Ishizuka Y, Oka T
Jpn J Pharmacol. 1984 Nov;36(3):397-405. doi: 10.1254/jjp.36.397.
Effects of 5'-guanylylimidodiphosphate (Gpp(NH)p) and sodium on the inhibition by various opioids of [3H]-naloxone binding to guinea-pig brain membrane preparations were studied. The ratio of the concentration required to produce a 50% inhibition of [3H]-naloxone binding in the presence of both Gpp(NH)p and sodium to that in the absence of both Gpp(NH)p and sodium (IC50 ratio) was less than 1 for antagonists, from 3 to 10 for mixed agonist-antagonists, from 16 to 85 for either kappa, delta, or peptide mu agonists, and more than 200 for morphine-like nonpeptide mu agonists. Exceptionally, the IC50 ratio of N,N-diallyl-[D-Ala2,D-Leu5]-enkephalin, an opioid which had been shown not to have an agonist activity in guinea-pig ileum but to have a naloxone-reversible agonist activity in mouse vas deferens, was less than 1. The significance of the different IC50 ratio among opioids employed in the present study was discussed.
研究了5'-鸟苷酰亚胺二磷酸（Gpp(NH)p）和钠对各种阿片类药物抑制[3H]-纳洛酮与豚鼠脑膜制剂结合的影响。在同时存在Gpp(NH)p和钠的情况下产生50%[3H]-纳洛酮结合抑制所需的浓度与在不存在Gpp(NH)p和钠的情况下所需浓度的比值（IC50比值），拮抗剂小于1，混合激动剂-拮抗剂为3至10，κ、δ或肽类μ激动剂为16至85，吗啡样非肽类μ激动剂大于200。例外的是，N,N-二烯丙基-[D-Ala2,D-Leu5]-脑啡肽（一种在豚鼠回肠中无激动剂活性但在小鼠输精管中有纳洛酮可逆激动剂活性的阿片类药物）的IC50比值小于1。讨论了本研究中使用的阿片类药物之间不同IC50比值的意义。
