[Frontiers in Bioscience 13, 6106-6125, May 1, 2008]

Effects of static magnetic fields in biology: role of free radicals

Hideyuki Okano

International Innovation Center, Kyoto University, Kyoto, Japan


1. Abstract
2. Introduction
3. Weak-intensity SMF
3.1. Magnetic compass is based on "a radical pair mechanism"
3.2. Impact of geomagnetic activity on melatonin
3.3. Weak SMF effects on biochemical reactions
3.4. Summary of weak SMF effects on magnetic compass, melatonin release and biochemical reactions
4. Moderate-intensity SMF
4.1. Control of biochemical reactions with moderate SMF
4.2. Moderate SMF effects on ROS
4.3. Moderate SMF effects on RNS
4.4. Summary of moderate SMF effects on FRR
5. Strong-intensity SMF
5.1. Control of biochemical reactions with strong SMF
5.2. Strong SMF effects on ROS
5.3. Strong SMF effects on RNS
5.4. Summary of strong SMF effects on FRR
6. Perspectives
7. Conclusions
8. Acknowledgement
9. References


Biological systems can respond to a wide range of static magnetic fields (SMF). Some of these responses seem to be mediated partly through free radical reactions. For example, in magnetic sense and navigation using the geomagnetic field, one of the most promising mechanisms for explaining magnetic compass is "a radical pair mechanism". Biological free radicals are most commonly oxygen or nitrogen based with an unpaired electron, leading to the terms "reactive oxygen species (ROS)" or "reactive nitrogen species (RNS)". When applying SMF to medical treatment, coupling SMF exposure with possible chemotherapy of cancers is a novel fascinating area that SMF could enhance agent-induced ROS production against tumors. In addition, one of the potent mechanisms of SMF effects on hemodynamics and blood pressure has sometimes been linked to nitric oxide pathway. However, health and environmental concerns have been raised because the SMF effects on oxidative stress leading to genetic mutation and apoptosis/necrosis have been found. It seems to take place from free radical generation.