The responses of cells to electrical fields: a review.

Abstract

The application of DC electric fields to cells has a long and contentious history.The interpretation of the response of cells to such fields was hampered by lack of adequate recording technique, contamination of cultures by electrode products, uncertainty about the magnitude of fields, and sometimes by the complexity of the biological system under study.Nevertheless, when Jaffe and Nuccitelli (12) reviewed the literature in 1977, they found eight reliable reports of the response of plant cells to applied fields and four of animal cells.Since then, several laboratories have applied electrical fields to isolated cells in culture and recorded the responses on film or video tape so that responses could be characterized carefully and the threshold field strengths established.In these later studies, the size and direction of the fields are known unambiguously and possible artifacts such as electrode products, nutrient gradients, flow effects, and temperature changes are controlled.The significance of these recent results is increased by the finding that several cell types that normally migrate or grow long distances in embryos respond directionally to surprisingly small fields (Table I), and by the concurrent finding that developing embryos produce substantial endogenous currents.These two facts raise the possibility that endogenous electrical fields are involved in long-range signalling during embryonic development and during certain responses to injury.I review here the recent literature on the responses of isolated cells to small electrical fields, discuss possible mechanisms by which cells might sense these small fields and, finally, consider the physiological relevance of these responses.