本文選題：下丘　切入點：NMDA受體　出處：《中國科學(xué)技術(shù)大學(xué)》2011年碩士論文

【摘要】：背景:當(dāng)細胞膜上兩個不同的離子受體同時被激活時,他們之間往往會存在一種功能性的相互調(diào)節(jié),即一種受體的激活會抑制或增強另一種受體的反應(yīng),這種受體間的相互調(diào)節(jié)作用被叫做受體間的相互對話。這種受體間的相互對話對神經(jīng)元的興奮性和神經(jīng)信號的加工整合等具有重要的作用和生理意義。N-甲基-D-門冬氨酸(NMDA)型谷氨酸受體和γ-氨基丁酸A(GABA_A)型受體分別是中樞神經(jīng)系統(tǒng)中主要的興奮性和抑制性受體。至今為止,關(guān)于這兩種受體之間的功能相互作用還缺乏系統(tǒng)和詳盡的研究,特別在中樞聽覺系統(tǒng)中,關(guān)于這兩種受體之間的功能交互作用至今還未見相關(guān)的報道。下丘是中樞聽覺通路中重要的信息整合中心,NMDA受體和GABA_A受體在該神經(jīng)核團上均有豐富的表達。本論文旨在探討大鼠下丘神經(jīng)元上NMDA受體和GABA_A受體之間的功能交互作用及可能的機制。 方法:本研究在原代培養(yǎng)的新生大鼠下丘神經(jīng)元上采用傳統(tǒng)的全細胞膜片鉗的方法研究NMDA受體和GABA_A受體之間的交互作用。在對膜電流的記錄過程中采用的是電壓鉗模式,并且保持被記錄細胞的膜電壓始終被鉗制在-60 mV。在本實驗中藥物的施加是通過一種被稱為“Y管給藥”的快速給藥系統(tǒng)。 結(jié)果:(1)100μM的GABA可抑制100μM Asp在下丘神經(jīng)元激活的全細胞電流(IAsp),表明GABA_A受體的激活能夠抑制NMDA受體的功能。GABA_A受體的競爭性拮抗劑bicuculline(10μM)可完全阻斷GABA激活的電流,并可消除GABA對IAsp的抑制作用;(2)100μM的Asp對高濃度(100μM )GABA在下丘神經(jīng)元激活的全細胞電流(IGABA)沒有影響,但對低濃度(3μM)GABA激活的IGABA有抑制作用,表明NMDA受體的激活對GABA_A受體的抑制作用是濃度依賴性的。NMDA受體的競爭性拮抗劑APV(100μM)可完全阻斷Asp激活的電流,并可消除Asp對IGABA的抑制作用;(3)細胞外液中加入電壓依賴的鈣通道(VDCC_s)的阻斷劑CdCl_2不影響Asp對IGABA的抑制作用,但是當(dāng)外液中無鈣或在電極內(nèi)液中加入鈣的螯合劑BAPTA時,Asp對IGABA的抑制作用消失,說明這種抑制作用是由鈣離子介導(dǎo)的,并且是鈣離子通過NMDA受體通道內(nèi)流而非經(jīng)由VDCCs內(nèi)流而發(fā)揮作用的;(4)Asp對IGABA的抑制作用可被鈣-鈣調(diào)素依賴性的蛋白激酶Ⅱ(CaMKⅡ)的抑制劑KN-62所阻斷,說明在NMDA受體和GABA_A受體的功能交互作用中,CaMKⅡ起到了重要的作用。 結(jié)論:本論文的研究結(jié)果表明,在培養(yǎng)的下丘神經(jīng)元上,NMDA受體和GABA_A受體之間存在相互抑制的作用。這兩種受體間的交互作用是一個鈣依賴性的過程,但并不是通過激活電壓依賴的鈣通道來起作用的,其下游機制與細胞內(nèi)的CaMKⅡ有關(guān)。NMDA和GABA_A受體在下丘的交互作用提示了中樞聽覺系統(tǒng)中信息加工方式的復(fù)雜性。
[Abstract]:Background: when two different ion receptors on the cell membrane are activated at the same time, there is often a functional interaction between them, that is, the activation of one receptor inhibits or enhances the response of the other. The interaction between the receptors is called the interaction between the receptors. The interaction between the receptors plays an important role in neuronal excitability and neural signal processing and integration. Aspartate NMDA-type glutamate receptors and 緯 -aminobutyric acid (GABA) type receptors are the main excitatory and inhibitory receptors in the central nervous system. There is a lack of systematic and detailed research on the functional interactions between these two receptors, especially in the central auditory system. The functional interaction between these two receptors has not been reported yet. The inferior colliculus is an important information integration center in the central auditory pathway. Both NMDA receptor and GABA_A receptor are expressed in the neuronal nuclei. The purpose of this study was to investigate the functional interaction between NMDA receptor and GABA_A receptor in rat inferior colliculus neurons and its possible mechanism. Methods: in this study, the interaction between NMDA receptor and GABA_A receptor was studied by traditional whole-cell patch clamp method on primary cultured rat inferior colliculus neurons. The membrane voltage of the recorded cells was maintained at -60 MV. In this experiment, the drug was applied through a rapid delivery system called "Y tube delivery". Results 100 渭 M GABA could inhibit the whole cell current activated by 100 渭 M Asp in the inferior colliculus neurons, suggesting that the activation of GABA_A receptor could inhibit the function of NMDA receptor. Bicuculline(10 渭 M, a competitive antagonist of GABA A receptor, could completely block the GABA activated current. The inhibitory effect of GABA on IAsp was also eliminated. The inhibitory effect of 100 渭 M Asp on the whole cell current (IGABA) activated by 100 渭 M GABA in the inferior colliculus neurons was not affected, but it inhibited the IGABA activated by 3 渭 M)GABA at low concentration. It was suggested that the inhibitory effect of NMDA receptor activation on GABA_A receptor was that APV(100 渭 M, a competitive antagonist of. NMDA receptor in a concentration dependent manner, could completely block the current activated by Asp. The inhibitory effect of Asp on IGABA was also eliminated. The addition of voltage-dependent calcium channel (VDCCs) blocker CdCl_2 into extracellular fluid did not affect the inhibitory effect of Asp on IGABA. However, the inhibitory effect of Asp on IGABA disappeared when there was no calcium in the external solution or when the calcium chelator BAPTA was added to the electrode solution, indicating that the inhibition was mediated by calcium ion. Moreover, the inhibition of IGABA by calcium acting through the influx of NMDA receptor channel rather than through the influx of VDCCs can be blocked by KN-62, an inhibitor of calcium calmodulin dependent protein kinase 鈪，

本文編號：1694467