权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

DIFFERENCES IN SYNAPTIC VS NONSYNAPTIC AMPA RECEPTORS

突触与非突触 AMPA 受体的差异

基本信息

批准号：
6701770
负责人：
AMY C ARAI
金额：
$ 17.63万
依托单位：
SOUTHERN ILLINOIS UNIVERSITY SCH OF MED
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-02-09 至 2007-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6701770
关键词：
AMPA receptors clathrate concanavalin A enzyme activity enzyme inhibitors exo alpha sialidase flash photolysis glutamates heparin hippocampus laboratory rat receptor binding recombinant proteins sulfhydryl reagents synapses thiazide voltage /patch clamp

项目摘要

DESCRIPTION: AMPA-type glutamate receptors mediate most excitatory synaptic transmission in the brain. Receptor binding studies have shown that AMPA receptors exist in two distinct states with 20-fold different affinities. It is suggested that the two forms are differentially localized with synaptic receptors being of the low-affinity type and non-synaptic receptors of the high-affinity type. Thus, AMPA receptors in patches excised from the soma (and hence of non-synaptic origin) may have different kinetic properties than those in synapses. This would entail that somatic and synaptic receptors contribute differentially to neurological disorders involving excitotoxic damage to neurons. This proposition will be tested by examining if differences between synaptic and non-synaptic AMPA receptors are also detected with physiological measures and if they correspond to the high-low affinity distinction seen in binding. To facilitate this comparison, both physiological data and binding data will be collected under equivalent conditions. Aim One will determine 'physiological KD' values for equilibrium currents in patches excised from hippocampal pyramidal cells and compare them with binding affinities obtained in the same buffer and at the same temperature. The results will then be compared with similar measures from recombinant AMPA receptors stably expressed in HEK293 cells that appear to be entirely of high affinity (Aim Two) and with data from synaptic receptors in autapses of cultured neurons, which presumably are of low affinity (Aim Three). It is further known that binding to the low-affinity receptors can be modulated about two-fold by biochemical manipulations such as treatment with concanavalin A, phospholipase A2 or neuroaminidase. The consequences of some of these treatments for AMPA receptor kinetics will be examined in Aim Four using the same approach. It was also observed that high affinity receptors, unlike their low-affinity counterpart, are highly unstable at 37 degrees C and it seems likely that this is related to the fast 'run-down' of AMPA receptor currents in patch experiments. Determining which cellular factor stabilizes the low-affinity receptors will constitute the Fifth Aim of this application.

描述：AMPA型谷氨酸受体介导大多数兴奋性突触，大脑中的传输。受体结合研究表明，AMPA 受体以亲和力相差20倍的两种不同状态存在。是这表明，这两种形式是差异定位与突触受体是低亲和力类型和非突触受体的高亲和力类型。因此，从索马切除的斑块中的AMPA受体（和因此是非突触起源）可能具有不同于那些神经突触这意味着躯体和突触受体与涉及兴奋性毒性损伤的神经系统疾病不同，神经元这一命题将通过检查是否存在差异来检验，突触和非突触AMPA受体也可以用生理学方法检测到。测量，如果它们对应于约束力为了便于这种比较，生理数据和绑定数据将在同等条件下收集。目标一将决定从离体斑块中的平衡电流的“生理KD”值海马锥体细胞，并将它们与获得的结合亲和力进行比较在相同的缓冲液和温度下。结果将是与来自稳定表达的重组AMPA受体的类似测量相比，在HEK293细胞中，似乎完全具有高亲和力（目的二），来自培养神经元autapses的突触受体的数据，低亲和力（目标三）。进一步已知的是，结合到低亲和力受体可被生物化学调节约两倍，操作，例如用伴刀豆球蛋白A、磷脂酶A2或神经氨酸酶这些AMPA受体治疗的结果在目标四中将使用相同的方法来检查动力学。也是观察到高亲和力受体，不像它们的低亲和力对应物，在37摄氏度时非常不稳定，这似乎与在贴片实验中AMPA受体电流的快速“下降”。确定哪种细胞因子稳定低亲和力受体将构成第五，本申请的目的。