Light Stimulation of the Sodium Pump in Epithelia

Abstract

WHEN pieces of isolated skin are exposed to intense flashes of light lasting less than 1 ms, an electrical response can be detected between electrodes placed on the two sides¹. This consists of a 1 ms initial response during which the anatomical inside surface of the skin is negative, followed by a slower series of waves of varying polarity but dominated by a component with a peak latency of usually 10–20 ms, positive inside (Fig. 1, +70 mV). In the previous report¹, this complex was termed the early response to distinguish it from a later response, a much slower transient alteration in potential lasting several seconds that was observed in frog skin. Both the early and late responses increase linearly with stimulus energy.