大鼠初级躯体感觉皮层神经元对痒觉刺激的反应特性

发布时间：2018-03-04 02:30

本文选题：初级躯体感觉皮层　切入点：痒觉　出处：《华东师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：痒是一种引起抓挠欲望的不愉快的感觉。目前,关于痒觉中枢机制的研究多采用脑功能成像的方法,这些研究虽然能让我们看到脑内有哪些脑区参与了痒觉信息的处理,但不能帮助我们了解这些脑区是如何对痒觉信息进行处理的。脑成像研究对于初级躯体感觉皮层(Primary somatosensory cortex,SI)是否参与了痒觉信息的处理还存在争论,本论文首次采用在体单细胞记录的方法,从微观层面上研究初级躯体感觉皮层是否参与痒觉信息的处理。本实验以wistar大鼠(10只,雄性,300-400克体重)作为实验动物,手术将电极阵列埋置在双侧的SI,动物恢复后,在戊巴比妥钠麻醉状态下,给予三种致痒剂(组胺、氯喹和五羟色胺)刺激,记录初级躯体感觉皮层神经元对不同致痒剂的反应,并记录了这些神经元对机械刺激和痛刺激(激光和辣椒素)的反应,以鉴定这些神经元的性质。对这些神经元的放电信号进行离线分析,观察并比较SI神经元对不同刺激的反应模式。本研究记录到了 51个SI神经元,其中65%可以被组胺激活,而对五羟色胺和氯喹有响应的神经元比例低于组胺响应神经元的比例(分别为39%和29%);组胺和氯喹、五羟色胺激活的神经元群体具有很大的重合;从不同致痒剂的反应持续时间上来看,五羟色胺引起的反应持续时间最长,其次是组胺和氯喹;大部分(92%)致痒剂响应神经元是广动力范围神经元,能被机械刺激或痛觉刺激所激活。综上所述,我们的结果显示在SI内存在对致痒剂响应的神经元,并且绝大部分为多模态神经元,非组胺依赖型致痒剂激活的可能是组胺响应神经元中的一个亚群,暗示在啮齿类动物的SI内可能不存在分离的通路来处理组胺依赖和非组胺依赖的痒觉信息。本研究为SI参与痒觉信息的处理提供了直接证据,将大大推进我们对痒觉中枢机制的理解。
[Abstract]:Itching is an unpleasant feeling that causes scratching. At present, many studies on the mechanism of itch center use brain function imaging, although these studies can show us which brain regions are involved in the processing of itch information. But it doesn't help us understand how these brain regions process itching information. Brain imaging studies have debated whether primary somatosensory cortexSIs are involved in the processing of itch information. In this paper, we used the method of single cell recording in vivo for the first time to study whether the primary somatosensory cortex is involved in the processing of itch information at the microcosmic level. In this experiment, 10 wistar rats, male rats, 300-400g body weight) were used as experimental animals. The electrodes were implanted in bilateral SIs. After recovery, the animals were stimulated with three kinds of itching agents (histamine, chloroquine and serotonin) under pentobarbital sodium anesthesia. The responses of primary somatosensory cortical neurons to different itching agents were recorded. The responses of these neurons to mechanical and pain stimuli (laser and capsaicin) were recorded to identify the properties of these neurons. The response patterns of SI neurons to different stimuli were observed and compared. 51 SI neurons were recorded in this study, of which 65% could be activated by histamine. The proportion of neurons responding to serotonin and chloroquine was lower than that of histamine responsive neurons (39% and 29, respectively). According to the reaction duration of different itching agents, serotonin caused the longest reaction duration, followed by histamine and chloroquine; Which can be activated by mechanical or pain stimuli. In summary, our results show that there are neurons in SI that respond to itching agents, and most of them are multimodal neurons. Non-histamine-dependent itching agents may activate a subgroup of histamine-responsive neurons. It is suggested that there may not be separate pathways in rodent SI to process histamine-dependent and non-histamine-dependent itch information. This study provides direct evidence that SI is involved in the processing of itching information. This will greatly advance our understanding of the central mechanism of itching.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：B842

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