Radial arm maze performance of rats following repeated low level microwave radiation exposure

We examined the possibility of changes in "working" memory of rats following whole body exposure to microwave (MW) radiation. During each of 10 days, we exposed rats within circularly polarized waveguides for 45 min to 2450 MHz fields at whole body SARs of 0.6 W/kg (2 micros pulses, 500 pps), followed by testing in a 12 arm, radial arm maze (RAM). Rats received a preexposure injection of one of three psychoactive compounds or saline, to determine whether a compound would interact with MW exposure to affect performance in the maze. Error rate, i.e., reentry into arms already visited, and time to criterion data for 10 consecutive days of testing were analyzed by a three way analysis of variance (ANOVA) using main effects of "exposure" and "drug" and a repeated factor of "test day." Our alpha limit for significance was P <.05. Analyzes of error rates revealed no significant exposure effect, no significant drug effect and no significant interaction between the two main factors. There was a significant difference in test days, as expected, with repeated test-trial days, which indicates that learning was accomplished. There was no significant interaction of test day and the other two factors. The results of our analyzes of time to criterion data included no significant exposure effect, a significant drug effect, a significant test day effect, and a significant interaction between drug and test day factors. Post hoc analyzes of the drug factor revealed that rats treated with either physostigmine or nalrexone hydrochloride, took significantly longer to complete the maze task than rats pretreated with saline or with naloxone methodide. We conclude that there is no evidence from the current study that exposure to of MW radiation under parameters examined caused decrements in the ability of rats to learn the spatial memory task.

[1]  D. Olton,et al.  Animal Behavior Processes , 2022 .

[2]  Diane Dubreuil,et al.  Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks? , 2002, Behavioural Brain Research.

[3]  H. Schaller,et al.  Transient expression of SorCS in developing telencephalic and mesencephalic structures of the mouse , 2001, Neuroreport.

[4]  R. Glassman.  A “Theory of relativity” for cognitive elasticity of time and modality dimensions supporting constant working memory capacity: Involvement of harmonics among ultradian clocks? , 2000, Progress in Neuro-Psychopharmacology and Biological Psychiatry.

[5]  N. Edelstyn,et al.  The acute effects of exposure to the electromagnetic field emitted by mobile phones on human attention , 2002, Neuroreport.

[6]  M. Woodruff,et al.  Transplant-induced working memory deficits in hippocampectomized rats , 1993, Physiology & Behavior.

[7]  R. Glassman,et al.  Spatial working memory score of humans in a large radial maze, similar to published score of rats, implies capacity close to the magical number 7 ± 2 , 1994, Brain Research Bulletin.

[8]  J. D’andrea,et al.  Behavioral evaluation of microwave irradiation. , 1999, Bioelectromagnetics.

[9]  C. Kelche,et al.  Scopolamine treatment and fimbria-fornix lesions: Mimetic effects on radial maze performance , 1989, Physiology & Behavior.

[10]  A. Guy,et al.  Microwave irradiation affects radial-arm maze performance in the rat. , 1994, Bioelectromagnetics.

[11]  R. Wiley,et al.  Threshold relationship between lesion extent of the cholinergic basal forebrain in the rat and working memory impairment in the radial maze , 1999, Brain Research.

[12]  H. Lai,et al.  Research on the neurological effects of nonionizing radiation at the University of Washington. , 1992, Bioelectromagnetics.

[13]  K. Grasing,et al.  Acquisition of a Morris water maze task is impaired during early but not late withdrawal from morphine , 1996, Pharmacology Biochemistry and Behavior.

[14]  Eleanor R. Adair,et al.  Microwaves and thermoregulation , 1983 .

[15]  A. Guy,et al.  Acute low-level microwave exposure and central cholinergic activity: studies on irradiation parameters. , 1988, Bioelectromagnetics.

[16]  P Lavenex,et al.  Integration of olfactory information in a spatial representation enabling accurate arm choice in the radial arm maze. , 1996, Learning & memory.

[17]  A. Guy,et al.  Specific absorption rate in rats exposed to 2,450-MHz microwaves under seven exposure conditions. , 1985, Bioelectromagnetics.

[18]  Richard S. J. Frackowiak,et al.  Knowing where and getting there: a human navigation network. , 1998, Science.

[19]  M. Shannon.  Toxicology reviews: physostigmine. , 1998, Pediatric emergency care.

[20]  J. Juraska,et al.  Differential rearing experience, gender, and radial maze performance. , 1984, Developmental psychobiology.

[21]  C M Krause,et al.  Effects of electromagnetic fields emitted by cellular phones on the electroencephalogram during a visual working memory task , 2000, International journal of radiation biology.

[22]  Arthur W. Guy,et al.  Circularly polarized 2450-MHz waveguide system for chronic exposure of small animals to microwaves , 1979 .

[23]  B. J. Winer.  Statistical Principles in Experimental Design , 1992 .

[24]  David S. Olton,et al.  The radial arm maze as a tool in behavioral pharmacology , 1987, Physiology & Behavior.

[25]  A W Preece,et al.  Effect of a 915-MHz simulated mobile phone signal on cognitive function in man. , 1999, International journal of radiation biology.

[26]  A. Guy,et al.  Low-level microwave irradiation and central cholinergic systems , 1989, Pharmacology Biochemistry and Behavior.

[27]  H. Tilson,et al.  Intradentate colchicine disrupts the acquisition and performance of a working memory task in the radial arm maze. , 1988, Neurotoxicology.

[28]  R P Blackwell,et al.  Low-level exposure to pulsed 900 MHz microwave radiation does not cause deficits in the performance of a spatial learning task in mice. , 2000, Bioelectromagnetics.

[29]  Matti Laine,et al.  The effects of electromagnetic field emitted by GSM phones on working memory , 2000, Neuroreport.

[30]  A. Guy,et al.  Low‐Level Microwave Irradiations Affect Central Cholinergic Activity in the Rat , 1987, Journal of neurochemistry.

[31]  U. Schaeppi,et al.  Validation of a photobeam system for assessment of motor activity in rats. , 1988, Toxicology.

[32]  R. Beninger,et al.  Physostigmine, but not 3,4-diaminopyridine, improves radial maze performance in memory-impaired rats , 1995, Pharmacology Biochemistry and Behavior.

[33]  R. Glassman,et al.  Human performance with a seventeen-arm radial maze analog , 1993, Brain Research Bulletin.

[34]  D. Olton.  Mazes, maps, and memory. , 1979, The American psychologist.

[35]  G. Koelle.  Cholinesterases and Anticholinesterase Agents , 1963 .

[36]  E. Bostock,et al.  Effects of opiate antagonists on spatial memory in young and aged rats. , 1985, Behavioral and neural biology.

[37]  E. Levin,et al.  Nicotinic antagonist administration into the ventral hippocampus and spatial working memory in rats , 1997, Neuroscience.

[38]  S. Ramo,et al.  Fields and Waves in Communication Electronics , 1966 .

[39]  T. J. Walsh,et al.  The use of the radial arm maze in neurotoxicology , 1987, Physiology & Behavior.

[40]  J. H. Merritt,et al.  Chronic exposure of cancer-prone mice to low-level 2450 MHz radiofrequency radiation. , 1998, Bioelectromagnetics.

[41]  Robert B. Glassman,et al.  Human working memory capacity is 7 ± 2 in a radial maze with distracting interruption: possible implication for neural mechanisms of declarative and implicit long-term memory , 1998, Brain Research Bulletin.