The influence of the magnetic field on the life of organisms has recently been a discussed topic in the media, and in the past our section has also addressed it. Tereza Kolbabová from the CULS Faculty of Forestry and Wood Sciences focused on it from a slightly different point of view in her doctoral thesis.
In this project, which is part of a broader program of magneto-biological research led by prof. Hynek Burda, the scientist was interested in how an extremely low-frequency oscillating magnetic field (such as under high voltage, for example) affects the secretion of melatonin (popularly known as the "sleep hormone"). This is a topical issue, as interference of the earth's magnetic field by high voltage lines, a phenomenon known to physicists, has been increasingly discussed in recent decades as a risk factor for cancer (especially breast cancer and childhood leukaemia), and farmers have suspected high voltage over pastures from reducing the performance and condition of their cows. The link is unknown, but it is explained by reduction in melatonin production, with melatonin being an important antioxidant (similar to vitamins C and E, for example), and thus possibly suppressing cancer growth. The second hypothesis is based on the fact that the disruption of the magnetic field in some way (with the participation of melatonin) disturbs the natural biorhythm, which in turn leads again to disruption of some basic life functions and to reduce the body's defences and increase morbidity. The third hypothesis then assumes that the oscillating magnetic field during sleep (rest, immobility) gives the brain a false message that the head is rotating, which is not confirmed by the equilibrium system, and as a result of this conflicting sensory information, so-called vegetative disorders occur, similar to when the balance system and sight provide dissenting information (feelings from sailing on a stormy sea, riding a carousel or perceiving rapid stroboscopic changes in lights and shadows are certainly familiar to readers).
Even on these important issues, the presented study should have shed more light. "The study was performed on approximately one-month-old calves divided into test and control groups. For the animals, the experiment was not stressful. The test group was placed in commonly used boxes, which were wrapped on the outside with a coil, which was used to simulate changes in the Earth's magnetic field under high-voltage wires. The saliva of these calves was sampled at regular intervals using special tampons, "says Tereza Kolbabová from FLD CULS in Prague. The concentration of melatonin in saliva was then determined in a specialized laboratory. The shortcomings of some previous experiments dealing with this issue were to be eliminated by the above-standard length of the experiment (35 days) and double repetition (summer and winter). During the described period, the calves were exposed to a magnetic field (50/60 Hz) while monitoring the levels of melatonin in their blood.
The results are crucial, as they were able to explain, among other things, the inconsistency of previous experiments, which neglected the effect of the season, the length of the photoperiod, respectively. It turned out that it depends very much at what time of year the study takes place. While in winter the oscillating magnetic field has a significant inhibitory effect on melatonin production similar to light, in summer unexpectedly and paradoxically the experimental animals had higher levels of this hormone in their blood than the control sample.
As is usually the case with biomedical experiments, the number of new questions is greater than the answers found. "The length of the photoperiod proved to be a key factor in melatonin production in our experiment, and since this indicator is closely related to the production of serotonin, a biologically active substance whose deficiency contributes to depression, sleep disorders, etc., we would like to focus our work in future to this very substance, which is released during the light day, “adds Tereza Kolbabová to the study.
Ing. Tereza Kolbabová
She is a doctoral student at the Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, CULS, where she deals with the sensory ecology of mammals.
Prepared by: Jiří Lehejček