Stevens C W, Pezalla P D
Brain Res. 1984 May 28;301(1):171-4. doi: 10.1016/0006-8993(84)90418-9.
Intraspinal injection of levorphanol (3 micrograms) at the lumbar area of the leopard frog, Rana pipiens, induced analgesia which was completely blocked by co-injection of naloxone (3 micrograms), whereas dextrorphan (3 micrograms) induced analgesia which was unaffected by naloxone. Subcutaneous levorphanol (20 or 80 mg/kg) induced a dose-dependent analgesia which was blocked by concurrent naloxone (2 mg/kg), while only the higher dose of dextrorphan (80 mg/kg) induced analgesia which was unaffected by concurrent naloxone at 8 or 80 mg/kg. These data are the first to indicate naloxone-insensitive, dextrorphan-induced analgesia.
在豹蛙（北美豹蛙）腰椎区域脊髓内注射左啡诺（3微克）可诱导产生镇痛作用，而同时注射纳洛酮（3微克）可完全阻断该镇痛作用；相反，右啡烷（3微克）诱导产生的镇痛作用不受纳洛酮影响。皮下注射左啡诺（20或80毫克/千克）可诱导产生剂量依赖性镇痛作用，同时注射纳洛酮（2毫克/千克）可阻断该作用；而只有较高剂量的右啡烷（80毫克/千克）诱导产生的镇痛作用不受同时注射的8或80毫克/千克纳洛酮的影响。这些数据首次表明了右啡烷诱导产生的纳洛酮不敏感的镇痛作用。
