鯽魚視網(wǎng)膜水平細胞谷氨酸受體對γ-氨基丁酸轉(zhuǎn)運體的調(diào)控
發(fā)布時間：2019-05-18 17:15
【摘要】： 水平細胞是視網(wǎng)膜內(nèi)核層的抑制性中間神經(jīng)元,接受來自光感受器細胞的谷氨酸能輸入,同時通過GABA轉(zhuǎn)運體釋放GABA,參與水平細胞對光感受器細胞的反饋調(diào)節(jié),及雙極細胞和神經(jīng)節(jié)細胞的中心外周拮抗的感受野的形成。谷氨酸可以激活水平細胞膜上的包括NMDA受體和AMPA受體在內(nèi)的谷氨酸受體。已有報道證明激活鰩魚視網(wǎng)膜水平細胞的AMPA受體可以抑制GABA轉(zhuǎn)運體電流。我們應用全細胞膜片鉗技術,在鯽魚視網(wǎng)膜上也發(fā)現(xiàn)了類似的現(xiàn)象,激活鯽魚視網(wǎng)膜水平細胞的AMPA受體也可以抑制GABA轉(zhuǎn)運體電流。由于NMDA受體是最近在鯽魚水平細胞上發(fā)現(xiàn)的,其功能尚不清楚。我們因此對激活NMDA受體是否能調(diào)節(jié)GABA轉(zhuǎn)運體電流進行了研究。實驗結(jié)果顯示,激活水平細胞的NMDA受體可以抑制GABA轉(zhuǎn)運體電流。NMDA受體的阻斷劑AP-5(100μM)可以消除這個效應。說明這種效應是通過激活NMDA受體來實現(xiàn)的。當使用無鈣的Ringer’s液灌流的時候,這種NMDA對GABA轉(zhuǎn)運體的抑制就會被解除。當胞內(nèi)鈣庫的鈣釋放和回收被20μM ryanodine + 2μM thapsigargin灌流3 min所阻斷后,NMDA對GABA轉(zhuǎn)運體的抑制作用也會被減弱。在全細胞模式膜片鉗形成的時候,電極內(nèi)液中10 mM的BAPTA經(jīng)5 min擴散到細胞內(nèi)后,這種NMDA的抑制效應也被削弱。以上結(jié)果說明激活NMDA受體可以通過影響胞內(nèi)鈣過程來調(diào)節(jié)GABA轉(zhuǎn)運體的活動。進一步地,基于本實驗室以前的工作,用數(shù)學方程構建了一個含有內(nèi)質(zhì)網(wǎng)膜和細胞膜的細胞模型來定量地分析NMDA引起的Ca2+動力學及GABA轉(zhuǎn)運體電流的變化。模型結(jié)果提示,胞內(nèi)鈣庫活動參與NMDA受體對GABA轉(zhuǎn)運體活動的調(diào)節(jié)。 除了鯽魚,在大鼠和人的視網(wǎng)膜水平細胞上也存在NMDA受體,但是水平細胞上NMDA受體的生理功能尚不清楚。本文在鯽魚視網(wǎng)膜水平細胞上發(fā)現(xiàn)激活NMDA受體可以抑制GABA轉(zhuǎn)運體的活動。在生理條件下,視網(wǎng)膜光感受器細胞在暗中持續(xù)釋放谷氨酸,水平細胞上的鈣通透的AMPA受體和NMDA受體均會被激活,胞外鈣離子就會通過這兩種受體進入胞內(nèi),發(fā)揮抑制GABA轉(zhuǎn)運體的作用。相對于AMPA受體的快速失敏,NMDA受體的失敏很慢。提示生理條件下NMDA受體在對GABA轉(zhuǎn)運體的抑制性調(diào)控可能發(fā)揮更重要的作用。
[Abstract]:Horizontal cells are inhibitory intermediate neurons in the inner nuclear layer of the Retin. they receive glutamic acid input from photoreceptor cells and release GABA, through GABA transporter to participate in the feedback regulation of horizontal cells to photoreceptor cells. And the formation of central peripheral antagonistic receptive fields of bipolar cells and ganglion cells. Glutamate can activate glutamate receptors on horizontal cell membrane, including NMDA receptor and AMPA receptor. It has been reported that activating AMPA receptors in horizontal cells of rays can inhibit GABA transporter current. Using whole-cell patch clamp technique, a similar phenomenon was found in the retinal of crucian carp. The activation of AMPA receptor in the horizontal cells of crucian carp can also inhibit the current of GABA transporter. Because NMDA receptor was recently found in crucian carp horizontal cells, its function is not clear. Therefore, we studied whether the activation of NMDA receptor can regulate the current of GABA transporter. The results showed that the activation of NMDA receptor in horizontal cells could inhibit the current of GABA transporter. AP-5 (100 渭 M), the blocker of NMDA receptor, could eliminate this effect. It is suggested that this effect is achieved by activating NMDA receptor. When perfused with calcium-free Ringer's solution, the inhibition of GABA transporter by this NMDA is relieved. When the calcium release and recovery of intracellular calcium pool were blocked by 20 渭 M ryanodine 2 渭 M thapsigargin perfusion for 3 min, the inhibitory effect of NMDA on GABA transporter was also weakened. When the whole cell mode patch clamp was formed, the inhibitory effect of 10 mM BAPTA in the electrode solution was also weakened after 5 min diffusion into the cell. These results suggest that the activation of NMDA receptor can regulate the activity of GABA transporter by affecting the intracellular calcium process. Furthermore, based on the previous work in our laboratory, a cell model containing endoplasmic reticulum and cell membrane was constructed by mathematical equation to quantitatively analyze the changes of Ca2 kinetics and GABA transporter current induced by NMDA. The results of the model suggest that intracellular calcium pool activity is involved in the regulation of GABA transporter activity by NMDA receptors. In addition to crucian carp, NMDA receptors also exist in rat and human retinal horizontal cells, but the physiological function of NMDA receptors in horizontal cells is not clear. It was found that activation of NMDA receptor could inhibit the activity of GABA transporter in horizontal cells of crucian carp. Under physiological conditions, retinal photoreceptor cells continue to release glutamate in the dark, calcium permeable AMPA receptors and NMDA receptors on horizontal cells will be activated, and extracellular calcium ions will enter the cells through these two receptors. Play an important role in inhibiting GABA transporter. Compared with the rapid desensitization of AMPA receptor, the desensitization of NMDA receptor is very slow. It is suggested that NMDA receptor may play a more important role in the inhibitory regulation of GABA transporter under physiological conditions.
