RECTIFICATION AND SIGNAL AVERAGING OF WEAK ELECTRIC-FIELDS BY BIOLOGICAL CELLS

Oscillating electric fields can be rectified by proteins in cell membr anes to give rise to a de transport of a substance across the membrane or a net conversion of a substrate to a product. This provides a basi s for signal averaging and may be important for understanding the effe cts of weak extremely low frequency (ELF) electric fields on cellular systems. We consider the limits imposed by thermal and ''excess'' biol ogical noise on the magnitude and exposure duration of such electric f ield-induced membrane activity. Under certain circumstances, the exces s noise leads to an increase in the signal-to-noise ratio in a manner similar to processes labeled ''stochastic resonance.'' Numerical resul ts indicate that it is difficult to reconcile biological effects with low field strengths.