3H-noradrenaline release potentiated in a clonal nerve cell line by low-intensity pulsed magnetic fields

Abstract

Recent studies have shown that extremely low-frequency (ELF) electric fields1 and radiofrequency amplitude-modulated electromagnetic fields2,3,25 can influence ion fluxes in neural tissue. Furthermore, the application of low-frequency magnetic (LFM) fields in the successful treatment of non-union fractures and pseudo-arthrosis has been widely reported4–6. Stimulated by these findings and the wide variety of effects reported in other biological systems7–10, we have set out to establish a model system for studying the biological effects of such low-frequencyfields that readily allows analysis of their mechanism of action. Clonal lines in tissue culture are an obvious choice for such a model, first, because the analysis is simplified by the presence of only one cell type and second, because the geometry of the biological sample can be specified to allow precise quantitation of applied field strengths and induced current densities. One such clonal line, designated PC12, is a likely candidate for such an approach as it expresses many properties of differentiated sympathetic neurones11–16, including calcium-dependent release of newotransmitters11,12,14. We report here that 3H-noradrenaline(NA) release from PC12 cells is stimulated by an inductively coupled 500-Hz LFM field with a magnitude comparable with certain cholinergic stimuli in this system.