Tateyama Shingo, Ikeda Tetsuya, Kosai Kazuko, Nakamura Tadashi, Kasaba Toshiharu, Takasaki Mayumi, Nishimori Toshikazu
Department of Anesthesiology, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
Eur J Pharmacol. 2002 Sep 6;451(1):79-87. doi: 10.1016/s0014-2999(02)02196-9.
We evaluated the potency of endomorphin-1 and -2 as endogenous ligands on c-Fos and Zif/268 expression in the spinal dorsal horn by formalin injection to the rat hind paw. Endomorphin-1, -2, or morphine was administered intrathecally or intracerebroventricularly 5 min before formalin injection (5%, 100 microl). All drugs produced marked reductions of formalin-induced c-Fos and Zif/268 immunoreactivity in laminae I and II, and laminae V and VI in the rat lumbar spinal cord. The reductions of Zif/268 expression by endomorphins were greater than those by morphine, while the reductions of c-Fos expression by endomorphins were smaller than those by morphine. These effects of endomorphins were attenuated by pretreatment with naloxone. These results indicate that endomorphin-1 and -2 act as endogenous ligands of mu-opioid receptor in neurons of the spinal dorsal horn and suppress the processing of nociceptive information in the central nervous system.
我们通过向大鼠后爪注射福尔马林，评估了内吗啡肽-1和-2作为内源性配体对脊髓背角中c-Fos和Zif/268表达的作用。在福尔马林注射（5%，100微升）前5分钟，经鞘内或脑室内给予内吗啡肽-1、-2或吗啡。所有药物均使大鼠腰段脊髓I层和II层以及V层和VI层中福尔马林诱导的c-Fos和Zif/268免疫反应性显著降低。内吗啡肽对Zif/268表达的降低作用大于吗啡，而内吗啡肽对c-Fos表达的降低作用小于吗啡。内吗啡肽的这些作用可被纳洛酮预处理减弱。这些结果表明，内吗啡肽-1和-2作为脊髓背角神经元中μ-阿片受体的内源性配体，抑制中枢神经系统中伤害性信息的处理。
