Figure 4.

Varying extracellular Na⁺ concentration causes a Nernstian shift in the reversal potential of the peak acid-evoked current in rat retinal ganglion cells. Ai-Aiii, Current–voltage relationships (normalized in terms of current density) measured in three different concentrations of extracellular Na⁺ as indicated in the figure (n = 9, 5, and 5 for decreasing [Na⁺]_o). B, Comparison of mean-measured reversal potentials adjusted for ionic activity (squares; ±SEM) and theoretical reversal potentials for channels conducting Na⁺ alone derived using the Nernst equation (dashed line).