Orally Active Opioid <i>μ</i>/<i>δ</i> Dual Agonist MGM-16, a Derivative of the Indole Alkaloid Mitragynine, Exhibits Potent Antiallodynic Effect on Neuropathic Pain in Mice
作者:Kenjiro Matsumoto、Minoru Narita、Naotaka Muramatsu、Terumi Nakayama、Kaori Misawa、Mariko Kitajima、Kimihito Tashima、Lakshmi A. Devi、Tsutomu Suzuki、Hiromitsu Takayama、Syunji Horie
DOI:10.1124/jpet.113.208108
日期:2014.3
( E )-Methyl 2-((2 S ,3 S ,7 aS ,12b S )-3-ethyl-7 a -hydroxy-8-methoxy-1,2,3,4,6,7,7 a ,12 b -octahydroindolo[2,3- a ]quinolizin-2-yl)-3-methoxyacrylate (7-hydroxymitragynine), a main active constituent of the traditional herbal medicine Mitragyna speciosa , is an indole alkaloid that is structurally different from morphine. 7-Hydroxymitragynine induces a potent antinociceptive effect on mouse acute pain through μ -opioid receptors. In this study, we developed dual-acting μ - and δ -opioid agonists MGM-15 and MGM-16 from 7-hydroxymitragynine for the treatment of acute and chronic pain. MGM-16 showed a higher potency than that of 7-hydroxymitragynine and MGM-15 in in vitro and in vivo assays. MGM-16 exhibited a high affinity for μ - and δ -opioid receptors, with K i values of 2.1 and 7.0 nM, respectively. MGM-16 showed μ - and δ -opioid full agonistic effects in a guanosine 5′- O -(3-[35S]thiotriphosphate) binding assay and in a functional test using electrically elicited guinea pig ileum and mouse vas deferens contractions. Systemic administration of MGM-16 produced antinociceptive effects in a mouse acute pain model and antiallodynic effects in a chronic pain model. The antinociceptive effect of MGM-16 was approximately 240 times more potent than that of morphine in a mouse tail-flick test, and its antiallodynic effect was approximately 100 times more potent than that of gabapentin in partial sciatic nerve-ligated mice, especially with oral administration. The antinociceptive effect of MGM-16 was completely and partially blocked by the μ -selective antagonist β -funaltrexamine hydrochloride ( β -FNA) and by the δ -selective antagonist naltrindole, respectively, in a tail-flick test. The antiallodynic effect of MGM-16 was completely blocked by β -FNA and naltrindole in a neuropathic pain model. These findings suggest that MGM-16 could become a class of a compound with potential therapeutic utility for treating neuropathic pain.
( E )-Methyl 2-((2 S ,3 S ,7 aS ,12b S )-3-ethyl-7 a -hydroxy-8-methoxy-1,2,3,4,6,7,7 a ,12 b -octahydroindolo[2,3- a ]quinolizin-2-yl)-3-methoxyacrylate (7-hydroxymitragynine)、是一种吲哚生物碱,在结构上与吗啡不同。7-Hydroxymitragynine 可通过 μ -opioid 受体对小鼠急性疼痛产生强效抗痛作用。在这项研究中,我们从 7-hydroxymitragynine 中开发出了μ - 和 δ - 阿片受体双效激动剂 MGM-15 和 MGM-16,用于治疗急性和慢性疼痛。在体外和体内试验中,MGM-16 的效力高于 7-hydroxymitragynine 和 MGM-15。MGM-16 对 μ - 和 δ - 阿片受体具有很高的亲和力,K i 值分别为 2.1 和 7.0 nM。在鸟苷 5′- O -(3-[35S]硫代磷酸)结合试验和电诱导豚鼠回肠和小鼠输精管收缩的功能测试中,MGM-16 显示出 μ - 和 δ - 阿片受体的完全激动作用。在小鼠急性疼痛模型中,全身给药 MGM-16 可产生抗痛觉效应;在慢性疼痛模型中,MGM-16 可产生抗神经痛效应。在小鼠尾叩试验中,MGM-16 的抗痛觉作用比吗啡强约 240 倍;在部分坐骨神经结扎的小鼠中,MGM-16 的抗痛觉作用比加巴喷丁强约 100 倍,尤其是在口服给药的情况下。在尾叩试验中,MGM-16 的抗痛觉作用分别被 μ 选择性拮抗剂 β -funaltrexamine hydrochloride ( β -FNA) 和 δ 选择性拮抗剂 naltrindole 完全和部分阻断。在神经病理性疼痛模型中,MGM-16 的镇痛作用被 β -FNA 和纳吲哚完全阻断。这些研究结果表明,MGM-16 可成为一类具有潜在治疗作用的化合物,用于治疗神经病理性疼痛。