Journal of Applied Physiology, Vol 65, Issue 1 124-130, Copyright © 1988 by American Physiological Society
Effects of pulsed electromagnetic fields on Na+ fluxes across stripped rabbit colon epithelium
C. S. Collis and M. B. Segal
Sherrington School of Physiology, St. Thomas's Hospital Medical School, London, United Kingdom.
The effect of pulsed electromagnetic fields on the electrical potential and
two-way flux of Na+ across the epithelium of the rabbit colon in vitro was
investigated. In control experiments the transepithelial mucosal-to-serosal
and serosal-to-mucosal fluxes (Jm----s and Js----m) were constant over the
experimental period. When the epithelium was at right angles to the applied
electromagnetic field, the Jm----s flux of Na+ was reduced, whereas Js----m
was enhanced. When the epithelium was rotated 180 degrees, Jm----s was
enhanced, whereas Js----m was reduced. When the epithelium was mounted
parallel to the magnetic field, both Jm----s and Js----m of Na+ were
increased, the latter continuing to increase after the field was turned
off. When the tissue was rotated 180 degrees, the same enhanced flux was
observed, but now the Jm----s flux showed the greatest increase, which
again occurred in the period after the field was turned off. The rate of
decrease of transepithelial potential difference in all orientations was
less than the control. Also, the conductance increased in orientations 2-4
and decreased in orientation 1 after the field had been applied. This
suggests that pulsed electromagnetic fields can have a direct effect on the
movement of Na+ across tissue and transepithelial potentials. The mechanism
may depend on several factors, such as induced changes in certain ion
pumps, the membrane potential, and the surface charge of cell wall
proteins.
