Dopamine negatively modulates NCA-1 and NCA-2 channel activity.

<p>(A) The <i>cat-2(e1112)</i> mutation suppresses the weak forward fainting phenotype of the <i>nlf-1(tm3631)</i> mutant. (***, P<0.001. Error bars = SEM; n = 40). (B) The <i>dop-3(vs106)</i> mutation suppresses the weak forward fainting phenotype of the <i>nlf-1(tm3631)</i> mutant. (***, P<0.001. Error bars = SEM; n = 40). (C) The <i>dop-3(vs106)</i> mutation partially suppresses the strong forward fainting phenotype of the <i>grk-2(gk268)</i>; <i>nlf-1(tm3631)</i> double mutant. (***, P<0.001. Error bars = SEM; n = 40). (D) Exogenous dopamine causes the <i>grk-2(gk268)</i> mutant to faint in a <i>dop-3</i> dependent manner. Shown is the percentage of animals that faint within a period of ten body bends when moving backwards after exposure to 2 mM dopamine for 20 min. (***, P<0.001. Error bars = SEM; n = 2–5 trials of 14–25 animals each).