Effect of intracellular perfusion with La3+. Lanthanum was included in the electrode-filling solution at a concentration of 100 µM, and repetitive photostimulation (one flash/min) started immediately after accessing the cell interior. (A) Normalized average amplitude of the photocurrent in Joseph cells dialyzed with 100 µM lanthanum (closed symbols), compared with control solution (open symbols). No significant differences over time were observed between the two conditions (n = 3 in each group). (B) Similar experiment in a Hesse cell, extending the recording period to 9 min. Raw traces of the photoresponse are shown as insets. (C) Bar graph summarizing the effect of intracellular lanthanum on response sensitivity. The average light intensity required to elicit a response of half-maximal amplitude is plotted for Joseph and Hesse cells tested under the two conditions of intracellular perfusion.
