Quantitative immunolocalization of mu opioid receptors: Regulation by naltrexone
Quantitative immunolocalization of mu opioid receptors: Regulation by naltrexone
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DOI：
10.1016/s0306-4522(97)00659-3
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发表时间：
1998-08-01
期刊：
影响因子：
3.3
通讯作者：
Evans, CJ
中科院分区：
文献类型：
--
作者：
Unterwald, EM;Anton, B;Evans, CJ
本研究利用一种新开发的定量免疫组织化学测定来测量长期给予阿片受体拮抗剂纳洛酮后μ阿片受体丰度的变化。将这些数据与从相邻组织切片上的mu受体放射性配体结合获得的数据进行比较，以确定特征性拮抗剂诱导的放射性配体结合增加是否是由于mu受体总数增加和/或在受体总数没有变化的情况下处于活性结合构象的受体比例增加。成年雄性Sprague-Dawley大鼠通过渗透微泵连续7天给予纳洛酮（7-8 mg/kg/天）或盐水，此后对其脑进行处理，用于免疫组织化学和相邻新鲜冷冻组织切片上的受体放射自显影。使用放射性标记的二抗进行放射自显影测定和一组放射性标准品进行半定量免疫组织化学。结果表明，除了少数例外，两种不同方法测量的μ阿片受体分布之间总体一致。纳洛酮给药后，mu受体免疫反应性显着高于杏仁核，丘脑，海马，脚间核与生理盐水处理的对照组动物相比。[H-3]D-Ala（2），N-Me-Phe（4），Gly-ol（5）-脑啡肽与μ阿片受体的结合在纳洛酮处理的大鼠的苍白球、杏仁核、丘脑、下丘脑、海马、黑质、腹侧被盖区、中央灰质和脚间核中显著更高。这些发现表明在某些脑区，慢性纳洛酮暴露增加μ阿片受体的总数，而在其它区域中，活性受体的百分比增加，而受体的总数没有可观察到的变化。定量受体免疫检测结合配体放射自显影为研究组织切片上μ阿片受体的调节提供了一种新的方法。(C)1998年IBRO。出版社：Elsevier Science Ltd
The present study utilized a newly developed quantitative immunohistochemical assay to measure changes in mu opioid receptor abundance following chronic administration of the opioid receptor antagonist naltrexone. These data were compared with those obtained From mu receptor radioligand binding on adjacent tissue sections, in order to determine whether the characteristic antagonist-induced increase in radioligand binding is due to an increase in the total number of mu receptors and/or to an increase in the proportion of receptors that are in an active binding conformation in the absence of a change in the total number of receptors. Adult male Sprague-Dawley rats were administered naltrexone, 7-8 mg/kg per day, or saline continuously for seven days by osmotic minipumps, after which time their brains were processed for immunohistochemistry and receptor autoradiography on adjacent fresh frozen tissue sections. Semiquantitative immunohistochemistry was performed using a radiolabelled secondary antibody for autoradiographic determination and a set of radioactive standards. Results demonstrate an overall concordance between the distribution of mu opioid receptors as measured by the two different methods with a few exceptions. Following naltrexone administration, mu receptor immunoreactivity was significantly higher in the amygdala, thalamus, hippocampus, and interpeduncular nucleus as compared with the saline-treated control animals. [H-3]D-Ala(2),N-Me-Phe(4),Gly-ol(5)-enkephalin binding to mu opioid receptors was significantly higher in the globus pallidus, amygdala, thalamus, hypothalamus, hippocampus, substantia nigra, ventral tegmental area, central gray, and interpeduncular nucleus of the naltrexone-treated rats.These findings indicate that in some brain regions chronic naltrexone exposure increases the total number of mu opioid receptors, while in other regions there is an increase in the percent of active receptors without an observable change in the total number of receptors. Quantitative receptor immunodetection together with ligand autoradiography provides a new approach for investigating the regulation of mu opioid receptors on tissue sections. (C) 1998 IBRO. Published by Elsevier Science Ltd.