中樞去抑制易化由外周炎癥引發(fā)大鼠痛敏的機制研究
發(fā)布時間：2018-07-29 08:05
【摘要】： 慢性痛是影響最廣泛的疾病之一。據(jù)估計,在發(fā)達國家中約有20%的成年人受到慢性痛的困擾。雖然對急性痛的診斷和治愈目前都很有效,對慢性痛的治療則遠遠未達到人們的期望,因此了解慢性痛過程中神經(jīng)系統(tǒng)是如何作用的就顯得尤為迫切。已有的研究表明在慢性痛過程中中樞神經(jīng)系統(tǒng)中參與痛覺通路的多個腦區(qū)的神經(jīng)元活動增加,突觸傳遞發(fā)生變化引起中樞敏化。中樞神經(jīng)系統(tǒng)痛覺通路的變化是由外周傷害性感受器的輸入增多引發(fā),這種變化又導(dǎo)致了參與痛覺信息傳遞的神經(jīng)元對外界刺激的反應(yīng)進一步增強,并且這種增強是一種長時程的變化。研究指出中樞敏化過程中,中樞神經(jīng)系統(tǒng)的突觸傳遞發(fā)生了變化。其中興奮性突觸傳遞發(fā)生了易化,而抑制性突觸傳遞則被抑制。這就提高了興奮性,使得神經(jīng)元在接受傷害性刺激時反應(yīng)增強或是閾下刺激時也會產(chǎn)生反應(yīng)。 成年動物的中樞神經(jīng)系統(tǒng)中,GABA能突觸傳遞是主要的快速抑制性突觸傳遞。GABA_A受體是一種氯離子通道,神經(jīng)元胞內(nèi)外氯離子濃度梯度決定了它的效能。對多種神經(jīng)疾病的研究表明神經(jīng)元上氯離子的轉(zhuǎn)運體KCC2功能受到神經(jīng)元活動的調(diào)節(jié),進而改變抑制性突觸傳遞的效能。此外,GABA的合成酶,GABA能的中間神經(jīng)元以及GABA_A受體也都受到突觸活動的調(diào)節(jié),并且在神經(jīng)疾病中它們的表達與功能也發(fā)生變化。雖然已有人證明在外周神經(jīng)損傷引起的慢性痛過程中也存在著抑制性突觸傳遞的降低(去抑制),然而對這種降低的機制研究還不夠深入。本研究中,我們利用外周炎癥引起的慢性痛成年大鼠模型,對抑制性系統(tǒng)在中樞痛覺通路的多個腦區(qū)的變化進行了研究,并探索了調(diào)節(jié)抑制性突觸傳遞的可能生理意義。 1.慢性炎癥痛大鼠脊髓背角KCC2的表達變化與其機制的研究 本研究中,我們發(fā)現(xiàn)在外周炎癥誘發(fā)的慢性痛過程中,脊髓背角淺層神經(jīng)元的KCC2表達明顯降低,并且這種降低呈現(xiàn)時間依賴關(guān)系,隨著慢性痛持續(xù)時間的延長,KCC2的表達持續(xù)降低。KCC2的表達降低起到了易化痛敏的作用。此外,單側(cè)的外周炎癥會引起雙側(cè)脊髓背角的KCC2表達降低。我們也證明慢性炎癥痛中KCC2的降低依賴于BDNF-TrkB受體信號通路的激活。我們的研究結(jié)果提示,在外周炎癥誘發(fā)的慢性痛過程中脊髓背角也會出現(xiàn)去抑制,KCC2降低易化痛敏的機制可能是減少神經(jīng)元胞內(nèi)外的氯離子梯度,降低了抑制性突觸傳遞的效能。而KCC表達降低的時間依賴性則提示其降低可能對慢性痛的維持貢獻更大。而KCC2的降低是由BDNF-TrkB受體信號通路的激活所導(dǎo)致的,這也說明KCC2的表達受到神經(jīng)元活動的調(diào)節(jié)。 2.前扣帶回皮層的去抑制易化了慢性痛中的痛敏的研究 本研究中,我們利用全細胞膜片鉗的方法首先檢測了外周炎癥誘發(fā)的慢性痛對前扣帶皮層Ⅱ,Ⅲ層神經(jīng)元上興奮性突觸傳遞的影響。我們發(fā)現(xiàn)慢性痛導(dǎo)致了這些神經(jīng)元的興奮性輸入增多。另一方面,這些神經(jīng)元接受的抑制性突觸傳遞則發(fā)生了顯著降低。我們進一步對抑制性突觸傳遞降低的機制進行了探索。通過對mIPSC進行非穩(wěn)態(tài)噪音分析,我們發(fā)現(xiàn)在突觸傳遞過程中被激活的GABA_A受體數(shù)量減少,同時通過配對刺激記錄IPSC,我們發(fā)現(xiàn)在慢性痛中抑制性突觸的突觸前釋放機制發(fā)生了變化但釋放概率沒有降低,這就提示我們觀察到的抑制性突觸傳遞的降低可能主要是由于突觸后受體減少造成的。通過檢測GABA_A受體的β2,3亞基在前扣帶回皮層的表達我們發(fā)現(xiàn)外周炎癥誘發(fā)的慢性痛降低了GABA_A受體在前扣帶回皮層的表達,KCC2的表達也降低。另一方面,負責(zé)合成GABA的谷氨酸脫羧酶的表達并沒有降低,GAD65的表達反而在慢性痛中上升。此外,外周炎癥誘發(fā)的慢性痛引起前扣帶皮層神經(jīng)元的輸出增加并且我們的結(jié)果提示這些神經(jīng)元對興奮性輸入的整合發(fā)生變化。行為學(xué)實驗則提示,慢性痛中增強前扣帶皮層抑制性突觸傳遞可以減緩?fù)疵簟Ｒ虼?本研究提示,前扣帶回皮層的抑制性突觸傳遞的降低易化了慢性痛中痛敏,這種降低是由于GABA_A受體和KCC2的表達降低引起的。而與此同時,前扣帶回皮層的抑制性系統(tǒng)也可能存在著穩(wěn)態(tài)調(diào)節(jié)機制試圖彌補受體表達降低導(dǎo)致的抑制性突觸傳遞的削弱。增高的興奮性與降低的抑制性輸入就導(dǎo)致了神經(jīng)元的輸出增加。 本工作的創(chuàng)新在于:1)第一次報道了外周炎癥誘發(fā)的慢性痛會導(dǎo)致KCC2的表達長時程下調(diào),并且這種下調(diào)依賴于BDNF-TrkB受體信號途徑的激活。這就提示了KCC2表達降低可能是對多種慢性痛的維持起重要作用。2)第一次報道了外周炎癥誘發(fā)的慢性痛會導(dǎo)致前扣帶回皮層抑制性突觸傳遞的降低,這種降低促進了了神經(jīng)元的輸出,易化了痛敏。并且我們也證明在慢性痛中前扣帶回皮層抑制性系統(tǒng)存在穩(wěn)態(tài)調(diào)節(jié)機制。
