Medina V M, Wang L, Gintzler A R
Department of Biochemistry, State University of New York, Brooklyn 11203.
Brain Res. 1993 Sep 24;623(1):41-6. doi: 10.1016/0006-8993(93)90007-a.
In laboratory animals and humans, pregnancy is associated with opioid-mediated elevations in the threshold for responsiveness to aversive stimuli. Previous pharmacological analysis has demonstrated that this analgesia results, at least in part, from the activation of spinal cord kappa opioid receptors utilizing dynorphin as the major opioid substrate. The present report demonstrates that during late pregnancy, the content of spinal dynorphin A(1-17 and 1-8) is altered in a region-specific fashion. As a result, levels of dynorphin peptides are elevated, but only in the lumbar spinal region. In parturient animals, lumbar levels of dynorphin A(1-8) remained elevated but there was an additional increment in the content of dynorphin A(1-17). During late gestation, spinal content of Met-enkephalin and its precursor are also elevated, but, in contrast to dynorphin peptides, there is no interaction between condition and spinal level. Possible analgesic synergy between mu-delta and kappa opioid receptor systems is discussed. It is concluded that some parameter(s) of the pregnant condition triggers the activation of a spinal cord dynorphin system that attenuates the pain associated with late pregnancy and labor.
在实验动物和人类中，怀孕与阿片类物质介导的对厌恶刺激反应阈值升高有关。先前的药理学分析表明，这种镇痛作用至少部分是由于以强啡肽为主要阿片类底物激活脊髓κ阿片受体所致。本报告表明，在妊娠晚期，脊髓强啡肽A（1-17和1-8）的含量以区域特异性方式发生改变。结果，强啡肽肽水平升高，但仅在腰段脊髓区域。在分娩动物中，腰段强啡肽A（1-8）水平仍保持升高，但强啡肽A（1-17）的含量有额外增加。在妊娠晚期，甲硫氨酸脑啡肽及其前体的脊髓含量也升高，但与强啡肽肽不同，条件与脊髓水平之间没有相互作用。讨论了μ-δ和κ阿片受体系统之间可能的镇痛协同作用。得出的结论是，怀孕状态的某些参数触发了脊髓强啡肽系统的激活，该系统减轻了与妊娠晚期和分娩相关的疼痛。
