Itoh E, Hata T
Department of Pharmacology, Faculty of Pharmacy, Kinki University, Higashi-Osaka, Japan.
Jpn J Pharmacol. 1989 Oct;51(2):267-72. doi: 10.1254/jjp.51.267.
Neurotropin, a nonprotein component extracted from the skin of rabbits treated with vaccinia virus, has been clinically and experimentally reported to demonstrate analgesic effects. In this study, we investigated the antinociceptive action of neurotropin in relation to the serotonergic system, a pain inhibitory system, and substance P, a pain transmitter; we also attempted to determine whether it acts at the spinal or supraspinal level in mice. 1) The spinal cord (T6-T10) transection completely abolished the antinociceptive action of neurotropin, attenuated that of morphine, and had no influence on the action of clonidine. 2) The intrathecal substance P-induced behavior was inhibited by [D-Pro2, D-Trp7,9]-substance P, but not by neurotropin. 3) Preadministration of p-chlorophenylalanine or cyproheptadine inhibited the antinociceptive action of neurotropin. These data suggest that neurotropin does not directly act on pain transmitters at the spinal cord level, but acts at the supraspinal level, resulting in an inhibition of pain transmitter release at the spinal level by mediating pain inhibitory systems such as the serotonergic system in addition to the noradrenergic and GABAergic systems previously reported.
神经妥乐平是从接种牛痘病毒的兔皮肤中提取的一种非蛋白质成分，临床和实验报告均表明其具有镇痛作用。在本研究中，我们研究了神经妥乐平与5-羟色胺能系统（一种疼痛抑制系统）及P物质（一种疼痛递质）相关的抗伤害感受作用；我们还试图确定其在小鼠体内是作用于脊髓水平还是脊髓上水平。1）脊髓（T6-T10）横断完全消除了神经妥乐平的抗伤害感受作用，减弱了吗啡的抗伤害感受作用，而对可乐定的作用无影响。2）鞘内注射P物质诱导的行为受到[D-脯氨酸2，D-色氨酸7,9]-P物质的抑制，但不受神经妥乐平的抑制。3）预先给予对氯苯丙氨酸或赛庚啶可抑制神经妥乐平的抗伤害感受作用。这些数据表明，神经妥乐平并非直接作用于脊髓水平的疼痛递质，而是作用于脊髓上水平，通过介导诸如5-羟色胺能系统等疼痛抑制系统以及先前报道的去甲肾上腺素能和γ-氨基丁酸能系统，导致脊髓水平的疼痛递质释放受到抑制。
