Stevens C W, Pezalla P D, Yaksh T L
Brain Res. 1987 Jan 27;402(1):201-3. doi: 10.1016/0006-8993(87)91069-9.
Spinal administration of low doses of dynorphin, beta-endorphin or Met-enkephalin produces a potent, dose-dependent increase in the nociceptive threshold in the unanesthetized frog, Rana pipiens. Nociceptive thresholds were determined by using the acetic acid test, previously shown to be a sensitive indicator of antinociception in this amphibian species. Of particular interest, spinally administered dynorphin produces a potent antinociception in frogs without any signs of motor dysfunction seen after spinally administered dynorphin in mammalian species.
向未麻醉的豹蛙脊髓注射低剂量的强啡肽、β-内啡肽或甲硫氨酸脑啡肽，会使其伤害性感受阈值产生显著的、剂量依赖性的升高。伤害性感受阈值通过乙酸试验来测定，该试验先前已被证明是这种两栖动物抗伤害感受的敏感指标。特别值得注意的是，向蛙脊髓注射强啡肽会产生显著的抗伤害感受作用，且没有出现像在哺乳动物中脊髓注射强啡肽后所见到的任何运动功能障碍迹象。
