Unterwald E M, Rubenfeld J M, Imai Y, Wang J B, Uhl G R, Kreek M J
Laboratory of the Biology of Addictive Diseases, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Brain Res Mol Brain Res. 1995 Nov;33(2):351-5. doi: 10.1016/0169-328x(95)00143-g.
Chronic administration of opioid antagonists has been shown to increase radioligand binding to brain opioid receptors. The present study was conducted to determine whether chronic exposure to the opioid antagonist naltrexone would similarly increase mu opioid receptor gene expression as measured by mRNA levels. Male Sprague-Dawley rats were administered naltrexone, 7-8 mg/kg/day, or saline by osmotic minipumps for 7 days. As expected, the density of mu opioid receptor binding sites was significantly higher in the brains of animals treated chronically with naltrexone as compared with saline-treated control animals. However, mu opioid receptor mRNA content determined by a solution hybridization RNase protection assay was not significantly altered in any brain region investigated. These results indicate that the upregulation of mu opioid receptors as measured by radioligand binding is not accompanied by increased levels of mu receptor mRNA.
长期给予阿片类拮抗剂已被证明会增加放射性配体与脑阿片受体的结合。本研究旨在确定长期暴露于阿片类拮抗剂纳曲酮是否会类似地增加通过mRNA水平测量的μ阿片受体基因表达。通过渗透微型泵给雄性Sprague-Dawley大鼠注射纳曲酮（7-8毫克/千克/天）或生理盐水，持续7天。正如预期的那样，与生理盐水处理的对照动物相比，长期用纳曲酮处理的动物大脑中μ阿片受体结合位点的密度显著更高。然而，通过溶液杂交核糖核酸酶保护试验测定的μ阿片受体mRNA含量在任何研究的脑区均未发生显著改变。这些结果表明，通过放射性配体结合测量的μ阿片受体上调并不伴随着μ受体mRNA水平的增加。
