Tehran University Medical Journal

Background: Extremely low frequency (0-300 Hz) fields from power lines, electronic equipment and medical devices, have been reported to produce various biological effects. Global system for mobile (GSM) is most largely used in everybody's life. This system utilizes a low frequency band as well as a high frequency range of electromagnetic field. This study investigated the effects of 217 Hz electromagnetic field (the modulating signal in GSM) on spatial learning and memory in rat.
Methods: Twenty four male Wistar rat (200- 250 g) were randomly divided in to three groups as: test, sham and control. Using a Helmholtz coil system, the test group was exposed to a uniform pulsed EMF of 200 µT (micro Tesla) intensity for 4 h/day for 21 days (2 time in a day). This procedure was repeated for the sham group but with no field. All groups were trained prior to the day 21 on the 15th day for five days four trial per day in Morris Water-Maze system. Then the probe test was carried out for 60 seconds with no platform.
Results: The ANOVA test revealed that no significant differences were found between control and exposed rats in all day of learning acquisition. Also, in probe test for investigating the memory, no significant differences observed. (P≤0.05 is accepted for significant level.
Conclusion: This finding is in consistent with previous studies and indicates low frequency band of electromagnetic fields (EMF) (200 µT intensity) in cell phone may not have any effect on the learning acquisition and spatial memory in rat.

Background: Widespread of telecommunication systems in recent years, have raised the concerns on the possible danger of cell phone radiations on human body. Thus, the study of the electromagnetic fields on proteins, particularly the membrane nano channel forming proteins is of great importance. These proteins are responsible for keeping certain physic-chemical condition within cells and managing cell communication. Here, the effects of cell phones radiation on the activity of a single nanopore ion channel forming protein, OmpF, have been studied biophysically.
Methods: Planar lipid bilayers were made based on Montal and Muller technique, and the activity of single OmpF channel reconstituted by electrical shock was recorded and analyzed by means of voltage-clamp technique at 20 ˚C. The planar lipid bilayers were formed from the monolayers made on a 60 μm diameter aperture in the 20 μm thick Teflon film that separated two (cis and trans) compartments of the glass chamber. In this practical approach we were able to analyze characteristics of an individual channel at different chemical and physical experimental conditions. The voltage clamp was used to measure the channel’s conductance, voltage sensitivity, gating patterns in time scales as low as microseconds in real time. 
Results: Our results showed that exposure of single voltage dependent channel, OmpF, to EMF of cell phone at high-frequency has a significant influence on the voltage sensitivity, gating properties and substate numbers of the single channel but has no effect on single-channel conductance. Regarding to the relaxation time, the channel also recovers in the millisecond time range when the field is removed.
Conclusion: We observed an increase in the voltage sensitivity of the OmpF single channel while it had no effect on the single-channel conductance, which is remained to be further elucidated.