FIGURE 10.

Mutations at the base of the selectivity filter abolish agonist activation. (A) Typical current traces recorded during voltage pulses from −130 to +40 mV from wild-type (ATAT/SASA) and mutant (VVVV/SASA) and (ATAT/LLLL) channels in the absence and presence of 10 μM dopamine. Agonist-activated currents (obtained by subtracting currents in the absence and presence of agonist) are also shown. (B) Mean normalized current-voltage relationships of each channel in the absence (−) and presence (+) of agonist and the agonist-activated (a-a) current. Mean ± SE shown (n = 7).