Physical Mechanisms for Biological Effects of Low Field Intensity ELF Magnetic Fields

摘要: Biological effects of high intensity ELF electric fields, such as muscle stimulation and - at still higher intensities cell damage by electroporation heating, are reasonably well (although not completely) understood. However power frequency magnetically induced fields less than 10 -3 V/m or alternating magnetic about 100 μT cannot be explained very the present time. The biological processes involved, notably signal transduction membrane subsequent biochemical involving “second messengers” beginning to identified (Adcy, 1990; Luben, 1993). These involve vast amplification incident “signal” with metabolically supplied energy. physical mechanisms conversion from an field process however unknown As a consequence we do know which aspect applied environment is important. Properties polarization, duration and/or intermittency signal, harmonic content may turn out important amplitude. biological, chemical mechanical condition organism (e.g. stage in cycle, mitogen density) will also influence effectiveness field. A key question, only resolved for few experimentally observed effects, whether specific results arc caused directly that tissue time varying Particularly larger direct “magne-tochemical” have been suggested presence magnetite particles some tissues play role. Experimental findings suggest particularly likely when their magnitudes level relatively “large”, order 10-3 larger, (McLeod et al., 1993b; Liburdy, 1992; Lyle 1988), multiple cells connected gap junctions. Induced affect motion “counterions” on surface possibly structural fluctuations nucleic acid molecules. While most proteins small net electrostatic charge, acids polyelectrolytes large charge surrounded counterions (McCammon Harvey, 1987). view inefficiency induction field, illustrated equation (25). “direct” interaction need serious consideration. This necessary produce unambiguous amplitude orientation (in relation culture medium animal) fields. relative magnitude direction static (such earth) can determine simultaneously systems under controlled laboratory conditions.