一种新的阿片肽对小鼠脑和小肠组织阿片受体和肽转运载体基因的影响

Effect of a new opioid peptide on opioid receptor and peptide transporter gene of brain and small intestinal tissues in mice

目的:从转录水平研究一种新的外源阿片肽 YPFPGPIRYG经胃肠道途径对小鼠脑组织和小肠组织阿片受体和肽转运载体基因的影响．方法:24只小鼠随机分为阿片肽样品组n= 12)和对照组(n=12),在饮水中分别添加浓度为8×10-7mol/L的阿片肽样品YPFPGPIRYG 和双蒸水(空白对照组),小鼠连续饮用2 wk．提取受试小鼠脑组织和小肠组织的总RNA, RT-PCR检测μ阿片受体、δ阿片受体和肽转运载体PepT1 mRNA的变化情况．结果:小鼠的脑组织中同时有μ阿片受体和δ阿片受体mRNA的表达,但阿片肽组小鼠与对照组相比,脑组织中μ阿片受体和δ阿片受体 mRNA的丰度没有变化;小鼠的小肠中同时有μ阿片受体、δ阿片受体和肽转运载体PepT1 mRNA的表达,且阿片肽组小鼠小肠中的μ阿片受体和δ阿片受体mRNA的表达与对照组相比明显上调(P<0．05),而肽转运载体PepT1 mRNA的丰度与对照组相比没有差异．结论:小鼠组织中不同阿片受体的表达存在明显的组织特异性,阿片肽YPFPGPIRYG对小鼠的生理调节不是通过与中枢神经系统上的阿片受体结合发挥作用,其可能与小肠上的δ和μ阿片受体结合发挥作用．

AIM： To investigate the effect of a new opioid peptide, YPFPGPIRYG, on the opioid receptor and peptide transporter gene of brain and small intestinal tissues via gastrointestinal tracts at transcription level. METHOOS： Twenty-four mice were randomly divided into opioid group （n = 12） and control group （n = 12）, which were fed with 8×10^7 mol/ L YPFPGPIRYG and double distilled water, respectively, for 2 wk. The total RNA was extracted from the brain and small intestinal tissues of mice for the detection of μ-, δ-opioid receptor and peptide transporters PepT1 gene expression by reverse transcription-polymerase chain reaction （RT-PCR）. RESULTS： In the brain and small intestinal tissues, μ- and δ-opioid receptor transcripts were detected, while peptide transporter PepT1 was only found to be expressed in the small intestine. In comparison with those in the controls, the ex- pression of μ- and δ-opioid receptor were significantly enhanced in the small intestine （P 〈 0.05）, but not in the brain, and PepT1 gene expression was not changed in the intestinal tissues of mice treated with YPFPGPIRYG. CONCLUSION： Opioid receptor expression has tissue specificity. The immunomodulatory effects of opioid YPFPGPIRYG do not attribute to the interaction with the opioid receptors in central nervous system （CNS）, but with δ- and μ-opioid receptor in small intestine.