Facilitation of neurotransmittcr release through activation of presynaptic P_2X receptors by endogenous ATP

通过内源性 ATP 激活突触前 P_2X 受体促进神经递质释放

基本信息

批准号：
17300123
负责人：
KATO Fusao
金额：
$ 4.47万
依托单位：
Jikei University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17300123/
关键词：
P_2X receptors astrocvtes synaptic transmission transmitter release brain slice nucleus of the solitary tract glutamate gliotransmitter caged ATP laser photolysis

项目摘要

In aiming to clarify the interaction between astrocytes and neurons in native brain tissues through the intermediary of extracellular ATP-mediated signaling, I recorded postsynaptic currents of the neurons in the nucleus of the solitary tract (NTS) in transverse brainstem slices prepared from young Wistar rats and found the followings :1. Time- (100 ms) and space- (3 μm) delimited application of ATP using DMNPE-caged ATP and "flash-and-flush" application of laser beam onto dendrites of the neuron being recorded resulted in a marked increase in the frequency of spontaneous action potential-independent excitatory postsynaptic currents (EPSC). This glutamate release facilitation was almost completely abolished by PPADS (40 μM).2. The period of release facilitation was parallel to that of laser irradiation. The laser irradiation became ineffective after displacement of the beam by a few μm from the "hot.spot" on the dendrite. Under membrane potential recording without TTX but with Cd^<2+>, … More ATP uncaging resulted in an abrupt and short-lasting increase in the firing frequency of the recorded neuron.3. Fluoroacetate, a glia-specific toxin blocking TCA cycle, reduced the spontaneous EPSC frequency.4. A P_2Y_1 receptor agonist,2-methylthio-ADP, significantly increased EPSC frequency, an effect suppressed by a P_2X receptor blocker, trinitrophenyl ATP, and fluoroacetate.5. Trinitrophenyl ATP and A-317491, a P_2X_3-selective blocker, but not fluoroacetate and deletion of P_2X_4 protein abolished the release facilitation by a,β-methylene ATP.Altogether, these novel findings suggest that activation of astrocyte network in the NTS facilitates glutamate release though ATP release from astrocytes and subsequent activation of presynaptic P_2X_2/(3) receptors on the central terminals of the primary afferent fibers. This mechanism points to a possible ATP-mediated astrocyte-to-neuron signaling enabling astrocytes to promote excitatory transmission from the primary afferents to the second-order NTS neurons. Less

为了澄清天然脑组织中星形胶质细胞与神经元之间通过细胞外ATP介导的信号传导的中介，我记录了由固体型（NTS）核中神经元的突触后电流（NTS）中的横向脑干切片中从年轻Wistar大鼠和追随者中找到的。时间 - （100 ms）和空间（3μM）使用DMNPE夹ATP和将激光束应用于记录的神经元的树突上的ATP划界ATP应用，从而显着增加了具有赞助动作的潜在无独立型兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴奋性兴高采烈（EPSC）。 PPAD（40μm）几乎完全废除了该谷氨酸释放设施。2。释放设施的时期与激光照射的时期平行。激光辐照在梁上从树突上的“热点”中移位几μm后，激光照射变得无效。在没有TTX的膜电势记录下，但具有CD^<2+>，…更多的ATP渗透导致记录的神经元的发射频率突然且短暂增加。3。氟乙酸酯是一种胶质特异性毒素阻断TCA循环，降低了赞助商EPSC频率。4。 P_2Y_1受体激动剂，2-甲基硫硫代ADP显着增加了EPSC频率，该频率被P_2X受体阻滞剂，三硝基苯基ATP和氟乙酸酯抑制的作用。5。 Trinitrophenyl ATP and A-317491, a P_2X_3-selective blocker, but not fluoroacetate and deletion of P_2X_4 protein abolished the release facility by a,β-methylene ATP.Altogether, these novel findings suggest that activation of astrocyte network in the NTS facility glutamate release though ATP release from astrocytes and subsequent主要传入纤维中心端子上的突触前P_2X_2/（3）受体的激活。该机制指出了ATP介导的星形胶质细胞到神经元信号传导，使星形胶质细胞促进了从主要传播物到二阶NTS神经元的兴奋性传播。较少的