[Abstract]:Chronic pain is one of the most widely affected diseases. It is estimated that about 20% of adults in developed countries are suffering from chronic pain. Although the diagnosis and cure of acute pain are now very effective and the treatment of chronic pain is far from people's expectations, it is particularly important to know how the nervous system works in the process of chronic pain. The changes in the pain pathway of the central nervous system are caused by the increase in the input of the peripheral nociceptive receptor, which leads to the involvement of the pain in the central nervous system. The synaptic transmission in the central nervous system changes in the central sensitization process. In the central sensitization process, the synaptic transmission in the central nervous system is changed, and the inhibitory synaptic transmission is suppressed. This increases the excitement. Sex makes neurons respond more strongly when they receive nociceptive stimuli or react under subliminal stimuli.
In the central nervous system of adult animals, GABA synaptic transmission is the major fast inhibitory synaptic transmission, the.GABA_A receptor is a chloride channel, and the concentration gradient of the intracellular and external chlorine ion determines its effectiveness. A study of various neural diseases indicates that the function of the transporter KCC2 function of the neurons on the neuron is subjected to neuronal activity. In addition, GABA synthase, GABA intermediate neurons and GABA_A receptors are also regulated by synaptic activity, and their expression and function are also changed in neural diseases. Although it has been shown that there is also inhibition in the process of chronic pain caused by peripheral nerve injury. In this study, we studied the changes in the multiple brain regions of the central pain pathway and explored the possible physiological regulation of the inhibitory synaptic transmission in this study. Significance.
