Figure 1. Exogenous serotonin reduces LRO Nile red.

(A) Exogenous serotonin suppresses LRO Nile red in a dose dependent manner. Animals were treated for 48 hours with doses indicated. (B) A representative image of an animal treated with 5 mM serotonin shows near complete absence of LRO Nile red. (C) Mutants lacking serotonin do not have a large effect on LRO Nile red. A null mutant in tph-1 (tryptophan hydroxylase) causes a modest decrease in LRO Nile red whereas a null cat-4 mutant (GTP-cyclohydrolase) which lacks dopamine and serotonin has a small but significant increase in LRO Nile red. cat-2 mutants have defective dopamine production but preserve normal serotonin synthesis. (N>25; significance by ANOVA with Bonferroni correction.)