Lai H, Horita A, Chou C K, Guy A W
Department of Pharmacology, University of Washington School of Medicine, Seattle 98195.
Pharmacol Biochem Behav. 1987 Aug;27(4):635-9. doi: 10.1016/0091-3057(87)90186-9.
In previous research, we found that sodium-dependent high-affinity choline uptake in the hippocampus and frontal cortex of the rat was lowered after acute (45 min) exposure to low-level 2450-MHz pulsed microwaves (power density 1 mW/cm2; average whole body specific absorption rate, 0.6 W/kg; 2 mu sec pulses, 500 pps). In the present experiment, we investigated developments of tolerance and classical conditioning to these effects of microwaves. Rats were exposed to microwaves in cylindrical waveguides in 10 daily sessions (45 min per session). In an 11th session, we subjected the rats to either microwave (study of tolerance) or sham exposure (study of conditioned effect) for 45 min, and immediately measured choline uptake in the hippocampus and frontal cortex. We found that tolerance, a decrease in response to microwaves, developed to the effect of microwaves on choline uptake in the hippocampus, but not in the frontal cortex. Conditioned effects were also observed: an increase in choline uptake in the hippocampus and a decrease in uptake in the frontal cortex. These data suggest that the effects of microwaves on choline uptake in the hippocampus and frontal cortex are classically conditionable, probably to cues in the exposure environment.
在先前的研究中，我们发现，大鼠急性（45分钟）暴露于低强度2450兆赫脉冲微波（功率密度1毫瓦/平方厘米；全身平均比吸收率0.6瓦/千克；2微秒脉冲，500次/秒）后，海马体和额叶皮质中钠依赖性高亲和力胆碱摄取降低。在本实验中，我们研究了对微波这些效应的耐受性发展情况以及经典条件反射。大鼠每天在圆柱形波导中暴露于微波下，共进行10次（每次45分钟）。在第11次实验中，我们让大鼠接受45分钟的微波照射（耐受性研究）或假照射（条件效应研究），并立即测量海马体和额叶皮质中的胆碱摄取。我们发现，对微波对海马体中胆碱摄取的影响产生了耐受性，即对微波的反应降低，但额叶皮质中未出现这种情况。还观察到了条件效应：海马体中胆碱摄取增加，额叶皮质中摄取减少。这些数据表明，微波对海马体和额叶皮质中胆碱摄取的影响可形成经典条件反射，可能是对暴露环境中的线索产生条件反射。