Expression and mechanism of KCC2 in spinal dorsal horn of 1. chronic inflammatory pain rats
In this study, we found that in the process of chronic pain induced by peripheral inflammation, the expression of KCC2 in the superficial neurons of the dorsal horn of the spinal cord decreased significantly, and the decrease presented a time dependence. With the prolonged duration of chronic pain, the expression of KCC2 continued to decrease and the expression of.KCC2 decreased to the role of susceptibility to pain sensitivity. Inflammation may cause a decrease in KCC2 expression in the dorsal horn of the spinal cord. We also demonstrate that the reduction of KCC2 in chronic inflammatory pain depends on the activation of the BDNF-TrkB receptor signaling pathway. Our results suggest that the dorsal horn of the spinal cord also appears depressing during the process of chronic inflammation induced by peripheral inflammation, and the mechanism for reducing the susceptibility to susceptibility to KCC2 may be the reduction of God. The inhibitory synaptic transmission is reduced by the intracellular and extracellular chloride gradient, and the time dependence of the decrease of KCC expression suggests that its reduction may contribute more to the maintenance of chronic pain. The reduction of KCC2 is caused by the activation of the BDNF-TrkB receptor signaling pathway, which also indicates that the expression of KCC2 is regulated by neuronal activity.
2. the inhibition of anterior cingulate cortex facilitates the study of pain sensitivity in chronic pain.
In this study, we used whole cell patch clamp techniques to first detect the effects of chronic pain induced by peripheral inflammation on excitatory synaptic transmission on the neurons in the anterior cingulate cortex II and III neurons. We found that chronic pain leads to increased excitatory input in these neurons. On the other hand, these neurons accept inhibitory synaptic transmission. We further explored the mechanism of the inhibition of inhibition of synaptic transmission. By analyzing the nonstationary noise of mIPSC, we found that the number of activated GABA_A receptors in the synaptic transmission was reduced and the IPSC was recorded by paired stimuli, and we found the presynaptic release of the inhibitory synapse in chronic pain. The release mechanism changes but the release probability does not decrease, which suggests that the decrease of the inhibitory synaptic transmission is probably due to the reduction of postsynaptic receptors. By detecting the expression of the GABA_A receptor's beta 2,3 subunit in the anterior cingulate cortex, we found that the chronic pain induced by peripheral inflammation reduces the GABA_A receptor in the CINgle. The expression of KCC2 in the anterior cingulate cortex was also reduced. On the other hand, the expression of glutamic acid decarboxylase, which was responsible for the synthesis of GABA, did not decrease, and the expression of GAD65 increased in chronic pain. In addition, the chronic pain induced by peripheral inflammation caused the output of the neurons in the anterior cingulate cortex and our results suggest that these neurons are on the rise. This study suggests that the reduction of inhibitory synaptic transmission in the anterior cingulate cortex facilitates the reduction of chronic pain sensitivity, which is caused by a decrease in the expression of GABA_A receptor and KCC2. At the same time, the inhibitory system of the cingulate cortex may also have homeostasis mechanisms that try to compensate for the weakening of the inhibitory synaptic transmission resulting from the decrease in the receptor expression. Increased excitability and reduced inhibitory inputs lead to an increase in the output of neurons.
The innovations in this work are as follows: 1) the first report of chronic pain induced by peripheral inflammation leads to a long time downregulation of the expression of KCC2, and this downregulation depends on the activation of the BDNF-TrkB receptor signaling pathway. This suggests that the decrease of KCC2 expression may be an important role in the maintenance of multiple chronic pain.2) the first report of peripheral inflammation Chronic pain leads to a decrease in the inhibitory synaptic transmission of the anterior cingulate cortex, which promotes the output of neurons and facilitates pain sensitivity. And we have also demonstrated that there is a steady regulation mechanism in the cingulate cortex suppressor system in chronic pain.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2008
【分類號】：R363
本文編號：2152044
[Abstract]:Chronic pain is one of the most widely affected diseases. It is estimated that about 20% of adults in developed countries are suffering from chronic pain. Although the diagnosis and cure of acute pain are now very effective and the treatment of chronic pain is far from people's expectations, it is particularly important to know how the nervous system works in the process of chronic pain. The changes in the pain pathway of the central nervous system are caused by the increase in the input of the peripheral nociceptive receptor, which leads to the involvement of the pain in the central nervous system. The synaptic transmission in the central nervous system changes in the central sensitization process. In the central sensitization process, the synaptic transmission in the central nervous system is changed, and the inhibitory synaptic transmission is suppressed. This increases the excitement. Sex makes neurons respond more strongly when they receive nociceptive stimuli or react under subliminal stimuli.
In the central nervous system of adult animals, GABA synaptic transmission is the major fast inhibitory synaptic transmission, the.GABA_A receptor is a chloride channel, and the concentration gradient of the intracellular and external chlorine ion determines its effectiveness. A study of various neural diseases indicates that the function of the transporter KCC2 function of the neurons on the neuron is subjected to neuronal activity. In addition, GABA synthase, GABA intermediate neurons and GABA_A receptors are also regulated by synaptic activity, and their expression and function are also changed in neural diseases. Although it has been shown that there is also inhibition in the process of chronic pain caused by peripheral nerve injury. In this study, we studied the changes in the multiple brain regions of the central pain pathway and explored the possible physiological regulation of the inhibitory synaptic transmission in this study. Significance.
