Study type: Medical/biological study (experimental study)

Influence of microwave exposure on chlordiazepoxide effects in the mouse staircase test med./bio.

Published in: Pharmacol Biochem Behav 1994; 47 (4): 845-849

Aim of study (acc. to author)

To ascertain whether behavioral effects of benzodiazepines are altered by exposure to microwaves, the authors compared the performance of mice in the staircase test 30 min after pretreatment with chlordiazepoxide (8, 16, and 32 mg/kg) and immediately following a 5 min exposure to microwaves.

Background/further details

The mouse staircase test is an efficient test for preliminary assessment of anxiolytic and sedative effects of benzodiazepines.
Mice were irradiated in pairs at different specific absorption rates at a frequency of either 1.8 or 4.7 GHz (25 min after drug administration).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.8 GHz
Modulation type: CW
Exposure duration: continuous for 5 min
  • SAR: 4 W/kg average over mass (whole body)
  • SAR: 12 W/kg average over mass (whole body)
  • SAR: 36 W/kg average over mass (whole body)
Exposure 2: 4.7 GHz
Modulation type: CW
Exposure duration: continuous for 5 min
  • SAR: 4 W/kg average over mass (whole body)
  • SAR: 12 W/kg average over mass (whole body)
  • SAR: 36 W/kg average over mass (whole body)

Exposure 1

Main characteristics
Frequency 1.8 GHz
Type
Charakteristic
Exposure duration continuous for 5 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 2 m
Setup Mice were individually held inside Plexiglas cylindrical restrainers which were placed on a table in front of the standard gain pyramidal horn antenna and exposed in E-polarisation.
Sham exposure A sham exposure was conducted.
Additional info Sham irradiated mice were similarly restrained and placed inside the chamber out of the EMF.
Parameters
Measurand Value Type Method Mass Remarks
SAR 4 W/kg average over mass measured whole body -
SAR 12 W/kg average over mass measured whole body -
SAR 36 W/kg average over mass measured whole body -

Exposure 2

Main characteristics
Frequency 4.7 GHz
Type
Charakteristic
Exposure duration continuous for 5 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.46 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 4 W/kg average over mass measured whole body -
SAR 12 W/kg average over mass measured whole body -
SAR 36 W/kg average over mass measured whole body -

Reference articles

  • Allen SJ et al. (1979): Calorimetric Measurements of Microwave-Energy Absorption by Mice After Simultaneous Exposure of 18 Animals

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In sham-exposed animals, 8 mg/kg chlordiazepoxide increased the number of steps ascended (NSA) without affecting number of rears (NR). In sham-exposed animals, 16 mg/kg chlordiazepoxide increased the number of steps ascended (NSA) and decreased the number of rears (NR). And 32 mg/kg chlordiazepoxide then decreased both the number of steps ascended (NSA) and the number of rears (NR).
Microwave irradiation generally did not alter the number of steps ascended (NSA) or the number of rears in animals pretreated with lower doses of chlordiazepoxide. However, in animals pretreated with 32 mg/kg chlordiazepoxide, exposure to 4.7 GHz at 36 W/kg microwave exposure significantly reversed the reductions in NSA and NR (cf. sham exposure),- i.e. significantly greater numbers of steps ascended (NSA) and numbers of rears (NR) were revealed. This was not the case at 1.8 GHz.
These results indicate that exposure to microwaves can selectively alter effects of chlordiazepoxide in this psychopharmacological paradigm.

Study character:

Study funded by