Mathur Rashmi
Neurophysiology Laboratory, Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
Electromagn Biol Med. 2008;27(3):266-76. doi: 10.1080/15368370802304155.
There are several reports of altered pain sensation after exposure (from a few minutes to hours in single or repeated doses for 2-3 weeks) to electromagnetic fields (EMF) in adults. The commonly utilized noxious stimulus is radiant heat. The nociceptive responses are known to be influenced by characteristics of stimulus, organism, and environment. We studied the pattern of nociceptive responses to various noxious stimuli in growing rats exposed to radiofrequency field (73.5 MHz amplitude modulated, 16 Hz power density 1.33 mw/cm(2), SAR = 0.4 w/kg) for 45 d (2 h/d). Threshold current for stimulation of nociceptive afferents to mediate motor response of tail (TF), vocalization during stimulus (VD), and vocalization after discharge (VA); the withdrawal latency of tail (TFL) and hind paw (HPL) to thermal noxious stimulus and tonic pain responses were recorded in every rat. The TFL was not affected, HPL was decreased (p < 0.01), and the thresholds of TF and VD were not affected, while, that of VA was significantly decreased. The tonic pain rating was decreased (p < 0.01). A decrease in the threshold of VA (p < 0.01) is indicative of an increase in the emotional component of the response to the phasic pain, whereas a decrease in the pain rating indicates analgesia in response to the tonic pain. The results of our study suggest that chronic (45 d), intermittent (2 h/d) amplitude modulated RF field exposure to the peripubertal rat increases the emotional component of phasic pain over a basal eaualgesic state, while late response to tonic pain is decreased. The data suggest that amplitude modulated RF field differentially affects the mechanisms involved in the processing of various noxious stimuli.
有几份报告称，成年人暴露于电磁场（EMF）（单次或重复剂量，持续2 - 3周，时长从几分钟到几小时）后痛觉发生改变。常用的有害刺激是辐射热。已知伤害性反应会受到刺激、机体和环境特征的影响。我们研究了暴露于射频场（73.5 MHz调幅，16 Hz，功率密度1.33 mw/cm²，比吸收率 = 0.4 w/kg）45天（每天2小时）的生长期大鼠对各种有害刺激的伤害性反应模式。记录每只大鼠刺激伤害性传入神经以介导尾巴运动反应的阈电流（TF）、刺激期间的发声（VD）和放电后的发声（VA）；尾巴（TFL）和后爪（HPL）对热有害刺激的退缩潜伏期以及紧张性疼痛反应。TFL未受影响，HPL降低（p < 0.01），TF和VD的阈值未受影响，而VA的阈值显著降低。紧张性疼痛评分降低（p < 0.01）。VA阈值降低（p < 0.01）表明对阶段性疼痛反应的情绪成分增加，而疼痛评分降低表明对紧张性疼痛有镇痛作用。我们的研究结果表明，对青春期前大鼠进行慢性（45天）、间歇性（每天2小时）调幅射频场暴露会使阶段性疼痛的情绪成分在基础镇痛状态上增加，而对紧张性疼痛的晚期反应则降低。数据表明，调幅射频场对参与处理各种有害刺激的机制有不同影响。
