FIGURE 11.

Change in selectivity during agonist activation. (A) Typical current traces from the wild-type channel with K⁺ (left) or Rb⁺ (right) as the charge carrier in the absence of dopamine (top), in the presence of 10 μM dopamine (middle), and after the subsequent addition of 1 mM Ba²⁺ (bottom). (B) Typical current traces recorded from an uninjected oocyte with K⁺ (left) or Rb⁺ (right) as the charge carrier in the presence of 10 μM dopamine. In A and B, currents were recorded during voltage pulses from −130 to +40 mV and arrows indicate zero current. (C) Mean normalized current-voltage relationships with K⁺ or Rb⁺ as the charge carrier and with (+) and without (−) dopamine. Mean ± SE shown (n = 7). Ba²⁺-sensitive currents shown.