本文關鍵詞：G蛋白偶聯(lián)受體調(diào)節(jié)GIRK通道的特異性研究　出處：《河北醫(yī)科大學》2005年碩士論文　論文類型：學位論文

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【摘要】：G 蛋白門控的內(nèi)向整流鉀離子通道(G protein gated inwardly rectifying K channels, GIRK)是內(nèi)向整流鉀通道家族中的一員(Kir3),表達于心血管和神經(jīng)組織中,它的特點是功能受G 蛋白的調(diào)節(jié)。某些G 蛋白偶聯(lián)受體可通過影響其功能影響心肌細胞、神經(jīng)細胞和神經(jīng)內(nèi)分泌細胞的興奮性。GIRK1 和GIRK4 主要分布在心房和竇房結(jié)細胞中,在調(diào)節(jié)心臟興奮性中起重要作用,由迷走神經(jīng)釋放的遞質(zhì)乙酰膽堿(Acetylcholine, ACh) 通過興奮II型毒菌堿樣受體(m2)以及下游的PTX 敏感的Gi 蛋白激活GIRK 通道,引起膜動作電位超極化,減少動作電位的頻率,減慢心率。GIRK2 主要分布在中樞神經(jīng)系統(tǒng),許多神經(jīng)遞質(zhì)如γ-氨基丁酸、多巴胺、5-羥色胺和阿片肽類等通過激活PTX 敏感的Gi 蛋白激活GIRK 通道,調(diào)節(jié)神經(jīng)細胞的興奮性。已完成的研究結(jié)果清楚地表明,GIRK 可直接被Gi 蛋白釋放的Gβγ激活,是Gβγ直接的效應VP。然而正常生理條件下只有PTX 敏感的Gi 家族G 蛋白激活后可激活GIRK 通道,而PTX 不敏感的G 蛋白如Gq 和Gs 激活后卻不能激活GIRK 通道。因此G蛋白調(diào)節(jié)GIRK 通道存在有特異性。雖然到目前為止已發(fā)現(xiàn)了5 種β亞單位和12 種γ亞單位但近來研究表明幾乎所有不同組合形式的G 均能直接激活GIRK 通道,顯然用不同G蛋白含有不同Gβγ的組合類型不能解釋G 蛋白調(diào)節(jié)GIRK通道的特異性。在本實驗中,以非洲爪蟾卵母細胞為表達系
[Abstract]:G protein gated inward rectifier potassium channel G protein gated inwardly rectifying K channels. Kirk is a member of the inward rectifier potassium channel family and is expressed in cardiovascular and neural tissues. Its function is regulated by G protein. Some G protein-coupled receptors affect cardiomyocytes by affecting its function. Excitability of nerve cells and neuroendocrine cells. GIRK1 and GIRK4 are mainly distributed in atrial and sinus node cells and play an important role in regulating cardiac excitability. Acetylcholine, a transmitter released from the vagus nerve. Ache activates the GIRK channel by stimulating the type II alkaloid receptor m2) and downstream PTX sensitive GI protein, which leads to the hyperpolarization of the membrane action potential. Reduce the frequency of action potential, slow down heart rate. GIRK2 mainly distributed in the central nervous system, many neurotransmitters such as gamma-aminobutyric acid, dopamine. 5-hydroxytryptamine and opioid peptides regulate the excitability of nerve cells by activating GIRK channels by activating the PTX sensitive GI protein. GIRK was directly activated by G 尾 緯 released by GI protein. However, under normal physiological conditions, only G protein of PTX sensitive GI family can activate GIRK channel. However, G proteins that are not sensitive to PTX, such as GQ and Gs, can not activate GIRK channel after activation. Therefore, G protein regulates GIRK. Although five 尾 subunits and 12 緯 subunits have been identified so far, recent studies have shown that almost all combinations of G can directly activate GIRK channels. Obviously, different G protein combinations containing different G 尾 緯 could not explain the specificity of G protein in regulating GIRK channels. In this study, Xenopus laevis oocytes were used as expression lines.
【學位授予單位】：河北醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2005
【分類號】：R33
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本文編號：1363629