Expression and mechanism of KCC2 in spinal dorsal horn of 1. chronic inflammatory pain rats
In this study, we found that in the process of chronic pain induced by peripheral inflammation, the expression of KCC2 in the superficial neurons of the dorsal horn of the spinal cord decreased significantly, and the decrease presented a time dependence. With the prolonged duration of chronic pain, the expression of KCC2 continued to decrease and the expression of.KCC2 decreased to the role of susceptibility to pain sensitivity. Inflammation may cause a decrease in KCC2 expression in the dorsal horn of the spinal cord. We also demonstrate that the reduction of KCC2 in chronic inflammatory pain depends on the activation of the BDNF-TrkB receptor signaling pathway. Our results suggest that the dorsal horn of the spinal cord also appears depressing during the process of chronic inflammation induced by peripheral inflammation, and the mechanism for reducing the susceptibility to susceptibility to KCC2 may be the reduction of God. The inhibitory synaptic transmission is reduced by the intracellular and extracellular chloride gradient, and the time dependence of the decrease of KCC expression suggests that its reduction may contribute more to the maintenance of chronic pain. The reduction of KCC2 is caused by the activation of the BDNF-TrkB receptor signaling pathway, which also indicates that the expression of KCC2 is regulated by neuronal activity.
2. the inhibition of anterior cingulate cortex facilitates the study of pain sensitivity in chronic pain.
In this study, we used whole cell patch clamp techniques to first detect the effects of chronic pain induced by peripheral inflammation on excitatory synaptic transmission on the neurons in the anterior cingulate cortex II and III neurons. We found that chronic pain leads to increased excitatory input in these neurons. On the other hand, these neurons accept inhibitory synaptic transmission. We further explored the mechanism of the inhibition of inhibition of synaptic transmission. By analyzing the nonstationary noise of mIPSC, we found that the number of activated GABA_A receptors in the synaptic transmission was reduced and the IPSC was recorded by paired stimuli, and we found the presynaptic release of the inhibitory synapse in chronic pain. The release mechanism changes but the release probability does not decrease, which suggests that the decrease of the inhibitory synaptic transmission is probably due to the reduction of postsynaptic receptors. By detecting the expression of the GABA_A receptor's beta 2,3 subunit in the anterior cingulate cortex, we found that the chronic pain induced by peripheral inflammation reduces the GABA_A receptor in the CINgle. The expression of KCC2 in the anterior cingulate cortex was also reduced. On the other hand, the expression of glutamic acid decarboxylase, which was responsible for the synthesis of GABA, did not decrease, and the expression of GAD65 increased in chronic pain. In addition, the chronic pain induced by peripheral inflammation caused the output of the neurons in the anterior cingulate cortex and our results suggest that these neurons are on the rise. This study suggests that the reduction of inhibitory synaptic transmission in the anterior cingulate cortex facilitates the reduction of chronic pain sensitivity, which is caused by a decrease in the expression of GABA_A receptor and KCC2. At the same time, the inhibitory system of the cingulate cortex may also have homeostasis mechanisms that try to compensate for the weakening of the inhibitory synaptic transmission resulting from the decrease in the receptor expression. Increased excitability and reduced inhibitory inputs lead to an increase in the output of neurons.
The innovations in this work are as follows: 1) the first report of chronic pain induced by peripheral inflammation leads to a long time downregulation of the expression of KCC2, and this downregulation depends on the activation of the BDNF-TrkB receptor signaling pathway. This suggests that the decrease of KCC2 expression may be an important role in the maintenance of multiple chronic pain.2) the first report of peripheral inflammation Chronic pain leads to a decrease in the inhibitory synaptic transmission of the anterior cingulate cortex, which promotes the output of neurons and facilitates pain sensitivity. And we have also demonstrated that there is a steady regulation mechanism in the cingulate cortex suppressor system in chronic pain.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2008
【分類號】：R363
【引證文獻】
相關(guān)期刊論文 前1條
1 付立波;房麗;王學(xué)斌;李聰;楊燕平;欒添;沈勇;韓國軍;趙晶華;王穎;;五味子對炎癥痛大鼠的鎮(zhèn)痛作用[J];黑龍江畜牧獸醫(yī);2014年12期
，本文編號：2152044
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