【學位授予單位】：上海交通大學
【學位級別】：博士
【學位授予年份】：2009
【分類號】：R33
本文編號：2480189
[Abstract]:Horizontal cells are inhibitory intermediate neurons in the inner nuclear layer of the Retin. they receive glutamic acid input from photoreceptor cells and release GABA, through GABA transporter to participate in the feedback regulation of horizontal cells to photoreceptor cells. And the formation of central peripheral antagonistic receptive fields of bipolar cells and ganglion cells. Glutamate can activate glutamate receptors on horizontal cell membrane, including NMDA receptor and AMPA receptor. It has been reported that activating AMPA receptors in horizontal cells of rays can inhibit GABA transporter current. Using whole-cell patch clamp technique, a similar phenomenon was found in the retinal of crucian carp. The activation of AMPA receptor in the horizontal cells of crucian carp can also inhibit the current of GABA transporter. Because NMDA receptor was recently found in crucian carp horizontal cells, its function is not clear. Therefore, we studied whether the activation of NMDA receptor can regulate the current of GABA transporter. The results showed that the activation of NMDA receptor in horizontal cells could inhibit the current of GABA transporter. AP-5 (100 渭 M), the blocker of NMDA receptor, could eliminate this effect. It is suggested that this effect is achieved by activating NMDA receptor. When perfused with calcium-free Ringer's solution, the inhibition of GABA transporter by this NMDA is relieved. When the calcium release and recovery of intracellular calcium pool were blocked by 20 渭 M ryanodine 2 渭 M thapsigargin perfusion for 3 min, the inhibitory effect of NMDA on GABA transporter was also weakened. When the whole cell mode patch clamp was formed, the inhibitory effect of 10 mM BAPTA in the electrode solution was also weakened after 5 min diffusion into the cell. These results suggest that the activation of NMDA receptor can regulate the activity of GABA transporter by affecting the intracellular calcium process. Furthermore, based on the previous work in our laboratory, a cell model containing endoplasmic reticulum and cell membrane was constructed by mathematical equation to quantitatively analyze the changes of Ca2 kinetics and GABA transporter current induced by NMDA. The results of the model suggest that intracellular calcium pool activity is involved in the regulation of GABA transporter activity by NMDA receptors. In addition to crucian carp, NMDA receptors also exist in rat and human retinal horizontal cells, but the physiological function of NMDA receptors in horizontal cells is not clear. It was found that activation of NMDA receptor could inhibit the activity of GABA transporter in horizontal cells of crucian carp. Under physiological conditions, retinal photoreceptor cells continue to release glutamate in the dark, calcium permeable AMPA receptors and NMDA receptors on horizontal cells will be activated, and extracellular calcium ions will enter the cells through these two receptors. Play an important role in inhibiting GABA transporter. Compared with the rapid desensitization of AMPA receptor, the desensitization of NMDA receptor is very slow. It is suggested that NMDA receptor may play a more important role in the inhibitory regulation of GABA transporter under physiological conditions.
【學位授予單位】：上海交通大學
【學位級別】：博士
【學位授予年份】：2009
【分類號】：R33
【引證文獻】
相關碩士學位論文 前1條
1 張雅婷;胞外鋅離子對鯽魚視網(wǎng)膜水平細胞上表達的內(nèi)向整流鉀通道的調(diào)控特性[D];上海交通大學;2011年
，本文編號：2480189
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