实验采用辐射热作为伤害性刺激，以浅麻状态下大鼠甩尾潜伏期为痛阈指标，观察了侧脑室微量注射硝普钠及注射硝普钠与血红蛋白混合液对大鼠痛阈的影响。结果表明，选用１ｍｇ／ｍｌ硝普钠，注入后即刻甩尾潜伏期有明显缩短，２ｍｉｎ达高峰（３６２％，Ｐ＜００５）；以硝普钠与血红蛋白的混合液（１∶６５ｍｇ／ｍｌ）注入，甩尾潜伏期无显著变化。提示：硝普钠在高位中枢对伤害性刺激有易化作用，其作用是通过一氧化氮实现的。 Radiation heat was used as the nociceptive stimulus. The latency of tail flick in shallow hemp as index of pain threshold was observed. Effects of microinjection of sodium nitroprusside into the lateral ventricle and injection of sodium nitroprusside and hemoglobin on the pain threshold were observed. The results showed that 1 mg / ml sodium nitroprusside was used to induce tail flick latency shortly after injection, reaching the peak at 2 minutes (362%, P <005). With a mixture of sodium nitroprusside and hemoglobin  5mg / ml) injection, tail flick latency no significant change. Tip: sodium nitroprusside in the high center of noxious stimuli to ease the role of its role through the nitric oxide.