本文選題：疼痛 + 電壓門(mén)控鈉通道　； 參考：《上海大學(xué)》2015年博士論文

【摘要】：Bm K I,一個(gè)特異性電壓門(mén)控鈉通道位點(diǎn)3調(diào)制劑,已被驗(yàn)證能夠誘導(dǎo)大鼠傷害性感受行為。Nav1.8在外周炎癥痛以及神經(jīng)痛發(fā)生、發(fā)展和維持過(guò)程中的參與角色日益受到研究者關(guān)注。那么,Nav1.8是否/又如何參與Bm K I誘導(dǎo)的疼痛發(fā)生、發(fā)展以及維持?對(duì)此,本文采用動(dòng)物行為學(xué)及電生理學(xué)等手段,研究了Bm K I誘導(dǎo)大鼠疼痛模型中Nav1.8參與調(diào)控外周信號(hào)的細(xì)胞與分子機(jī)制。1.本研究發(fā)現(xiàn),經(jīng)Bm K I足底注射方式,兩小時(shí)后的電生理記錄發(fā)現(xiàn),急性分離的大鼠DRG神經(jīng)元中Nav1.8的電流密度顯著上升,同時(shí),其穩(wěn)態(tài)激活和穩(wěn)態(tài)失活曲線(xiàn)均向超極化方向偏移。鞘內(nèi)和足底預(yù)處理A-803467(Nav1.8選擇性阻斷劑),顯著地降低了大鼠自發(fā)痛和機(jī)械痛敏,但對(duì)熱痛敏沒(méi)有影響。結(jié)果清晰地提示,Bm K I誘導(dǎo)大鼠疼痛模型中,1)Nav1.8扮演了“首擋其沖”的應(yīng)激者,即在2小時(shí)短時(shí)程內(nèi)的應(yīng)激反應(yīng)觸發(fā)了外周傷害性感受神經(jīng)元的快速激活;2)Nav1.8是自發(fā)痛和機(jī)械痛的主要參與貢獻(xiàn)者,即Nav1.8表達(dá)量的應(yīng)激提升,通道蛋白門(mén)控動(dòng)力學(xué)性質(zhì)改變,增加了與自發(fā)痛和機(jī)械痛關(guān)聯(lián)的神經(jīng)元超興奮性。2.經(jīng)Bm K I在離體DRG神經(jīng)元直接給藥方式的電生理記錄,Bm K I能夠劑量依賴(lài)性地增大Nav1.8瞬時(shí)鈉電流和持續(xù)性鈉電流,并使Nav1.8穩(wěn)態(tài)失活、和其快、慢失活向超極化方向偏移,顯著減小了慢失活的電壓依賴(lài)性,易化了通道的激活。結(jié)果表明,Bm K I直接調(diào)制了Nav1.8的門(mén)控動(dòng)力學(xué)參數(shù),快速地點(diǎn)燃了外周傷害性感受神經(jīng)元的超興奮性。3.分別合成了Nav1.8 DIV S3-S4之間,由22個(gè)殘基組成(SIGSLLFSAILKSLENYFSPTL)的胞外環(huán)肽段和Nav1.5上相應(yīng)區(qū)域由20個(gè)殘基組成的(SIVGTVLSDIIQK—YFFSPTL)胞外環(huán)肽段(該肽段被認(rèn)為是位點(diǎn)3的結(jié)合區(qū)域之一)。經(jīng)表面等離子共振觀察到,合成的Nav1.8胞外環(huán)多肽仍能與Bm K?結(jié)合,且結(jié)合速率比與合成的Nav1.5胞外環(huán)多肽的更高,解離速率更低,結(jié)合總量則相對(duì)較低。結(jié)果表明,Nav1.8胞外環(huán)四個(gè)插入氨基酸(SLEN)并未使Nav1.8失去對(duì)Bm K I的敏感性。由此提示,Bm K I與Nav1.8的分子結(jié)合機(jī)制有別于其他位點(diǎn)3毒素。
[Abstract]:Bm K I, a specific voltage-gated sodium channel site-3, has been shown to be able to induce nociceptive behavior in rats. Nav1.8 has attracted increasing attention in its role in the development, development and maintenance of peripheral inflammatory pain and neuralgia. So is / how does Nav1.8 participate in Bm K I induced pain generation, development, and maintenance? In this paper, the cellular and molecular mechanisms of Nav1.8 involved in the regulation of peripheral signals in Bm K I induced pain model in rats were studied by means of animal behavior and electrophysiology. In this study, the electrophysiological records of Bm K I plantar injection showed that the current density of Nav1.8 in DRG neurons was significantly increased after two hours, and at the same time, the current density of Nav1.8 was significantly increased in the acutely isolated rat DRG neurons. Both the steady-state activation and steady-state inactivation curves are shifted towards hyperpolarization. Intrathecal and plantar preconditioning with A-803467(Nav1.8 selective blocker significantly reduced spontaneous and mechanical pain sensitivity in rats but had no effect on thermal pain sensitivity. The results clearly indicated that in the pain model of rats induced by BmK I, 1 / Nav1.8 acted as a stressor. That is to say, the stress response during the 2 hour short time course triggered the rapid activation of peripheral nociceptive neurons. Naval 1.8 was the main contributor to spontaneous pain and mechanical pain, that is, the stress increase of Nav1.8 expression and the change of channel protein gated dynamics. Increased hyperexcitability of neurons associated with spontaneous and mechanical pain. 2. BmK I, an electrophysiological record of direct administration of Bm K I via DRG neurons in vitro, can increase the transient sodium current and persistent sodium current of Nav1.8 in a dose-dependent manner, and make Nav1.8 inactivate stably, and shift to hyperpolarization direction with fast and slow inactivation. The voltage dependence of slow inactivation was significantly reduced, and the activation of channels was facilitated. The results show that BmK I directly modulates the gated kinetic parameters of Nav1.8 and ignites the superexcitability of peripheral nociceptive neurons. The extracellular cyclic peptide of SIGSLLFSAILKSLENYFSPTL and the extracellular cyclic peptide of SIGSLLFSAILKSLENYFSPTL, composed of 20 residues, were synthesized between Nav1.8 DIV S3-S4 and SIGSLLFSAILKLENYFSPTL, respectively. The extracyclic peptide of SIGSLLFSAILKSLENYFSPTL is considered to be one of the binding regions of site 3. It was observed by surface plasmon resonance that the synthesized extracellular polypeptide of Nav1.8 could still be associated with Bm K? The binding rate was higher, the dissociation rate was lower and the total binding rate was lower than that with the synthesized Nav1.5 extracyclic polypeptides. The results showed that Nav1.8 did not lose its sensitivity to Bm K I. It is suggested that the molecular binding mechanism of BmK I with Nav1.8 is different from that of other site 3 toxin.
【學(xué)位授予單位】：上海大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：R402

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Feng Jiang;Li-Ming Hua;Yun-Lu Jiao;Pin Ye;Jin Fu;Zhi-Jun Cheng;Gang Ding;Yong-Hua Ji;;Activation of mammalian target of rapamycin contributes to pain nociception induced in rats by BmK I, a sodium channel-specific modulator[J];Neuroscience Bulletin;2014年01期

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本文編號(hào)：1945232