强啡肽对脊髓损伤后兴奋性氨基酸含量变化的影响与意义

Effect and significance of dynorphin on changes of excitatory amino acid after spinal cord injury in rats

为阐明脊髓损伤后病理因于强啡肽（Dyn）与兴奋性氨基酸（EAA）的关系，通过蛛网膜下腹内插管，在伤后20min给予不同剂量、不同种类Dyn，应用高效液相分析技术测定大鼠脊髓损伤后伤段脊髓组织中EAA含量的动态变化。结果显示，DunA使脊髓组织EAA含量显著增加，其增加的量和持续时间与DynA剂量有关，且有剂量依赖性，但不受阿片受体拮抗剂影响。相同剂量的非阿片受体激动剂DynA2－17和阿片受体激动剂DynA1-17对脊髓EAA的改变相似，DnyA1-8也产生显著的EAA改变，但程度较小。本实验结果对Dyn的病理作用包括非阿片受体途径的学说提供了进一步的支持，在非阿片途径中EAA的作用可能是最重要的。

To understand the relation of dynorphins and excitatory amino acid (EAA) as pathophysiological factors in spinal cord injury,regional concentrations of EAA were assessed with high-performance liquid chromatography after intrathecall administration of various kinds and dosage of dynorphin in rats, 20min posttrauma. The results showed dynorphin induced EAA elevation significantly. The degree and duration of elevation of these EAA were dose dependent but not modlfied by the opioid receptor antagonist nalmefene. In comparable doses, dynorphin A2-17, which is inactive at the opioid receptor,produced similar alterations in EAA as dynorphin A1-17, whereas dynorphin A1- 8 caused significantly smaller changes. The present observations provide further support for the concept that dynorphin' s pathophysiologic effects may include non-opioid actions,in which EAA's effect may be the most important.