Excitotoxicity at both NMDA and non-NMDA glutamate receptors is antagonized by aurintricarboxylic acid: evidence for differing mechanisms of action.
Excitotoxicity at both NMDA and non-NMDA glutamate receptors is antagonized by aurintricarboxylic acid: evidence for differing mechanisms of action.
复制标题
NMDA 和非 NMDA 谷氨酸受体的兴奋毒性均被金精三羧酸拮抗：不同作用机制的证据。
DOI：
10.1046/j.1471-4159.1995.64041749.x
复制
发表时间：
1995
影响因子：
4.7
通讯作者：
Nicklas,WJ
中科院分区：
文献类型：
--
作者：
Zeevalk,GD;Schoepp,D;Nicklas,WJ
在这项研究中，研究人员检测了核酸内切酶抑制剂金羧酸（ATA）减轻NMDA和非NMDA谷氨酸受体介导的急性和延迟性兴奋毒性的能力。体外胚胎鸡视网膜是一种经常用于兴奋性毒性研究的模型系统，将其暴露于100µMNMDA或kainate （KA）±不同浓度的ATA中60分钟，然后让其恢复24小时。乳酸脱氢酶释放到培养基中并评估组织学作为延迟毒性的措施。ATA以剂量依赖的方式减弱NMDA或KA引起的乳酸脱氢酶释放。组织学显示，ATA减少了对谷氨酸激动剂的收缩谱的数量。讨论了ATA保护的机理。发现ATA阻断NMDA‐但不阻断KA‐介导的22na +内流和环状GMP的形成。在膜结合研究中，ATA对NMDA受体的位移具有相对的选择性。[3H]CGS 19755、α‐[3H]氨基‐3‐羟基‐5‐甲基异唑‐4‐丙酸（[3H]AMPA）和[3H]KA的ic50位移值分别为29.9±1.3、313±46和bbb10 000µM±SEM。通过组织肿胀和培养基中GABA的增加进行组织学监测，ATA也完全减弱了NMDA诱导的和部分减弱了KA诱导的急性兴奋毒性。对ATA有效性的时间研究表明，ATA需要在NMDA暴露期间存在才能提供保护，但与KA相比，如果在KA暴露后立即施用，则同样有效。尽管在无细胞系统中，ATA是磷酸果糖激酶活性和蛋白质合成的有效抑制剂，但由于与100µMATA孵育60分钟对乳酸形成或[3H]亮氨酸并入三氯乙酸可沉淀物质没有影响，因此提出了关于ATA细胞渗透的问题。这些研究表明，ATA可以防止NMDA或非NMDA谷氨酸受体介导的兴奋性毒性。抗NMDA的保护机制是通过阻断NMDA受体的相互作用。ATA对KA受体无直接作用；因此，其对KA的保护机制不同于对NMDA的保护机制，目前尚不清楚。
In this study, the endonuclease inhibitor aurintricarboxylic acid (ATA) was examined for its ability to attenuate both acute and delayed excitotoxicity mediated through NMDA and non‐NMDA glutamate receptors. Ex vivo embryonic chick retina, a model system frequently used for studies of excitotoxicity, was exposed to either 100 µMNMDA or kainate (KA) ± various concentrations of ATA for 60 min, then allowed to recover for 24 h. Lactate dehydrogenase release into the medium and histology were assessed as measures of delayed toxicity. ATA attenuated lactate dehydrogenase release due to NMDA or KA in a dose‐dependent manner. Histology revealed that ATA decreased the number of pyknotic profiles in response to either glutamate agonist. The mechanism of ATA protection was addressed. ATA was found to block NMDA‐ but not KA‐mediated22Na+influx and cyclic GMP formation. In membrane binding studies, ATA was relatively selective for displacement at the NMDA receptor. The IC50values for displacement of [3H]CGS 19755, α‐[3H]amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid ([3H]AMPA), or [3H]KA were 29.9 ± 1.3, 313 ± 46, and >1,000 µM± SEM, respectively. ATA also fully attenuated NMDA‐induced and partially attenuated KA‐induced acute excitotoxicity as monitored histologically by tissue swelling and by the increase in GABA in the medium. Temporal studies of ATA efficacy indicated that ATA needed to be present during NMDA exposure to afford protection but, versus KA, was equally effective if administered immediately after KA exposure. Questions regarding the cellular penetration of ATA were raised because incubation with 100 µMATA for 60 min had no effect on lactate formation or [3H]leucine incorporation into trichloroacetic acid‐precipitable material, even though, in cell‐free systems, ATA is a potent inhibitor of phosphofructokinase activity and protein synthesis. These studies demonstrate that ATA can protect against excitotoxicity mediated through NMDA or non‐NMDA glutamate receptors. The mechanism of protection versus NMDA is through interruption of NMDA receptor interactions. ATA has no direct effect at the KA receptor; thus, its mechanism of protection versus KA is distinct from that versus NMDA and is, at present, unknown.