Quantitative autoradiographic mapping of opioid receptors in the brain of δ-opioid receptor gene knockout mice
Quantitative autoradiographic mapping of opioid receptors in the brain of δ-opioid receptor gene knockout mice
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DOI：
10.1016/s0006-8993(02)02452-6
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发表时间：
2002-07-26
期刊：
影响因子：
2.9
通讯作者：
Kitchen, I
中科院分区：
文献类型：
--
作者：
Goody, RJ;Oakley, SM;Kitchen, I
使用定量受体放射自显影技术，我们已经确定了增量阿片受体基因(Oprd1)的缺失是否会导致其他阿片受体表达的代偿性变化。用基因打靶技术删除小鼠β-阿片受体基因的外显子I，并对野生型、杂合子和纯合子基因敲除小鼠的脑进行放射自显影。用[H-3]Deltorphin 1(7 NM)标记Delta-阿片受体，用[H-3]DAMGO(4 NM)标记mU-，用[H-3]CI-977(2.5 nM)或[H-3]bremazocine(2 NM)标记kappa-，用纳洛酮测定非特异性结合。[H-3]在杂合子动物中，Deltorphin I结合减少了大约50%。在纯合子动物中，只有在长期接触胶片(12周)后才能检测到特异性结合。显示这种残留的[H-3]Deltorphin I结合的区域与那些显示高水平Mu受体的区域显著相关，并且在Mu激动剂DAMGO的存在下被取消。放射自显影显示，在Oprd1基因的两个拷贝丢失后，[H-3]DAMGO和[H-3]CI-977在整个大脑中的结合显著减少。相比之下，来自-/-小鼠的大脑中[H-3]Bremazocine结合的总体水平高于+/+小鼠。我们的发现表明，Delta受体基因敲除小鼠大脑中残留的[H-3]Deltorphin I结合是与Mu位点交叉反应的结果，不存在来自不同基因的Delta受体亚型。Mu受体和kappa受体标记的变化表明，这些亚型的代偿性变化是对Delta受体缺失的反应。[H-3]CI-977和[H-3]bremazocine结合的差异表明这些配体对kappa受体具有不同的识别能力。(C)2002 Elsevier Science B.V.保留所有权利。
Using quantitative receptor autoradiography we have determined if deletion of the delta-opioid receptor gene (Oprd1) results in compensatory changes in the expression of other opioid receptors. Gene targeting was used to delete exon I of the mouse delta-opioid receptor gene and autoradiography was carried out on brains from wild-type, heterozygous and homozygous knockout mice. delta-Opioid receptors were labeled with [H-3]deltorphin 1 (7 nM), mu- with [H-3]DAMGO (4 nM), and kappa- with [H-3]CI-977 (2.5 nM) or [H-3]bremazocine (2 nM in the presence of DPDPE and DAMGO) and non-specific binding determined with naloxone. [H-3]Deltorphin I binding was reduced by approximately 50% in heterozygous animals. In homozygous animals specific binding could only be detected after long-term film exposure (12 weeks). Regions exhibiting this residual [H-3]deltorphin I binding correlated significantly with those demonstrating high levels of the mu-receptor and were abolished in the presence of the mu-agonist DAMGO. Autoradiographic mapping showed significant overall reductions in [H-3]DAMGO and [H-3]CI-977 binding throughout the brain following loss of both copies of the Oprd1 gene. In contrast, overall levels of [H-3]bremazocine binding were higher in brains from -/- than +/+ mice. Our findings suggest that residual [H-3]deltorphin I binding in the brain of delta-receptor gene knockout mice is the result of cross-reactivity with mu-sites and that there are no delta-receptor subtypes derived from a different gene. Changes in mu- and kappa-receptor labeling suggest compensatory changes in these subtypes in response to the absence of the delta-receptor. The differences in [H-3]CI-977 and [H-3]bremazocine binding indicate these ligands show differential recognition of the kappa-receptor. (C) 2002 Elsevier Science B.V. All rights reserved.