Figure 7. Agonist equilibrium/peak relationship. A, Membrane currents elicited by Glu (10 mm), KA (1 mm), AA (40 mm), and Dom (50 μm) in an outside-out patch expressing GluK2 receptors. Peak responses in each case were normalized to allow comparison (patch number 060207p2). B, Left, Summary plot showing that there is an approximate inverse relationship between peak (abscissa) and equilibrium (ordinate axis) GluK2 agonist responses in NaCl (open circles) and in NaI or NaNO3 (gray triangles). Each point represents a specific agonist from this study (see Table 1) or from that by Fay et al. (2009). The solid line is a fit of the NaCl data using Eq. 2 (n = 1.67, k = 1866, C = 0.01). Right, Summary plot showing the inverse relationship in NaCl (black line from NaCl fit on the left) and in KCl or RbCl (light gray squares). The light gray line is a fit of the K+ and Rb+ data using Eq. 2 (n = 1.8, k = 760, C = 0.1).