Study type: Medical/biological study (experimental study)

The evaluation of biological efficiency of electromagnetic fields generated by implanted radiotelemetric transmitters used in space research on animals. med./bio.

Published in: Physiologist 1992; 35 (1) Suppl: S248-S249

Aim of study (acc. to author)

To examine biological effects of electromagnetic impulses generated by implanted biotelemetric systems (BTS) similar to those used in space experiments on rats.

Background/further details

The rats were divided in 5 groups: 1) vivarium control rats, 2) BTS mock-up implanted rats, 3) BTS implanted rats exposed to external electromagnetic fields, 4) BTS implanted rats, and 5) BTS mock-up implanted rats exposed to external electromagnetic fields.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 455 kHz
Exposure duration: continuous; 6-week experiment
Exposure 2: 455 kHz
Modulation type: single pulse
Exposure duration: interpulse interval of 300 s in a 6-week experiment

General information

Two types of abdominally implanted biotelemetric systems (BTS) of extended ellipsoid shape (8 mm x 18 mm) were used: An active battery powered one, generating continuous radio signals, and a passive one containing microcircuits excited by an external EMF impulse. Animals were divided into five groups: 20 vivarium control rats, 5 active biotelemetric systems (BTS) implanted rats, 5 passive BTS implanted rats exposed to external EMF, 10 BTS mock-up implanted rats and 10 BTS mock-up implanted rats exposed to external EMF.

Exposure 1

Main characteristics
Frequency 455 kHz
Type
Exposure duration continuous; 6-week experiment
Modulation
Modulation type unspecified
Additional info

active biotelemetric system

Exposure setup
Exposure source
  • active biotelemetric system
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.01 mT - - - 10-2-10-3 mT

Exposure 2

Main characteristics
Frequency 455 kHz
Type
Exposure duration interpulse interval of 300 s in a 6-week experiment
Modulation
Modulation type single pulse
Pulse width 200 ms
Exposure setup
Exposure source
  • passive biotelemetric system, transducer
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.01 mT - - - 10-2-10-3 mT

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The observed changes in the membranes and hormone levels are sufficient characteristics of biological efficiency of used electromagnetic fields. The rates of calcium ion transport in homogenates of femoral skeletal muscle and myocardium revealed no significant differences between experimental groups. Measurements of total charge of sarcoplasmic reticulum membranes from the same types of muscles exhibited an increase of negative charge in SR from exposed rats. A decrease of sodium potassium ATPase (Na+-K+-ATPase) specific activity in hepatocyte membranes of exposed animals have been observed. Inhibition of ATPase activity agrees with an increase in total negative charge of liver microsomes from the rats of the same group.The blood corticosterone level of mock-up animals was diminished by 70% as opposed to that of vivarium control animals. An additional irradiation to the external electromagnetic fields decreased the hormone level in the BTS rats, and, by contrast, increased it in those rats with implanted mock-ups. Thyroxine measurements showed the tendency for an increase of its level in the implanted BTS animals and a significant elevation in the implanted mock-up rats. Electromagnetic field exposure decreased the thyroxine level in both groups. Biorhythms of locomotor activity and body temperature of rats revealed some influence of the external electromagnetic field.

Study character:

Study funded by