ID Number		579
Study Type		In Vivo
Model		945 MHz (AM-4 Hz) exposure to rats and analysis of EEG profiles
Details		Wistar rats (n=8) were surgically implanted with carbon EEG electrodes and exposed (5 days post surgery) to 945 MHz (AM-4 Hz) at 0.1-0.2 mW/cm2 for 1 min on/1 min off for 10 min with a circular antenna placed 28-30 cm above the rat. Elevation of EEG asymmetry in the 10-14 Hz range was observed in exposed animals. In Vorobyov et al. (2005) freely moving rats implanted with carbon electrodes were exposed at 915 MHz (20-ms pulses with 4 Hz amplitude modulation) at 0.3 mW/cm2 for 30 min/d for 3 days. Exposure enhanced the fast EEG rhythms (18-30 Hz). In exposed rats, a psychoactive drug (scopolamine) did not cause a slowing in the EEG observed in unexposed rats. A similarity between the scopolamine-induced EEG in the exposed rats and that of physostigmine (enhances acetylcholine level in the brain) in unexposed rats was noted. The authors concluded that the results provide evidence that RF exposures amplitude modulated in the low frequency range can modify the cholinergic system in the rat brain. AUTHORS' ABSTRACT: Vorobyov et al. 2010 (IEEE #6109): PURPOSE: To compare the effects of repeated exposure to extremely low frequency-modulated microwaves (ELF-MW) on cortical and hypothalamic electroencephalograms (EEG). MATERIALS AND METHODS: In 10 freely moving rats with carbon electrodes implanted into the cortex and dorsomedial hypothalamus, averaged frequency spectra (0.5-30 Hz) of the EEG were studied for five consecutive days either under sham exposures (five rats) or under mixed sham/MW-exposures (five rats). The rats were exposed to ELF-MW (915 MHz, 20-ms pulse duration, approximately 0.3 mW/cm(2), 4 Hz) intermittently (1-min 'On', 1-min 'Off') for 10 min (specific absorption rate, SAR, approximately 0.7 mW/g on average) several times per day, with 10-min pre- and post-exposure periods. RESULTS: In baseline EEG, the activities of 3.2-6.0 Hz and 17.8-30.5 Hz dominated in the cortex and of 6.0-17.8 Hz in the hypothalamus. This cortical-hypothalamic imbalance was relatively stable at sham-exposures and insensitive to ELF-MW in all frequency ranges but one. ELF-MW increased the beta(2) (17.8-30.5 Hz) level in the hypothalamus to a greater extent than in the cortex, causing significant diminishing of the initial EEG bias between them. Moreover, a cumulative phenomenon under repeated exposures to ELF-MW was revealed. CONCLUSIONS: These results are in line with evidence that repeated low-level exposure to ELF-MW affects brain functioning and provide an additional approach when analysing underlying mechanisms.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Russian Accademy of Science, Russia
Funding Agency		Private/Instit.
Country		RUSSIAN FEDERATION
References		Vorobyov, V et al. Int. J. Rad. Biol., (2005) 80:691-698 Vorobyov, VV et al. Bioelectromagnetics, (1997) 18:293-298 Vorobyov, V et al. Int J Radiat Biol., (2010) 86:376-383
Comments		No SAR data.