Study type: Medical/biological study (experimental study)

Acute effects of pulsed microwaves and 3-nitropropionic acid on neuronal ultrastructure in the rat caudate-putamen. med./bio.

Published in: Bioelectromagnetics 2005; 26 (2): 82-101

Aim of study (acc. to author)

To study possible combined effects of 3-nitropropionic acid induced chemical hypoxia and microwave exposure in the rat caudate-putamen.

Background/further details

3-nitropropionic acid irreversibly inhibits succinate dehydrogenase in the brain. This reduces production of adenosine triphosphate and the resulting interruption in energy metabolism can trigger oxidative stress, nitric oxide production and NMDA receptor activation consequently lead to neuronal cell death.
Rats were given doses of 10 mg/kg 3-nitropropionic acid and 1.5 h after were exposed to microwave irradiation.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.25 GHz
Modulation type: pulsed
Exposure duration: 30 min/day for 2 days
Exposure 2: 1.25 GHz
Modulation type: pulsed
Exposure duration: 30 min/day for 2 days

Exposure 1

Main characteristics
Frequency 1.25 GHz
Charakteristic
  • guided field
Exposure duration 30 min/day for 2 days
Modulation
Modulation type pulsed
Pulse width 5.9 µs
Repetition frequency 10 Hz
Exposure setup
Exposure source
Chamber Anechoic chamber maintained at 23°C
Setup Animals were placed in a plastic holder in front of the open end waveguide at a distance of 85 cm.
Additional info Animals were injected with saline or 10 mg/kg 3-nitropropionic acid 1.5 h before the exposure.
Parameters
Measurand Value Type Method Mass Remarks
SAR 600 µW/g mean calculated whole body -

Exposure 2

Main characteristics
Frequency 1.25 GHz
Charakteristic
  • guided field
Exposure duration 30 min/day for 2 days
Modulation
Modulation type pulsed
Pulse width 5.9 µs
Repetition frequency 10 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 6 mW/g mean calculated whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Tissue samples showed no injury with light microscope methods. Assessment of ultrastructure of randomly selected neurons from the same samples did reveal differences. Administration of 3-nitropropionic acid significantly increased endoplasmic reticulum intracisternal width, endoplasmic reticulum area density, and nuclear envelope thickness. Microwave irradiation at 6 W/kg alone also significantly increased these measures. Exposure of 3-nitropropionic acid treated rats at 6 W/kg significantly increased effects of 3-nitropropionic acid on ultrastructure. Although irradiation at 0.6 W/kg alone did not affect ultrastructure measures, exposure of 3-nitropropionic acid treated rats at 0.6 W/kg reduced the effects of 3-nitropropionic acid.
The authors concluded that 3-nitropropionic acid changed neuronal ultrastructure and that the microwave exposures used here altered neuronal ultrastructure in ways that depended on microwave SAR and neuron metabolic status. The apparent cancellation of 3-nitropropionic acid induced changes by exposure to pulsed microwaves at 0.6 W/kg indicated the possibility that such irradiation can protect against the effects of mitochondrial toxins on the nervous system.

Study character:

Study funded by