Huang K H, Shyu B C
Acta Physiol Scand. 1987 Mar;129(3):401-6. doi: 10.1111/j.1748-1716.1987.tb08084.x.
In the present study tail-flick latency (TFL) and squeak threshold (ST) were investigated in different environmental conditions in normotensive Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The TFL did not vary significantly during the testing period (120 min). The ST increased gradually and significantly with time when measured in rats restrained in the TFL test tube. Freely moving rats transferred to the TFL test tube showed a marked decrease of the ST. During the stay in the TFL test tube, the ST value increased gradually. Also after transfer from the test tube to the home cage the threshold increased to the same level as freely moving rats. There were no significant differences in these effects between WKY and SHR. Naloxone (1 mg kg-1 i.v.) decreased the ST in both freely moving and restrained animals of either strain. Intravenous injection of morphine (mg kg-1) gave a pronounced threshold increase of ST in both groups. It is suggested that animals restrained in the TFL test tube become hyperalgesic. The adaptation to stress is reflected in the ST but not in the TFL. Squeak threshold appears to be influenced by a tonically active endorphin system.
在本研究中，对正常血压的Wistar Kyoto大鼠（WKY）和自发性高血压大鼠（SHR）在不同环境条件下的甩尾潜伏期（TFL）和鸣叫阈值（ST）进行了研究。在测试期间（120分钟），TFL没有显著变化。当在TFL测试管中对大鼠进行测量时，ST随时间逐渐且显著增加。转移到TFL测试管中的自由活动大鼠的ST显著降低。在TFL测试管中停留期间，ST值逐渐增加。从测试管转移到饲养笼后，阈值也增加到与自由活动大鼠相同的水平。WKY和SHR在这些效应上没有显著差异。纳洛酮（1毫克/千克静脉注射）可降低两种品系自由活动和受限制动物的ST。静脉注射吗啡（毫克/千克）可使两组的ST阈值显著升高。提示在TFL测试管中受限制的动物会出现痛觉过敏。对应激的适应反映在ST上，而不是TFL上。鸣叫阈值似乎受持续活跃的内啡肽系统影响。
