An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes

Abstract

Purpose: This study aimed to determine whether Terrestrial Trunked Radio (TETRA) fields can affect intracellular calcium signalling in excitable cells.

Materials and methods: Intracellular calcium concentration ([Ca^{2 +} ]_i) was measured in cultured rat cerebellar granule cells and cardiac myocytes during exposure to TETRA fields (380.8875 MHz pulse modulated at 17.6 Hz, 25% duty cycle). [Ca^{2 +} ]_i was measured as fura-PE3, fluo-3 or fluo-4 fluorescence by digital image analysis.

Results: Granule cells exposed at specific absorption rates (SARs) of 5, 10, 20, 50 or 400 mW · kg⁻¹ showed no significant changes in resting [Ca^{2 +} ]_i. Increases in [Ca^{2 +} ]_i in response to potassium-induced depolarization were significantly different from sham controls in TETRA-exposed cells, but the majority of the difference was attributable to initial biological variation between cell cultures. No difference was found between fura-PE3 (UV excitation) and fluo-3 (visible light excitation) measurements in these cells. Exposure to TETRA (50 or 400 mW · kg⁻¹) had no significant effect on either the rate or amplitude of spontaneous Ca^{2 +} transients in cardiac myocytes. The cells showed normal responses to salbutamol (50 μM) and acetylcholine (10 μM).

Conclusions: Overall, these results showed no evidence of any consistent or biologically relevant effect of TETRA fields on [Ca^{2 +} ]_i in granule cells and cardiac myocytes at any of the SAR tested.

Keywords:

• Electromagnetic fields
• TETRA
• biological effects
• calcium signalling
• heart
• brain