Zagon I S, McLaughlin P
Department of Anatomy, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
Life Sci. 1988;43(16):1313-8. doi: 10.1016/0024-3205(88)90586-3.
Endogenous opioid systems (endogenous opioids and their receptors) are known to participate in the regulation of tumor growth. The present study was conducted to examine whether [Met5]-enkephalin influences the growth of transplanted neuroblastoma, and to explore the role of other opioid peptides in carcinogenesis. A/Jax mice were inoculated with 10(6) S20Y cells and received daily injections of [Met5]-enkephalin. Dosages of 0.5 to 30 mg/kg delayed tumor appearance and prolonged survival of these mice; antitumor effects were blocked by concomitant injections of naloxone. Daily administration (10 mg/kg) of [Leu5]-enkephalin had no effect on neurotumor growth. [D-Ala2, D-Leu5]-enkephalin and ethylketocyclazocine, ligands selective for delta and kappa receptors, respectively, also did not influence neuro-oncogenesis. These results demonstrated the potent growth inhibiting effects of the naturally occurring opioid pentapeptide, [Met5]-enkephalin, and substantiate reports identifying and characterizing an opioid receptor (i.e., zeta) for which [Met5]-enkephalin is the most potent ligand.
内源性阿片系统（内源性阿片及其受体）已知参与肿瘤生长的调节。本研究旨在探讨[Met5]-脑啡肽是否影响移植性神经母细胞瘤的生长，并探索其他阿片肽在致癌过程中的作用。将A/Jax小鼠接种10(6)个S20Y细胞，并每日注射[Met5]-脑啡肽。剂量为0.5至30mg/kg可延迟这些小鼠肿瘤的出现并延长其存活时间；同时注射纳洛酮可阻断抗肿瘤作用。每日给予（10mg/kg）[Leu5]-脑啡肽对神经肿瘤生长没有影响。分别对δ和κ受体具有选择性的配体[D-Ala2, D-Leu5]-脑啡肽和乙基酮环唑辛也不影响神经肿瘤发生。这些结果证明了天然存在的阿片五肽[Met5]-脑啡肽具有强大的生长抑制作用，并证实了有关鉴定和表征一种阿片受体（即ζ）的报道，[Met5]-脑啡肽是该受体最有效的配体。
