肢端酸A对[3H]- kainic酸和[3H]-AMPA与大鼠脑突触质膜结合的影响。

Effects of acromelic acid A on the binding of [3H]-kainic acid and [3H]-AMPA to rat brain synaptic plasma membranes.

作者信息

Smith A L, McIlhinney R A

机构信息

MRC Anatomical Neuropharmacology Unit, Oxford.

出版信息

Br J Pharmacol. 1992 Jan;105(1):83-6. doi: 10.1111/j.1476-5381.1992.tb14214.x.

DOI:10.1111/j.1476-5381.1992.tb14214.x

PMID:1375859

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1908608/

Abstract

The ability of acromelic acid A to inhibit [3H]-kainic acid and [3H]-(RS)-alpha-amino-3-hydroxy-5-methyloxazole-4-propionic acid ([3H]-AMPA) binding to rat brain synaptic plasma membranes was investigated by equilibrium radioligand binding assay. 2. Kinetic analysis of [3H]-kainic acid binding demonstrated the existence of two kainate binding sites in this tissue preparation and yielded equilibrium dissociation constants for [3H]-kainic acid of KD = 0.4 nM and KD = 20.8 nM. 3. Kainic acid and domoic acid both appeared to displace [3H]-kainic acid from a single binding site with equilibrium binding constants of KD = 19.4 nM and Ki = 14.5 nM respectively. Acromelic acid A exhibited a biphasic inhibition of [3H]-kainic acid binding to synaptic membranes with binding affinities of Ki = 15.1 nM and Ki = 1.49 microM. 4. In the absence of chaotropic ions, the order of potency of inhibition of [3H]-AMPA binding was acromelic acid A (Ki = 26 nM) greater than AMPA (KD = 184 nM) greater than domoic acid (Ki = 499 nM). 5. The inclusion of 100 mM thiocynanate ion in the [3H]-AMPA binding assay resulted in a change in the order of potency to: AMPA (KD = 160 nM) greater than acromelic acid A (Ki = 289 nM) greater than domoic acid (Ki = 9.02 microM). 6. These results show that acromelic acid A distinguishes two kainate binding sites in rat brain synaptic plasma membranes and in addition, that in the absence of chaotropic ions, acromelic acid A is the most potent displacer of [3H]-AMPA binding yet described.

摘要

通过平衡放射性配体结合试验研究了肢端酸A抑制[3H]-海藻酸和[3H]-(RS)-α-氨基-3-羟基-5-甲基恶唑-4-丙酸([3H]-AMPA)与大鼠脑突触质膜结合的能力。2. [3H]-海藻酸结合的动力学分析表明，在该组织制剂中存在两个海藻酸盐结合位点，并得出[3H]-海藻酸的平衡解离常数KD = 0.4 nM和KD = 20.8 nM。3. 海藻酸和软骨藻酸似乎都从单个结合位点上取代了[3H]-海藻酸，平衡结合常数分别为KD = 19.4 nM和Ki = 14.5 nM。肢端酸A对[3H]-海藻酸与突触膜结合表现出双相抑制作用，结合亲和力为Ki = 15.1 nM和Ki = 1.49 μM。4. 在没有离液剂离子的情况下，抑制[3H]-AMPA结合的效力顺序为：肢端酸A（Ki = 26 nM）大于AMPA（KD = 184 nM）大于软骨藻酸（Ki = 499 nM）。5. 在[3H]-AMPA结合试验中加入100 mM硫氰酸根离子导致效力顺序变为：AMPA（KD = 160 nM）大于肢端酸A（Ki = 289 nM）大于软骨藻酸（Ki = 9.02 μM）。6. 这些结果表明，肢端酸A在大鼠脑突触质膜中区分出两个海藻酸盐结合位点，此外，在没有离液剂离子的情况下，肢端酸A是迄今所描述的最有效的[3H]-AMPA结合取代剂。