Heyliger S O, Goodman C B, Ngong J M, Soliman K F
College of Pharmacy and Pharmaceutical Sciences, Florida A & M University, Tallahassee, FL 32307, USA.
Pharmacol Res. 1998 Oct;38(4):243-50. doi: 10.1006/phrs.1998.0362.
Male Sprague-Dawley rats weighing 150-200 g were given doses of tryptophan methyl ester or its metabolites; kynurenine sulphate, kynurenic acid, xanthurenic acid, quinolinic acid, anthranilic acid methyl ester or picolinic acid methyl ester. Doses administered intraperitoneally were 50, 100, 200, 300, 400 and 600 mg kg-1. Pain sensitivity was assessed using the hotplate and tailflick methods at 30 min before and at 30-min interval after the injection of test compounds. The administrations of tryptophan, kynurenic acid, quinolinic acid, anthranilic acid, xanthurenic acid, picolinic acid, and kynurenine were associated with analgesia. Animals given 300 or 600 mg kg-1 of tryptophan exhibited a significant decrease (P<0.05; P<0.01, respectively) in pain sensitivity with the hotplate test. l-Kynurenic acid (300 mg kg-1) produced analgesia (P<0.01) 30 min after drug administration. Quinolinic and anthranilic acids both produced prolonged decrease in pain sensitivity (P<0.05) using the tailflick test. These results indicate that tryptophan and some of its metabolites possess analgesic properties.
给体重150 - 200克的雄性斯普拉格-道利大鼠注射色氨酸甲酯或其代谢产物；硫酸犬尿氨酸、犬尿喹啉酸、黄尿酸、喹啉酸、邻氨基苯甲酸甲酯或吡啶甲酸甲酯。腹腔注射剂量为50、100、200、300、400和600毫克/千克。在注射受试化合物前30分钟及注射后每隔30分钟，使用热板法和甩尾法评估疼痛敏感性。色氨酸、犬尿喹啉酸、喹啉酸、邻氨基苯甲酸、黄尿酸、吡啶甲酸和犬尿氨酸的给药与镇痛作用相关。给予300或600毫克/千克色氨酸的动物在热板试验中疼痛敏感性显著降低（分别为P<0.05；P<0.01）。L-犬尿喹啉酸（300毫克/千克）在给药30分钟后产生镇痛作用（P<0.01）。使用甩尾试验，喹啉酸和邻氨基苯甲酸均使疼痛敏感性持续降低（P<0.05）。这些结果表明色氨酸及其一些代谢产物具有镇痛特性。
