Chen D C, Quock R M
Children's Hospital of Wisconsin, Milwaukee.
Anesth Prog. 1990 Jul;37(4):181-5.
This study was undertaken to assess the sensitivity of nitrous oxide (N2O) analgesia to antagonism by intrathecally (IT) and intracerebroventricularly (ICV) administered antagonists selective for kappa- and mu-opioid receptors. Male ICR mice were pretreated IT or ICV with the kappa antagonist nor-binaltorphimine (nor-BNI), 1 or 50 nmol, respectively, or distilled water (control), then exposed to N2O (50% or 75% in oxygen). Compared with IT control mice, IT nor-BNI-pretreated mice responded with significantly less analgesia. Compared with ICV control mice, ICV nor-BNI-pretreated mice also showed markedly reduced analgesic response. Other mice were pretreated IT or ICV with either the selective and irreversible mu antagonist beta-funaltrexamine (beta-FNA, 5.0 micrograms) or distilled water (control). When exposed to N2O 24 h later, beta-FNA-pretreated and control mice exhibited comparable analgesic responses. These preliminary results suggest that N2O analagesia in mice may involve spinal and supraspinal kappa-opioid receptors but not mu-opioid receptors.
本研究旨在评估一氧化二氮（N₂O）镇痛作用对鞘内（IT）和脑室内（ICV）注射的κ-阿片受体和μ-阿片受体选择性拮抗剂的拮抗敏感性。雄性ICR小鼠分别用1或50 nmol的κ-拮抗剂 nor-纳洛酮啡（nor-BNI）或蒸馏水（对照）进行鞘内或脑室内预处理，然后暴露于N₂O（氧气中50%或75%）。与鞘内对照小鼠相比，鞘内nor-BNI预处理的小鼠镇痛反应明显降低。与脑室内对照小鼠相比，脑室内nor-BNI预处理的小鼠镇痛反应也明显降低。其他小鼠分别用选择性不可逆μ-拮抗剂β-氟纳曲胺（β-FNA，5.0微克）或蒸馏水（对照）进行鞘内或脑室内预处理。24小时后暴露于N₂O时，β-FNA预处理的小鼠和对照小鼠表现出相当的镇痛反应。这些初步结果表明，小鼠中N₂O镇痛作用可能涉及脊髓和脊髓上的κ-阿片受体，而不涉及μ-阿片受体。
