Study type: Medical/biological study (experimental study)

Hyperactivity caused by a nitric oxide synthase inhibitor is countered by ultra-wideband pulses med./bio.

By: Seaman RL, Belt ML, Doyle JM, Mathur SP
Published in: Bioelectromagnetics 1999; 20 (7): 431-439
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Aim of study (acc. to author)

To investigate the potential action of ultra wideband (UWB) electromagnetic field pulses on effects of NG-nitro-L-arginine-methyl-ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), on nociception and locomotor activity in mice. Mice were injected with saline or 50 mg/kg L-NAME and exposed for 30 min to no pulses (sham exposure) or UWB pulses.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 600 Hz–1.11 GHz
Modulation type: pulsed
Exposure duration: continuous for 30 min

Exposure 1

Main characteristics
Frequency 600 Hz–1.11 GHz
Type
Waveform
Charakteristic
  • guided field
Exposure duration continuous for 30 min
Modulation
Modulation type pulsed
Pulse width 0.9 ns
Rise time 160 ps
Repetition frequency 600 Hz
Exposure setup
Exposure source
Chamber The GTEM cell, a tapered two-conductor transmission line, was positioned so that one ground plane wall was horizontal.
Setup Animals were exposed in a well-ventilated clear plastic holder consisting of an upright cylinder with 12.1-cm ID, 0.32-cm walls, a floor of four concentric loops of 0.63-cm plastic rod, and a plastic cover. The top portion of the holder containing the animal was 4.6 cm high and 3.8 cm above the ground plane.
Sham exposure A sham exposure was conducted.
Additional info Two four-inch speakers outside the cell provided broadband noise for auditory masking of the UWB generator.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 102 kV/m peak value measured - ± 1 kV/m
SAR 37 mW/kg mean estimated whole body -
Additional parameter details

Background low-frequency fields in the laboratory were less than 0.1 µT.

Measurement and calculation details

A D-dot probe was mounted in the wall of the GTEM cell to detect the UWB pulses. Estimates of whole-body SAR based on the power spectrum, the normalised SAR for a prolate spheroidal model of a medium-sized mouse [Durney et al., 1986], and the duty cycle were averaged for k- and H-polarisations of the animal.

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

L-NAME by itself increased mean first-response and back-paw-lick response latencies and mean locomotor activity. Irradiation by UWB pulses reduced the L-NAME-induced increase in back-paw-lick latency by 22 %, but this change was not statistically significant. The L-NAME-induced hyperactivity was not observed after UWB exposure. Reduction and cancellation of effects of L-NAME suggest activation of opposing mechanism(s) by the UWB pulses. This possibly includes increase of nitric oxide production by NOS. The action(s) of UWB pulses appears to be more effective on locomotor activity than on thermal nociception in mice.

Study character:

Study funded by

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