Figure 9.
Effects of removal of extracellular Ca on adaptation. (A) The response to 100-ms test flashes delivered in the dark or superimposed upon a 5-s background light was examined in standard ASW (left) and after superfusing the cell with Ca-free solution (right). The amplitude of the photocurrents increased in 0-Ca, but in both conditions the incremental flash response decreased as the background light intensity increased (insets). (B) Peak amplitude of the incremental responses normalized with respect to the dark-adapted value, plotted as a function of the attenuation of the background light. The relative reduction of sensitivity induced by the adapting light did not differ significantly in the two conditions. Test flash intensity: 16 × 1015 photons · cm−2 · s−1; unattenuated background intensity: 4.2 × 1015 photons · cm−2 · s−1.