Lee C E, Kest B, Jenab S, Inturrisi C E
Department of Pharmacology, Cornell University Medical College, New York, NY 10021, USA.
Brain Res Mol Brain Res. 1997 Aug;48(1):17-22. doi: 10.1016/s0169-328x(97)00054-5.
Studies in vivo demonstrate that antisense oligodeoxynucleotide (ODN) treatment specifically reduces the functions mediated by numerous central nervous system (CNS) receptors, including opioid receptors. However, the effects of antisense ODN on the opioid receptor mRNA target, itself are rarely examined. In the present study, the effect of supraspinal antisense ODN administration on delta-opioid receptor (DOR) mRNA levels in selected CNS regions, was investigated in mice. ODN targeting a 20-nucleotide sequence of the DOR mRNA transcript was administered by intracerebroventricular (i.c.v.) injection twice daily for 3 days. First, to confirm that antisense ODN treatment decreases DOR function in this system, antinociception produced by DOR-selective agonist [D-Ala2]deltorphin II was assessed on day 4. A 2-fold reduction in [D-Ala2]deltorphin II potency was revealed in antisense ODN-treated mice compared to mice receiving control treatments. DOR mRNA levels in selected CNS regions which either mediate antinociception; medial thalamus (MThal), periaqueductal gray (PAG), frontal cortex (FCtx) and spinal cord (SpC) or exhibit relatively high levels of DOR mRNA; nucleus accumbens (Acb) and caudate-putamen (CPu) were then quantitated by solution hybridization. Levels of DOR mRNA in antisense ODN-treated mice were not different from levels in mice treated with saline vehicle, which ranged from 0.07 pg/microg total RNA in MThal and PAG to 0.26 pg/microg total RNA in CPu. These results are both consistent with previous reports that antisense oligodeoxynucleotide (ODN) treatment down-regulates DOR protein in vivo and indicate that this down-regulation is not associated with altered DOR mRNA levels.
体内研究表明，反义寡脱氧核苷酸（ODN）治疗可特异性降低包括阿片受体在内的多种中枢神经系统（CNS）受体介导的功能。然而，反义ODN对阿片受体mRNA靶点本身的影响却鲜有研究。在本研究中，研究了小鼠脑室内注射反义ODN对选定CNS区域中δ-阿片受体（DOR）mRNA水平的影响。针对DOR mRNA转录本20个核苷酸序列的ODN通过脑室内（i.c.v.）注射给药，每天两次，共3天。首先，为了证实反义ODN治疗可降低该系统中DOR的功能，在第4天评估了DOR选择性激动剂[D-Ala2]deltorphin II产生的抗伤害感受作用。与接受对照治疗的小鼠相比，反义ODN治疗的小鼠中[D-Ala2]deltorphin II的效力降低了2倍。然后通过溶液杂交对选定的CNS区域中DOR mRNA的水平进行定量，这些区域要么介导抗伤害感受作用，即内侧丘脑（MThal）、导水管周围灰质（PAG）、额叶皮质（FCtx）和脊髓（SpC），要么表现出相对较高水平的DOR mRNA，即伏隔核（Acb）和尾状核-壳核（CPu）。反义ODN治疗的小鼠中DOR mRNA的水平与用生理盐水载体治疗的小鼠中的水平没有差异，生理盐水载体治疗的小鼠中DOR mRNA水平范围为MThal和PAG中每微克总RNA含0.07 pg至CPu中每微克总RNA含0.26 pg。这些结果既与先前关于反义寡脱氧核苷酸（ODN）治疗在体内下调DOR蛋白的报道一致，又表明这种下调与DOR mRNA水平的改变无关。
