203 - Possible Mechanisms of Weak Electromagnetic Field Coupling in Brain Tissue☆

Abstract The effects of weak electromagnetic fields have been tested on the efflux of calcium from cerebral tissue of chick and cat. The data strongly suggest that the binding and release of calcium occurs cooperatively as the result of long—range interactions between anionic charge sites on the binding substrate. Extremely low frequency (ELF) fields at frequencies of 6 and 12 Hz and gradients in air of 0.1 to 0.5 V/cm decreased calcium efflux by 12 to 15 per cent. Higher and lower frequencies were without significant effect. For chick tissue, the field threshold in air was 0.1 V/cm and for the cat around 0.6 V/cm. At intensities above and below these levels, effects became statistically insignificant. With 147 MHz amplitude modulated fields, calcium efflux from chick cerebral tissue increased for modulation frequencies from 6 to 20 Hz, with a maximum of more than 15 per cent. No significant changes occurred at higher or lower modulation frequencies, nor with an unmodulated carrier wave. With 450 MHz fields amplitude modulated at 16 Hz, increased calcium efflux from chick cerebral tissue occurred at field intensities between 0.1 and 1.0 mW/cm 2 . No increase was noted above or below these levels. This series of amplitude and frequency windows is discussed in relation to possible modes of cooperative organization of cell membrane surface glycoproteins in the binding and release of calcium.