MOR Phosphorylation in Opioid Tolerance and Dependence

激动剂诱导的阿片受体磷酸化被认为是一个重要的受体调节过程 促进急性受体脱敏，触发受体的内化和回收，并且 参与宽容的发展。细胞研究中的大量实验证据 表达克隆的阿片受体的细胞系表明，莫尔磷酸化的程度一般是 依赖于配体功效，但也可能受到具有相似功效的配体的不同影响 （例如，吗啡与美沙酮）和不同细胞中的特异性信号分子（CHO与HEK）。 这意味着莫尔磷酸化在不同的脑区可能具有不同的作用。但这 尚未在神经元系统和整个动物中得到证实。因此，拟议的研究是 目的是检验以下假设：莫尔磷酸化是激动剂依赖性的， 细胞特异性，受体的微环境和细胞信号传导成分影响的程度， 磷酸化和体内差异耐受性和依赖性的发展。使用原代 作为DRG神经元的培养模型，PI建议检查DRG神经元中的莫尔磷酸化 和其他脑区;以评估其对脱敏和其他受体调节的贡献。 过程中使用磷酸化缺陷突变受体，并确定是否细胞特异性μ 磷酸化是不同信号传导组分（例如不同蛋白质）参与的结果 在DRG和其他脑区域之间的激酶）。PI还建议确定受体的作用 二聚化对莫尔磷酸化的影响，探索受体二聚化对MOR磷酸化的可能贡献。 受体磷酸化的潜在区域变化和阿片耐受性的发展。的PI 进一步提出通过改变动物中的莫尔磷酸化状态来在体内检验该假设 通过使用敲入方法产生莫尔磷酸化缺陷突变小鼠。因此 这些结果可能有助于更好地理解莫尔磷酸化和其他蛋白质之间的动态相互作用。 受体调节过程的神经元，并提供潜在的解释机制， 阿片类药物之间耐受性和依赖性的不同发展以及更多的 有效的治疗。

Agonist-induced opioid receptor phosphorylation is believed to be an important receptor regulatory process that promotes acute receptor desensitization, triggers internalization and recycling of the receptors, and participates the development of tolerance. Numerous lines of experimental evidence from studies of cell lines that express cloned opioid receptor indicate that in general the extent of MOR phosphorylation is dependent on the ligand efficacy, but also could be influenced differentially by ligands with similar efficacy (morphine vs methadone, for example) and specific signaling molecules in the different cells (CHO vs HEK). This implies that MOR phosphorylation could have differential roles in different brain regions. However, this has not been demonstrated in neuronal systems and whole animals. Therefore, the proposed research is aimed at testing the following hypothesis: MOR phosphorylation is agonist-dependent as well as region or cell specific, and the receptor's microenvironment and cellular signaling components influence the extent of phosphorylation and the development of differential tolerance and dependence in vivo. Using primary culture of DRG neurons as a model, the PI proposes to examine the MOR phosphorylation in DRG neuron and other brain regions; to evaluate its contribution to desensitizationin and other receptor regulatory processes by using phosphorylation-deficient mutant receptors; and to determine if cellular specific mu phosphorylation is a result of participation of different signaling components (such as different protein kinases) among the DRG and other brain regions. The PI also proposes to determine the effect of receptor dimerization on MOR phosphorylation, exploring the possible contributions of receptor dimerization to the potential regional variation in receptor phosphorylation and the development of opioid tolerence. The PI further proposes to test the hypothesis in vivo by modifying the MOR phosphorylation status in animal through generating MOR phosphorylation-deficient mutant mice using a knock-in approach. Thus, the results could lead to a better understanding the dynamic interplay between MOR phosphorylation and other receptor regulatory processes in neurons, and to provide potential explanations on the mechanism of differential development of tolerance and dependence among opioid drugs and new foundations for more effective therapies.