Morphine promotes rapid, arrestin-dependent endocytosis of μ-opioid receptors in striatal neurons
Morphine promotes rapid, arrestin-dependent endocytosis of μ-opioid receptors in striatal neurons
复制标题
DOI：
10.1523/jneurosci.5045-04.2005
复制
发表时间：
2005-08-24
影响因子：
5.3
通讯作者：
von Zastrow, M
中科院分区：
文献类型：
--
作者：
Debic, HH;Kim, KA;von Zastrow, M
吗啡激活μ-阿片受体（MORs），而不促进它们在许多细胞类型中的快速内吞作用。以前的研究表明，吗啡可以驱动快速重新分配的MORs在丘脑核，但它是不可能的，在这个体内研究中，以确定一个特定的膜运输途径受吗啡影响，以排除可能的间接作用的吗啡通过阿片调节的神经回路，或定义这种吗啡依赖性调节的机制。在本研究中，我们解决了这些问题，使用大鼠纹状体神经元作为模型系统的分离的原代培养。吗啡促进内源性和重组MORs的快速重新分配后30分钟内药物添加到培养基中。这种作用是介导的快速内吞作用，并发生在一个细胞自主的方式，如其检测在低密度平板细胞和培养中，其中去极化被河豚毒素阻断。吗啡诱导的MORs内吞作用在数量上与脑啡肽类似物D-Ala（2）-N-Me-Phe（4）-Glycol（5）-脑啡肽诱导的相似，两种配体诱导的内吞作用均被抑制蛋白-3（β-抑制蛋白-2）的显性负突变体抑制。这些结果扩展了先前的体内结果，并表明吗啡确实能够驱动阿片类反应性CNS神经元的重要子集中的μ阿片受体的快速内吞作用。他们还提出了一种细胞机制，通过这种机制，β-抑制蛋白可以调节吗啡在体内的生理作用。
Morphine activates mu-opioid receptors (MORs) without promoting their rapid endocytosis in a number of cell types. A previous study suggested that morphine can drive rapid redistribution of MORs in the nucleus accumbens, but it was not possible in this in vivo study to identify a specific membrane trafficking pathway affected by morphine, to exclude possible indirect actions of morphine via opiate-regulated neural circuitry, or to define the mechanism of this morphine-dependent regulation. In the present study, we addressed these questions using dissociated primary cultures of rat striatal neurons as a model system. Morphine promoted a rapid redistribution of both endogenous and recombinant MORs within 30 min after drug addition to the culture medium. This effect was mediated by rapid endocytosis and occurred in a cell-autonomous manner, as indicated by its detection in cells plated at low density and in cultures in which depolarization was blocked by tetrodotoxin. Morphine-induced endocytosis of MORs was quantitatively similar to that induced by the enkephalin analog D-Ala(2)-N-Me-Phe(4)-Glycol(5)-enkephalin, and endocytosis induced by both ligands was inhibited by a dominant-negative mutant version of arrestin-3 (beta-arrestin-2). These results extend previous in vivo results and indicate that morphine is indeed capable of driving rapid endocytosis of mu-opioid receptors in an important subset of opiate-responsive CNS neurons. They also suggest a cellular mechanism by which beta-arrestins may modulate the physiological effects of morphine in vivo.