Pharmacology and physiology of pregnancy induced analgesia.

妊娠镇痛是麻醉学家感兴趣的，因为观察到产妇可能需要较少的麻醉或镇痛药物。这是一系列研究大鼠妊娠镇痛药理学的实验之一。在妊娠动物中，在妊娠第21天证明了甩尾潜伏期（TFL）的显著增加。鞘内注射氯胺酮（50和100 μ g）在妊娠第21天产生剂量依赖性TFL延长。然而，在妊娠第7天和第17天以及产后第7天，未观察到注射氯胺酮后TFL的这种增强作用（图1）。在妊娠第21天观察到氯胺酮给药后AUC增加的相似模式。本研究的主要发现是，鞘内注射氯胺酮增强了妊娠晚期对热伤害性刺激的妊娠诱导镇痛程度。这些结果表明，由于与内源性阿片系统的相互作用，氯胺酮的协同抗伤害性作用，这是只在妊娠后期激活。（Journal of Anesthesia 13：74：1999，Anesthesiology 91：A778：1999）。

Pregnancy-induced analgesia is of interest to anesthesiologists because of the observation that parturients may require less anesthetic or analgesic drugs. This is one of series of experiments to examine the pharmacology of pregnancy-induced analgesia in rats.In pregnant animals, a significant increase in tail-flick latency(TFL) was demonstrated on day 21 of gestation. Intrathecally administered ketamine (50 and 100 microg) produced a dose dependent prolongation of TFL on day 21 of gestation. However, this potentiative effect in TFL after ketamine injection were not observed on days 7 and 17 of gestation , and post-partum day 7 (Fig 1). A similar pattern of augmentation in AUC after ketamine was observed on day 21 of gestation. The main finding of this study was that intrathecally administered ketamine potentiated the degree of pregnant-induced analgesia to thermal noxious stimulation late in pregnancy. These results suggest a synergistic antinociceptive effect of ketamine due to an interaction with an endogenous opiate system that is only activated late in pregnancy. (Journal of Anesthesia 13:74:1999 , Anesthesiology 91:A778:1999).