Medical/biological study (experimental study)

Effect of Extremely Low Frequency Electromagnetic Field and/or GABAB Receptors on Foot Shock-induced Aggression in Rats med./bio.

By: Fard MT, Bahaeddini A, Shomali T, Haghighi SK

Published in: Basic Clin Neurosci 2014; 5 (2): 169-172

Aggression constitutes a serious clinical and social problem. Neurotransmitters such as gamma aminobutyric acid (GABA) play a key role in modulation of aggression in all mammalian species. On the other hand, strong magnetic fields may influence the central nervous system. Therefore, the possible correlation of magnetic field exposure and aggression as well as the role of GABA_B receptors should be investigated.
10 groups of rats were examined (n= 5 per group): 1.) sham exposure + saline, 2.) exposure + saline, 3.) sham exposure + 100 mg of the GABA_B antagonist CGP35348 per kg body weight, 4.) exposure + 100 mg/kg of CGP35348, 5.) sham exposure + 200 mg/kg CGP35348, 6.) exposure + 200 mg/kg CGP35348, 7.) sham exposure + 1.7 mg of the GABA_B agonist baclofen per kg body weight, 8.) exposure + 1.7 mg/kg baclofen, 9.) sham exposure + 3 mg/kg baclofen and 10.) exposure + 3 mg/kg baclofen. After the exposure period, rats received the substances via intraperitoneal injection and were tested for aggression behavior for 20 minutes.

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 8 h/day for 30 days	magnetic flux density: 500 µT

Exposure source	coil(s)
Setup	the magnetic field chamber consisted of a 70 x 120 x 30 cm wooden cage; three coils of electrically insulated 1 mm copper wire with 200 turns each were wound around the outer surface at equal distance; coils were connected in parallel and sealed with adhesive bandage; electrical source was an autotransformer with the input of 50 Hz and 220 V; field was homogeneous in a zone of 21 cm distance from the transverse borders and 9 cm from the longitudinal borders
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	500 µT	-	measured	-	-

Exposed system:

cognitive/behavioral endpoints: aggression behavior as a response of an electrical foot shock (2 mA for 5 minutes in 3 seconds intervals): number of lateral threat, lifted up on the hind paws threat, biting, attacking, chasing, approaching

Investigated system:

Time of investigation:

No significant differences were observed between magnetic field exposed (group 2) and sham exposed rats (group 1). Only rats exposed to magnetic fields and treated with 100 mg/kg CGP35348 (group 4) showed a significantly increased number of "lifted up threats" compared to magnetic field exposed rats with saline injection (group 2) and compared to sham exposed rats with 100 mg CGP35348 (group 3).
The authors conclude that extremely low frequency magnetic fields alone or in combination with a GABA_B-agonist or -antagonist have no influence on the aggression behavior of rats in the used aggression model.

Study character:

Yang G et al. (2015): Exposure to 50 Hz magnetic field modulates GABA currents in cerebellar granule neurons through an EP receptor-mediated PKC pathway
Salunke BP et al. (2014): Involvement of NMDA receptor in low-frequency magnetic field-induced anxiety in mice
Kitaoka K et al. (2013): Chronic exposure to an extremely low-frequency magnetic field induces depression-like behavior and corticosterone secretion without enhancement of the hypothalamic-pituitary-adrenal axis in mice
Balassa T et al. (2009): Effect of short-term 50 Hz electromagnetic field exposure on the behavior of rats
Xu C et al. (2008): GABA(B) receptor activation mediates frequency-dependent plasticity of developing GABAergic synapses
Jeong JH et al. (2005): Benzodiazepine system is involved in hyperalgesia in rats induced by the exposure to extremely low frequency magnetic fields