hippocampus of the hippocampus was given to exogenous IGF2. Forced swimming behavior and CSDS induced depressive behavior in mice.
Results: (1) the protein expression level of IGF2 in the hippocampus of mice treated with CSDS was closely related to the severity of the depressive behavior. The lower the protein expression level of IGF2 in the hippocampus of the mice with the more severe depressive behavior was lower. (2) the silence of the IGF2 gene in the hippocampus of the mice could induce mice. The effect of depressive behavior is manifested in the following: IGF2 gene silencing in the hippocampus can increase the time of forced swimming in mice from 131 + 26S to 222 + 34S (n=13-15/group, p0.05vs control). At the same time, the IGF2 gene silencing in the hippocampus can also increase the susceptibility of mice to subthreshold social frustration stress. In the contact behavior experiment, the IGF2 gene silencing in the hippocampus could reduce the social contact time of the mice from 51.4 + 8.0s to 29.5 + 6.7s (n=11-13/group, p0.05vs control) in the target stage. In the sugar water preference experiment, the silencing of IGF2 gene in the hippocampus could reduce the sugar water preference level from 89.8 + 2.6% to 71.3 + 6.4% (n=11-13/group) in the hippocampus. P0.05vs control) (3) (3) the hippocampal brain area of the mice has antidepressant effect, which is manifested in the acute administration of IGF2 (2.5ng/side) in the hippocampus of the hippocampus, which can significantly reduce the time of forced swimming in mice. Specifically, IGF2 can reduce the time of forced swimming of animals from 94 + 11S to 49 + 12s (PBS:n=21; IGF2 (2.5ng/side)): n=14:p0.05 Vs PBS); IGF2 (250ng/side, 7 days) can reverse the production of depressive behavior in mice caused by CSDS in the hippocampus. In social contact behavior experiments, IGF2 can increase the social contact time of CSDS susceptible mice from 14.6 + 4.1s to 38.8 + 5.4s (CSDS susceptible-PBS:n=10). E: n=10; p0.05vs CSDS susceptible-PBS). In the sugar water preference experiment, IGF2 can increase the sugar water preference of CSDS susceptible mice from 64.2 + 3.2% to 85.7 + 3% (CSDS susceptible-PBS:n=9; CSDS susceptible-IGF2 (250ng/side)). The activation of the body is not the IGF1 receptor.
Conclusion: the signal pathway mediated by IGF2/IGF2 receptor in the hippocampus of mice plays an important role in the production of depressive behavior in mice. Down regulation of the expression level of IGF2 in the hippocampus can increase the susceptibility to stress in mice. On the contrary, the IGF2 in the hippocampus of the mice can be activated by activating the IGF2 receptor in the hippocampal brain instead of IGF1. The body produces antidepressant effect.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R749.5

【相似文献】