ID Number		490
Study Type		In Vivo
Model		2450 MHz (CW, PW) exposure to rats and analysis of brain function and behavior.
Details		Sprague Dawley rats were exposed to 2450 MHz (PW - 2 microsec pulses at 500pps) to 0.6 or 1.2 W/kg whole body for 1 hour in a circular waveguide system (Guy et al (1979) Radio Sci 14(6S):63-74) (up to 2.0 W/kg in the brain). Exposures appeared to induce a learning deficit in both radial arm maze (Bioelectromagnetics, 1994, 15:95-104) and water maze (Bioelectromagnetics, (2000) 21:52-56) conditioned memory. Earlier studies by Lai et al suggested this might be a result of decrease in cholinergic nerve impulses in regions of learning, memory, consumatory and motivational behaviors (frontal cortex and hippocampus) due to increased opioid production. Other studies demonstrated MW exposure could reduce duration of barbiturate anesthesia, desynchronize barbituate-induced EEG patterns, increase barbiturate deposition in the brain, and affect the thermoregulatory and other actions of various drugs. The authors conclude that these MW effects may be mediated by an opioid pathway. The authors concede, however, that potential stress effects due to MW hearing from the PW exposures are possible. In more recent studies, rats underwent similar exposure (2450 MHz CW, whole body avg SAR = 1.2 W/kg) +/- a temporally incoherent 60 mG magnetic field superimposed on the RF signal. Exposure lasted 1 hour and was immediately followed by training or testing in a circular water maze (submerged platform for escape). The authors report that RF-only (non-pulsed, CW signal this time) exposed rats had a significant deficit in spatial learning. Exposure to 60 mG magnetic field alone had no effect, although simultaneous RF + magnetic field synergized to further attenuate the RF-induced learning deficit.
Findings		Effects
Status		Completed With Publication
Principal Investigator		University of Washington, USA - hlai@u.washington.edu
Funding Agency		NIH, USA
Country		UNITED STATES
References		Lai, H Physiology & Behavior, (2004) 82:785-789 Wang, B et al. Bioelectromagnetics, (2000) 21:52-56 Lai, H et al. Pharmacol. Biochem. Behav., (1996) 53:613-616 Lai, H et al. Bioelectromagnetics, (1994) 15:95-104 Lai, H et al. Bioelectromagnetics, (1992) 13:57-66 Lai, H et al. Bioelectromagnetics, (1992) 13:237-246 Lai, H et al. Bioelectromagnetics, (1991) 12:27-33 Lai, H et al. Brain Res. Bull., (1990) 25:609-612 Lai, H et al. Pharmac. Biochem. Behav., (1989) 33:131-138 Lai, H et al. Bioelectromagnetics, (1989) 10:203-208 Lai, H et al. J. Neurochem., (1987) 48:40-45 Lai, H et al. Bioelectromagnetics, (1988) 9:355-362 Lai, H et al. Pharmac. Biochem. Behav., (1987) 27:635-639 Lai, H et al. IEEE Eng. Med. Biol., (1987) 6:31-36 Lai, H et al. Pharmac. Biochem. Behav., (1986) 24:151-153 Lai, H et al. Psychopharmacology, (1986) 88:354-361 Lai, H et al. Bioelectromagnetics, (1985) 6:207- Lai, H et al. Bioelectromagnetics, (1983) 4:205-214 Lai, H et al. Bioelectromagnetics, (1984) 5:203-211 Lai, H et al. IEEE Trans. Microwave Theory Tech., (1984) 32:882-886 Lai, H et al. Bioelectromagnetics, (1984) 5:213-220 Lai, H et al. J. Neurochem., (1984) 48:40-45 Lai, H et al. Bioelectromagnetics, (1983) 4:205-214 Lai, H Mobile Communications and Public Health. CRC Press, ISBN 9781138568426., (2019) Chapter 8:187-222
Comments		The early observations were consistent with a stress response due to the MW hearing effect of the high peak pulse 2450 MHz (PW) RF used for exposure, although more recent studies (2004) suggest the effect could also be produced using 2450 MHz CW exposures. There is no information about the way the rats were handled before and during the experiments, making it possible that some stress situations during handling may not have been controlled for. Lai reported that RF exposure altered spatial working memory of rats in a radial maze, and correlated this with an increase in benzodiazepine receptors in the cerebral cortex. However Cosquer et al. (2004) state in their replication attempt paper that the literature shows stressful situations are associated with a decreased number of benzodiazepine receptors, not an increase. Not supported by recent studies of Crouzier (2006), but not an exact replication