Medical/biological study (experimental study)

Microwave irradiation affects radial-arm maze performance in the rat med./bio.

By: Lai H, Horita A, Guy AW

Published in: Bioelectromagnetics 1994; 15 (2): 95-104

Aim of study (acc. to author)

To investigate whether cholinergic systems and endogenous opioids play a role in the microwave-induced spatial memory deficit in the radial-arm maze.

Background/further details

A series of experiments was carried out to study whether pretreatment with the cholinergic agonist physostigmine or the opiate antagonist naltrexone could reverse this behavioral effect of microwave exposure. In addition, since the origin (peripheral or central) of the endogenous opioid effect was not known, the effect of pretreatment with the peripheral opiate antagonist naloxone methiodide was also studied. If the behavioral effect involves only endogenous opioids inside the CNS, treatment with naloxone methiodide would have no significant effect on the spatial memory deficit.

Endpoint

cognitive/behavioral endpoints: role of cholinergic systems and endogenous opioids in the microwave-induced spatial memory deficit

Exposure

- 2.45 GHz
- microwaves
- PW pulsed wave

Exposure	Parameters
Exposure 1: 2.45 GHz Modulation type: pulsed Exposure duration: continuous for 45 min	power density: 10 W/m² mean SAR: 600 µW/g mean (whole body)

General information

Radial wooden 12- arm maze for behaviour test

Exposure 1

Main characteristics

Frequency	2.45 GHz
Type	electromagnetic field
Waveform	sinusoidal
Charakteristic	guided field
Polarization	circular
Exposure duration	continuous for 45 min

Modulation

Modulation type	pulsed
Pulse width	2 µs
Packets per second	500

Exposure setup

Exposure source	cylindrical waveguide exposure system, (8 cylindrical tubes)
Chamber	circular waveguide with circularly polarized TE11 mode field; Each tube containing a plastic chamber to house a rat
Additional info	Source of exposure: described in Guy et al. [1979] Guy AW. Wallace J. McDougall JA (1979).

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	10 W/m²	mean	unspecified	-	-
SAR	600 µW/g	mean	unspecified	whole body	-

Additional parameter details

SAR values varied from 0.5 to 2.0 W/kg per mW/cm².

Exposed system:

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: working memory, spatial memory task (radial arm maze; error rate (reentry into arms already visited))

Investigated system:

investigation on living organism

Time of investigation:

after exposure

Main outcome of study (acc. to author)

After exposure the rats showed retarded learning while performing in the radial-arm maze to obtain food rewards (food was situated at the end of each arm), indicating a deficit in spatial working memory function. This behavioral deficit was reversed by pretreatment before radiation with the cholinergic agonist physostigmine or the opiate antagonist naltrexone. The pretreatment with the peripheral opiate antagonist naloxone methiodide showed no reversal of effect. The results indicate that both cholinergic and endogenous opioid neurotransmitter systems in the brain are involved in the microwave-induced spatial memory deficit.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA

Replication studies

Cobb BL et al. (2004): Radial arm maze performance of rats following repeated low level microwave radiation exposure
Cassel JC et al. (2004): Whole-body exposure to 2.45 GHz electromagnetic fields does not alter radial-maze performance in rats

Ntzouni MP et al. (2013): Transient and cumulative memory impairments induced by GSM 1.8 GHz cell phone signal in a mouse model
Lu Y et al. (2012): Glucose administration attenuates spatial memory deficits induced by chronic low-power-density microwave exposure
Ntzouni MP et al. (2011): Short-term memory in mice is affected by mobile phone radiation
Ammari M et al. (2008): Effect of head-only sub-chronic and chronic exposure to 900-MHz GSM electromagnetic fields on spatial memory in rats
Vozeh F et al. (2007): Study of high-frequency electromagnetic field effect on some somatic and neuro-behavioral characteristics in healthy and neurodefective mice
Cobb BL et al. (2004): Radial arm maze performance of rats following repeated low level microwave radiation exposure
Cassel JC et al. (2004): Whole-body exposure to 2.45 GHz electromagnetic fields does not alter radial-maze performance in rats