Bansinath M, Ramabadran K, Turndorf H, Puig M M
Department of Anesthesiology, School of Medicine, New York University Medical Center, NY 10016.
Pharmacol Biochem Behav. 1989 Jun;33(2):459-63. doi: 10.1016/0091-3057(89)90530-3.
The effects of yohimbine (0.1, 1, 3 and 10 mg/kg SC) on nociceptive threshold were tested in mice using the tail-immersion and hot-plate tests. The tail-flick (withdrawal) latency, a monosynaptic spinal nociceptive response, was significantly lowered by yohimbine. This hyperalgesic response was at its peak 0.5 hr after yohimbine injection. The tail-flick latencies expressed as % of basal latencies were, 95 +/- 8, 100 +/- 10, 62 +/- 10, 33 +/- 7 and 28 +/- 4 in vehicle and 0.1, 1, 3 and 10 mg/kg in yohimbine-treated groups respectively. Yohimbine-induced hyperalgesia was observed when stimulus temperature was either 50 degrees C or 45 degrees C; however, the opiate antagonist naloxone (3 mg/kg SC) induced a hyperalgesic response at 50 degrees C and an analgesic response at 45 degrees C stimulus temperature. Streptozotocin-induced hyperglycemia did not influence the hyperalgesic response of yohimbine. In the hot-plate (60 degrees C) test, which involves higher centers and a polysynaptic nociceptive reflex, yohimbine did not modify the jump latency. The data provide evidence for the presence of a tonic spinal noradrenergic inhibitory control of nociceptive mechanism(s) which does not appear to be readily altered by hyperglycemia.
使用尾部浸入法和热板试验，在小鼠中测试了育亨宾（0.1、1、3和10mg/kg，皮下注射）对伤害性感受阈值的影响。尾部甩动（撤离）潜伏期是一种单突触脊髓伤害性感受反应，育亨宾使其显著缩短。这种痛觉过敏反应在育亨宾注射后0.5小时达到峰值。以基础潜伏期的百分比表示的尾部甩动潜伏期，在溶剂对照组中为95±8，在育亨宾处理组中，0.1mg/kg、1mg/kg、3mg/kg和10mg/kg剂量组分别为100±10、62±10、33±7和28±4。当刺激温度为50℃或45℃时，均可观察到育亨宾诱导的痛觉过敏；然而，阿片类拮抗剂纳洛酮（3mg/kg，皮下注射）在50℃刺激温度下诱导痛觉过敏反应，在45℃刺激温度下诱导镇痛反应。链脲佐菌素诱导的高血糖并未影响育亨宾的痛觉过敏反应。在涉及高级中枢和多突触伤害性感受反射的热板（60℃）试验中，育亨宾并未改变跳跃潜伏期。这些数据为存在一种对伤害性感受机制的紧张性脊髓去甲肾上腺素能抑制控制提供了证据，这种控制似乎不易被高血糖改变。
