Interaction of γ Aminobutyric Acid B Receptors and Electromagnetic Field in the Fear Response

One of the most neurotransmission system consistently linked with fear response is GABAergic system. GABA through GABA_B receptor can influence fear response. The aim of the present investigation was to examine the effect of IP injection of baclofen (GABA_B agonist) and CGP35348 (GABA_B antagonist) along with EMF exposure on frequency of fear response. Fifty adult male rats weighing 180-200 g were used. Animals were divided in ten groups, of which five groups were exposed to ELF-EMF for 30 days at 8 h day^-1 in a solenoid, creating an electromagnetic field of 500 µT by a 50 Hz electrical current. Animals were then treated with various doses of baclofen and CGP35348 before being exposed to electrical shock. Each animal were received 100 electrical shocks every session. After shock induction, the fear response was determined by monitoring the reaction of shocked animals to a normal rat which was placed in the electroshock chamber. Data was analyzed by Mann-Whitney test. Significant level was considered to be p<0.05. It was shown that injection of baclofen and CGP35348 did not induce any significant change in fear response in without EMF groups, while both of baclofen and CGP35348 significantly increased frequency of fear response in EMF exposure male rats. Results indicated that GABAB receptors and EMF exposure possibly involved in the modulation of fear response.