The vibrating probe detects small currents around organs or organisms. Outward currents (net flow of positive charges) are observed at the equator of the lens and inward currents are observed at the optical poles. Ouabain has a limited effect on the currents. They are diminished but adding K+ and by removing Na+ from the medium. Therefore, they are predominantly passive currents with the electrochemical gradients serving as the driving force. There is some suggestion that the currents at the equator may incude an active component associated with the efflux of Na+. If established, such an active outward current at the equator would represent a new finding with possible important implications for understanding lens physiology and cataractogenesis because of the special role of the equator as the site of fiber formation and elongation. An apparatus has been set up to simultaneously measure currents with the vibrating probe and potential differences across the lens membranes. By correlating the findings of these two electrical measurements with different types of perturbation, it will be possible to advance our understanding of the nature of currents around the lens.
