Radiofrequency Radiation Effects on Excitable Tissues

Abstract

Abstract : Spheroidal aggregates of cultured chick cardiac cells were used to study effects of 2450-MHz radiofrequency radiation (RFR) on excitable membranes. Membrane voltage noise was recorded simultaneously with two microelectrodes. Preparation bulk temperature ws 37 + or - 0.2 C, and temperature at the aggregate was less than 0.9 C above this during RFR exposures of 2- and 3-min durations. Specific absorption rate (SAR) was between 1 and 231 mW/g, and both continuous-wave (CW) and pulse-modulated (PW, 5 mcirosec at 100 pps) RFR were applied using an open-ended coaxial exposure device. Membrane voltage fluctuations, in the form of noise and microspike event and membrane impedance were observed before, during, and after RFR exposures. No RFR effect was seen on membrane impedance viewed as parallel resistance and capacitance. The relation of membrane voltage noise power (0.1-1.0 Hz) to membrane potential was significantly altered during the first half of 3-min exposures to 1-5 and 15-30 mW/g CW RFR. This was found by using two-tailed t-tests to test the difference in slopes between least-squares linear regression fits of data from different RFR conditions with the significance level set at P0.05. Although microspikes seemed to contribute to this RFR effect on noise, there was no significant difference (two-tailed t-test, P0.05) in frequency of occurrence of microspikes greater than 0.2 mV for any RFR exposure condition.