Study type: Medical/biological study (experimental study)

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

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.



Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: pulsed
Exposure duration: continuous for 45 min

General information

Radial wooden 12- arm maze for behaviour test

Exposure 1

Main characteristics
Frequency 2.45 GHz
  • guided field
  • circular
Exposure duration continuous for 45 min
Modulation type pulsed
Pulse width 2 µs
Packets per second 500
Exposure setup
Exposure source
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).
Measurand Value Type Method Mass Remarks
power density 10 W/m² mean unspecified - -
SAR 600 µW/g mean unspecified whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
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:

Study funded by

Replication studies

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