Adenosine triphosphate (ATP) in the MCF-12A epithelial cell: Square wave (150 Hz pulsed saw tooth-like waveform) versus AC electric stimulation in vitro

Abstract

Electrotherapy has been used for a variety of clinical conditions with varying results. In 1982 it was shown that a small DC current leads to an increase in ATP generation. ATP has been implicated as a peripheral mediator of pain. This study compared the effects of an AC TENS (transcutaneous electric nerve stimulation) device to a DC operated MET (micro-current electric therapy) device, on ATP levels in cultured cells. MCF-12A epithelial cells were exposed to either a 600 μA micro-current DC field or a mA current AC field. Intracellular and extracellular ATP levels were measured by chemiluminescence. Extracellular ATP secretion from MCF-12A cells was found to be 27.7-fold after micro-current DC treatment, compared to 2.5-fold after conventional AC treatment. However, neither electric modality resulted in net ATP production. Cell morphology was not affected by either strategy. A hypothesis for the mechanism of micro-DC in pain modulation is proposed, whereby extracellular ATP is degraded to adenosine, a strong analgesic agent.