PEMF, Direct Current and Nedronal Regeneration: Effect of Field Geometry and Current Density

Abstract

Sensory ganglia from 7-8 day chick embryos were exposed to pulsed electromagnetic fields (PEMF) or direct current(DC) in order to correlate stimulation of neurite outgrowth with current density as a function of field geometry. Growth scores were obtained on ganglia growing in the inner and outer rings of 50 mm culture dishes. Control cultures and cultures treated with nerve growth factor served as standards. In PEMF experiments with the coil pair oriented horizontally, no correlation was observed between ganglia growth and current density in contrast to our previous findings with the coils oriented vertically. Comparison of current density for vertical and horizontal coils driven identically suggests a dose-saturation effect for the induced current with a threshold at approximately 0.4 uA/cm². Application of DC elicited significantly greater growth as a function of location with current density levels above 9 nA/cm². Interestingly, the total charge input for PEMF and DC stimulation was nearly identical, 10⁻³ coulombs.