Galvanotropic and galvanotaxic responses of corneal endothelial cells

The effects of weak electric fields (E-fields) on cultured rabbit corneal endothelial cells were studied. The cells responded to steady E-fields (2-6 V/cm) by elongating their somata 90 degrees to the field (galvanotropism) and by migrating (galvanotaxis) towards the anode. During these directional movements, pseudopodia and ruffled membranes formed preferentially on the anodal side of the cells, while they retracted on the cathodal side. Fluorescent labelling for actin showed many stress fibers aligned parallel to the long axes of the elongated cells and few aligned toward the anodal direction. Fluorescent labelling for vinculin showed the abundance of cell-to-substratum adhesion foci at the termini of the stress fibers. Galvanotropic and galvanotaxic cellular movements were inhibited by cytochalasin D (0.1-0.5 microgram/mL) and the calmodulin antagonist, W-7 (80 mumol/L). These results suggest that E-field induced directional movements of corneal endothelial cells constitute a calmodulin-dependent, active (not passive) process.