Effect of Chronic Intermittent Exposure to AM Radiofrequency Field on Responses to Various Types of Noxious Stimuli in Growing Rats

Abstract

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.

“Dirty electricity”: what, where, and should we care?

“…Because of its dependency on local factors, the exposure estimates will need to be obtained on an individual level rather than relying on aggregated measures such as distance to transmission lines and transformers (Breckenkamp et al, 2008;Duyan et al, 2008;Maslanyj et al, 2009). Further complications in exposure estimation will be introduced as , even though some data suggest biological systems might be especially susceptible to non-linear 'resonant' frequency-amplitude combinations (Zhadin, 2001;Binhi and Savin, 2002), biological effects from HFVT might be caused by the intermittent nature of HFVT compared to the LF-RF frequency harmonic sine waves that carry the transients (Ivancsits et al, 2002;Mathur, 2008). These factors will most likely only further increase the potential for exposure misclassification in studies relating ''standard'' EMF exposure metrics to health effects (Kheifets et al, 2009;Schuz et al, 2009).…”

Effect of Radiofrequency Electromagnetic Fields on Thermal Sensitivity in the Rat

“…In previous data in healthy volunteers, cutaneous thermal pain perception was influenced by an overtime effect of head RF-EMF exposure (UMTS 1947 MHz, 1.75 W/kg) using visual analogue subjective pain rating scale [ 13 ]. In rodents, Mathur et al [ 14 ] showed that intermittent RF-EMF exposures (0.4 W/kg, 73.5 MHz, whole body) heightened the emotional component of phasic pain. Bodera et al [ 15 ] showed that RF-EMF exposures (1500 MHz and 1800 MHz) transiently suppressed the effect of tramadol, an analgesic acting through opioids and monoaminergic transmissions.…”

The Effect of a Single 30-Min Long Term Evolution Mobile Phone-Like Exposure on Thermal Pain Threshold of Young Healthy Volunteers

“…In contrast, acute exposure (30 min) of specific ELF MFs demonstrated consistent inhibitory effect on opioid-induced analgesia [ 7 , 8 , 9 , 10 ]. In peripubertal rats, the chronic (45 days) and intermittent (2 h/day) exposure to amplitude modulated RF EMF facilitated the emotional component of phasic pain, while late responses to tonic pain stimuli were decreased [ 11 ].…”