Lai H, Carino M
Department of Bioengineering, University of Washington, Seattle 98195-7962, USA.
Bioelectromagnetics. 1998;19(7):432-7.
In previous research, we have found that acute exposure to a 60 Hz magnetic field decreased cholinergic activity in the frontal cortex and hippocampus of the rat as measured by sodium-dependent high-affinity choline uptake activity. We concluded that the effect was mediated by endogenous opioids inside the brain because it could be blocked by pretreatment of rats before magnetic field exposure with the opiate antagonist naltrexone, but not by the peripheral antagonist naloxone methiodide. In the present study, the involvement of opiate receptor subtypes was investigated. Rats were pretreated by intracerebroventricular injection of the mu-opiate receptor antagonist, beta-funaltrexamine, or the delta-opiate receptor antagonist, naltrindole, before exposure to a 60 Hz magnetic field (2 mT, 1 hour). It was found that the effects of magnetic field on high-affinity choline uptake in the frontal cortex and hippocampus were blocked by the drug treatments. These data indicate that both mu- and delta-opiate receptors in the brain are involved in the magnetic field-induced decreases in cholinergic activity in the frontal cortex and hippocampus of the rat.
在先前的研究中，我们发现，通过钠依赖性高亲和力胆碱摄取活性测定，急性暴露于60赫兹磁场会降低大鼠额叶皮质和海马体中的胆碱能活性。我们得出结论，该效应是由脑内的内源性阿片类物质介导的，因为在用阿片类拮抗剂纳曲酮对大鼠进行磁场暴露前预处理可阻断该效应，但外周拮抗剂甲硫氨酸纳洛酮则不能。在本研究中，对阿片受体亚型的参与情况进行了研究。在暴露于60赫兹磁场（2毫特斯拉，1小时）之前，通过脑室内注射μ-阿片受体拮抗剂β-芬氟拉明或δ-阿片受体拮抗剂纳曲吲哚对大鼠进行预处理。结果发现，药物处理可阻断磁场对额叶皮质和海马体中高亲和力胆碱摄取的影响。这些数据表明，脑内的μ-和δ-阿片受体均参与了磁场诱导的大鼠额叶皮质和海马体胆碱能活性降低。
