Anandamide transport: A critical review
Anandamide transport: A critical review
复制标题
DOI：
10.1016/j.lfs.2005.05.007
复制
发表时间：
2005-08-19
期刊：
影响因子：
6.1
通讯作者：
Deutsch, DG
中科院分区：
文献类型：
--
作者：
Glaser, ST;Kaczocha, M;Deutsch, DG
在过去的十年里，已经描述了通过促进扩散来摄取花生胺(AEA)，但还没有分离出一种蛋白质。在某些类型的细胞中，最近有研究表明，AEA是一种不带电荷的疏水分子，在非蛋白质介导的过程中被动地通过质膜扩散。自那次观察以来，最近的动力学研究(使用不同的检测条件)既支持也否认AEA转运体的存在。在这篇综述中，我们分析了目前研究AEA摄取机制的文献，并试图解释产生分歧的原因。实验室间的主要变量之一是细胞与AEA的孵育时间。初始动力学(根据细胞类型的不同，在时间点和1分钟)分离发生在质膜上的事件，对于研究摄取的饱和性和据称的转运抑制剂对摄取的影响是最有用的。孵育时间较长的结果不仅反映了质膜上的事件，也反映了细胞内可能包括酶(S)、其他蛋白质或专门的脂结合结构域的相互作用。此外，在长时间孵育时，A-EA受体的拮抗剂会降低AEA的摄取。AEA转运研究中的另一个复杂因素是与塑料培养皿的非特异性结合。这种效应的大小可能超过细胞对AEA的摄取。同样，AEA可以从塑料培养皿(没有细胞)中释放，其方式类似于细胞外流。使用牛血清白蛋白的AEA运输方案，类似于用于脂肪酸摄取研究的方法，正在被接受。这可能会提高AEA溶液的稳定性，并最大限度地减少与塑料的结合，尽管一些组织报告说，BSA干扰了摄取。针对许多转运抑制剂也抑制脂肪酸酰胺水解酶(FAAH)的批评，最近合成了新的化合物。随着它们在FAAH(+/+)和FAAH(-/-)细胞和转基因小鼠中的鉴定，一些抑制剂已经被证明在FAAH(-/-)小鼠中具有生理活性。他们的靶标现在被描述为可能是AEA的蛋白质转运体。(C)2005年，爱思唯尔公司出版。
Anandamide (AEA) uptake has been described over the last decade to occur by facilitated diffusion, but a protein has yet to be isolated. In some cell types, it has recently been suggested that AEA, an uncharged hydrophobic molecule, passively diffuses through the plasma membrane in a process that is not proteinmediated. Since that observation, recent kinetics studies (using varying assay conditions) have both supported and denied the presence of an AEA transporter. In this review, we analyze the current literature exploring the mechanism of AEA uptake and endeavor to explain the reasons for the divergent views. One of the main variables among laboratories is the incubation time of the cells with AEA. Initial kinetics (at time points < 1 min depending upon the cell type) isolate events that occur at the plasma membrane and are most useful to study saturability of uptake and effects of purported transport inhibitors upon uptake. Results with longer incubation times reflect events not only at the plasma membrane but also interactions at intracellular sites that may include enzyme(s), other proteins, or specialized lipid-binding domains. Furthermore, at long incubation times, antagonists to A-EA receptors reduce AEA uptake. Another complicating factor in AEA transport studies is the nonspecific binding to plastic culture dishes. The magnitude of this effect may exceed AEA uptake into cells. Likewise, AEA may be released from plastic culture dishes (without cells) in such a manner as to mimic efflux from cells. AEA transport protocols using BSA, similar to the method used for fatty acid uptake studies, are gaining acceptance. This may improve AEA solution stability and minimize binding to plastic, although some groups report that BSA interferes with uptake. In response to criticisms that many transport inhibitors also inhibit the fatty acid amide hydrolase (FAAH), new compounds have recently been synthesized. Following their characterization in FAAH(+/+) and FAAH(-/-) cells and transgenic mice, several inhibitors have been shown to have physiological activity in FAAH(-/-) mice. Their targets are now being characterized with the possibility that a protein transporter for AEA may be characterized. (c) 2005 Published by Elsevier Inc.