| This project was designed to examine the effects of long-term electromagnetic fields on the production of melatonin and the subsequent sleep structure of rats. Electromagnetic fields (EMF) occur around any wire conducting electricity, from everyday appliances as hair dryers and toasters to large overhead transmission lines. All people encounter EMF every day of their lives. There are different types of EMF. One of the most famous examples is visible light. The form of EMF that I am discussing is considered extremely low frequency EMF, such as that described above emitting from common appliances and electrical wires. Electricity used in the US cycles 60 times a second (60 Hz). This frequency has been-deemed safe by chemists and physicists due to the very small amounts of radiation produced. However, biologists and experimental psychologists have uncovered a variety of possible health related ramifications due to long-term exposure. Scientific investigations have found that 60 Hz EMF may have direct or indirect effects on the pineal gland production of melatonin (Reiter, 1995). For example, melatonin production decreased in rats (Wilson, 1983) and humans (Graham, 1993) after exposure to EMF. Melatonin is a hormone produced in the pineal gland that has well-established effects on circadian timing of sleep in most animals (Arendt, Middleton, Stone, & Skene, 1999). To investigate these findings further, we exposed 18 male Sprague-Dawley rats to a 1000 milligauss magnetic field for one month. Urine was collected for the final 3 days of the exposure period for analysis of 6-sulphatoxymelatonin, the major catabolic product of melatonin found in urine. When exposure was completed and urine collected, sleep was analyzed for 24 hours. Results indicated that melatonin production was actually increased in the exposed animals. Results similar to our findings have been found (Nagy, 1997) and may indicate a compensatory mechanism is causing a rebound phenomenon. Sleep analysis demonstrated no significant changes in the sleep structure of exposed animals as compared to sham-exposed. Finally, new research paradigms are discussed to address findings. |
