Prato F S, Ossenkopp K P, Kavaliers M, Sestini E, Teskey G C
Magn Reson Imaging. 1987;5(1):9-14. doi: 10.1016/0730-725x(87)90478-4.
Exposure of adult male mice to a magnetic resonance imaging (MRI) procedure has been shown to abolish the nocturnal analgesic responses observed following treatment with morphine. The field component(s) responsible for this inhibitory effect were examined by exposing mice to either the static, time-varying or rf magnetic field components associated with an MRI procedure. In the middle of the night portion of their day-night cycle, mice were exposed for 23.2 min to one of the above field components, intraperitoneally injected with morphine sulphate (10 mg/kg) and then exposed to the field conditions for another 23.2 min, after which analgesic responses were determined. Analgesia was quantitated by determining the length of time mice were content to be on a hot surface (50 degrees C) before they showed discomfort by licking their paws. It was observed that the time-varying magnetic field completely abolished, the rf field significantly reduced, while the static field component (0.15 T) had no evident effect on morphine-induced analgesia. These results indicate that the time-varying, and to a lesser extent the rf, fields associated with the MRI procedure inhibit morphine-induced analgesia in mice. These data also raise the possibility that exposure in humans to some of the magnetic field components associated with MRI may have clinically relevant effects on the actions of narcotic drugs such as morphine.
成年雄性小鼠接受磁共振成像（MRI）检查后，其夜间对吗啡治疗产生的镇痛反应会消失。通过让小鼠分别暴露于与MRI检查相关的静磁场、时变磁场或射频磁场成分中，来研究导致这种抑制作用的磁场成分。在昼夜周期的午夜时段，将小鼠暴露于上述其中一种磁场成分中23.2分钟，腹腔注射硫酸吗啡（10毫克/千克），然后再将其暴露于该磁场环境中23.2分钟，之后测定镇痛反应。通过确定小鼠在热表面（50摄氏度）上保持舒适直至舔爪表示不适之前的时长来定量镇痛效果。结果发现，时变磁场完全消除了镇痛反应，射频磁场显著降低了镇痛反应，而静磁场成分（0.15特斯拉）对吗啡诱导的镇痛没有明显影响。这些结果表明，与MRI检查相关的时变磁场以及在较小程度上的射频磁场会抑制小鼠体内吗啡诱导的镇痛作用。这些数据还增加了一种可能性，即人类暴露于与MRI相关的某些磁场成分中可能会对吗啡等麻醉药物的作用产生临床相关影响。
