EMF-Portal | Microwave alteration of the blood-brain barrier system of rats

Microwave alteration of the blood-brain barrier system of rats med./bio.

Aim of study (acc. to author)

Endpoint

Exposure

Exposure	Parameters
Exposure 1: 1.3 GHz Modulation type: CW Exposure duration: continuous for 20 min	power density: 30 µW/cm² mean (0.05 mWcm², 0.1 mW/cm², 0.2 mW/cm², 0.3 mW/cm², 0.4 mW/cm², 0.6 mW/cm², 0.8 mW/cm² and 2.0 mW/cm²)
Exposure 2: 1.3 GHz Modulation type: pulsed Exposure duration: 20 min	power density: 1 W/m² mean (at 1000 pps and 0.5 µs pulse width) power density: 2 W/m² mean (at 1000 pps and 0.5 µs pulse width) power density: 3 W/m² mean (at 1000 pps and 0.5 µs pulse width) power density: 4 W/m² mean (at 1000 pps and 0.5 µs pulse width) power density: 6 W/m² mean (at 1000 pps and 0.5 µs pulse width) power density: 20 W/m² mean (at 1000 pps and 10 µs pulse width) power density: 30 µW/cm² mean (at 5 pps and 10 µs pulse width) power density: 50 nW/cm² mean (at 5 pps and 10 µs pulse width) power density: 3 W/m² mean (at 50 pps and 10 µs pulse width) power density: 3 W/m² mean (at 250 pps and 20 µs pulse width) power density: 3 W/m² mean (at 250 pps and 2 µs pulse width) power density: 8 W/m² mean (at 1000 pps and 0.5 µs pulse width)

Parameters

Exposure 1: 1.3 GHz

Modulation type: CW

Exposure duration: continuous for 20 min

power density: 30 µW/cm² mean (0.05 mWcm², 0.1 mW/cm², 0.2 mW/cm², 0.3 mW/cm², 0.4 mW/cm², 0.6 mW/cm², 0.8 mW/cm² and 2.0 mW/cm²)

Exposure 2: 1.3 GHz

Modulation type: pulsed

Exposure duration: 20 min

power density: 1 W/m² mean (at 1000 pps and 0.5 µs pulse width)
power density: 2 W/m² mean (at 1000 pps and 0.5 µs pulse width)
power density: 3 W/m² mean (at 1000 pps and 0.5 µs pulse width)
power density: 4 W/m² mean (at 1000 pps and 0.5 µs pulse width)
power density: 6 W/m² mean (at 1000 pps and 0.5 µs pulse width)
power density: 20 W/m² mean (at 1000 pps and 10 µs pulse width)
power density: 30 µW/cm² mean (at 5 pps and 10 µs pulse width)
power density: 50 nW/cm² mean (at 5 pps and 10 µs pulse width)
power density: 3 W/m² mean (at 50 pps and 10 µs pulse width)
power density: 3 W/m² mean (at 250 pps and 20 µs pulse width)
power density: 3 W/m² mean (at 250 pps and 2 µs pulse width)
power density: 8 W/m² mean (at 1000 pps and 0.5 µs pulse width)

Exposure 1

Main characteristics

Frequency	1.3 GHz
Type	electromagnetic field
Waveform	sinusoidal
Polarization	linear
Exposure duration	continuous for 20 min

Modulation

Modulation type	CW

Exposure setup

Exposure source	horn antenna
Chamber	anechoic chamber (5 m x 5 m x10m) maintained at 22°C, wedge and pyramidally shaped absorber (- 40dB), styrofoam pedestal
Additional info	Rats were exposed in one of two different exposure procedures; the rats were irradiated without being anesthetized and were placed in a pie shaped, well ventilated styrofoam enclosure. The box was placed on a styrofoam platform with the rat facing the center of the emitting horn and aligned with the longitudinal axis of the horn. The rats could not turn around. In other tests rats were anesthetized and placed directly on the styrofoam platform facing the mouth of the horn.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	30 µW/cm²	mean	measured	-	0.05 mWcm², 0.1 mW/cm², 0.2 mW/cm², 0.3 mW/cm², 0.4 mW/cm², 0.6 mW/cm², 0.8 mW/cm² and 2.0 mW/cm²

Exposure 2

Main characteristics

Frequency	1.3 GHz
Type	electromagnetic field
Waveform	sinusoidal
Exposure duration	20 min

Modulation

Modulation type	pulsed
Additional info	signals with 5, 50, 250, and 1000 pps and 0.5 µs, 2.0 µs, 10 µs and 20 µs were used.

Exposure setup

Exposure source	same setup as exposure 1

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	1 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width
power density	2 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width
power density	3 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width
power density	4 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width
power density	6 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width
power density	20 W/m²	mean	measured	-	at 1000 pps and 10 µs pulse width
power density	30 µW/cm²	mean	measured	-	at 5 pps and 10 µs pulse width
power density	50 nW/cm²	mean	measured	-	at 5 pps and 10 µs pulse width
power density	3 W/m²	mean	measured	-	at 50 pps and 10 µs pulse width
power density	3 W/m²	mean	measured	-	at 250 pps and 20 µs pulse width
power density	3 W/m²	mean	measured	-	at 250 pps and 2 µs pulse width
power density	8 W/m²	mean	measured	-	at 1000 pps and 0.5 µs pulse width

Exposed system:

animal
rat/Wistar
whole body

Methods Endpoint/measurement parameters/methodology

Investigated system:

brain sections: hypothalamus, cerebellum, hippocampus, cortex, medulla

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data confirmed the results of the study of Frey et al. (1975): microwaves cause a temporary increase in permeability of blood-brain barrier. This effect was dependent on the field characteristics.

Study funded by

not stated/no funding

Replicated studies

Frey AH et al. (1975): Neural function and behavior: defining the relationship

Replication studies

Ward TR et al. (1985): Blood-brain barrier permeation in the rat during exposure to low-power 1.7-GHz microwave radiation

Merritt JH et al. (1978): Studies on blood-brain barrier permeability after microwave-radiation

Sirav B et al. (2011): Effects of radiofrequency radiation exposure on blood-brain barrier permeability in male and female rats

Eberhardt JL et al. (2008): Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones

Microwave alteration of the blood-brain barrier system of rats med./bio.

Aim of study (acc. to author)

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

Replicated studies

Replication studies

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