Dixon S J, Persinger M A
Behavioral Neuroscience Laboratory, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
Int J Neurosci. 2001 Aug;108(1-2):87-97. doi: 10.3109/00207450108986507.
In Experiment I, the nociceptive threshold for a criterion response to thermal stimuli (hot plate) for rats was obtained following injections with one of various dosages of either morphine or the nitric oxide synthase inhibitor, L-NAME. On the bases of these results, rats in Experiment II were injected with either morphine (4 mg/kg), L-NAME (50 mg/kg), both morphine and L-NAME, or saline after baseline measurements for nociception and then exposed to either a 1 microTesla magnetic field or to a sham field for 30 min. The magnetic field, presented once every 4 sec, was a frequency-modulated pattern whose pixel durations, for each of the 837 successive values, were 1 msec. Nociceptive thresholds were measured immediately after the exposure and 30 min later. The results indicated that exposure to this magnetic field abolished the analgesic effects of morphine or L-NAME when injected separately but not when injected together relative to rats that had received these drugs and had been exposed to the sham field.
在实验I中，给大鼠注射不同剂量的吗啡或一氧化氮合酶抑制剂L- NAME后，测定大鼠对热刺激（热板）产生标准反应的伤害性阈值。基于这些结果，在实验II中，对大鼠进行伤害感受基线测量后，分别注射吗啡（4毫克/千克）、L- NAME（50毫克/千克）、吗啡和L- NAME，或生理盐水，然后让它们暴露于1微特斯拉的磁场或假磁场中30分钟。磁场每4秒出现一次，是一种调频模式，其837个连续值中每个值的像素持续时间为1毫秒。在暴露后立即和30分钟后测量伤害性阈值。结果表明，相对于接受这些药物并暴露于假磁场的大鼠，暴露于该磁场会消除单独注射吗啡或L- NAME时的镇痛作用，但同时注射时则不会。
