Expression of ple^Scer\UAS.cNa under the control of Scer\GAL4^elav-C155 during late embryogenesis results in depressed feeding behavior in larvae. There is no change in pupal size for these mutants and no change in time to pupariation, but there is a direct correlation between the extent of knockdown and the number of pupae. Locomotor behavior is normal in these flies. The 5-HT axonal fibers projecting to the gut from the larvae, with increased neuronal DA levels due to ple^Scer\UAS.cNa expression, display greater complexity relative to controls: increased fiber branching, increased number of 5-HT-containing vesicles along the axon length, and greater numbers of larger vesicles. There is no change in pupal size for these mutants and no change in time to pupariation, but there is a direct correlation between the extent of overexpression and the number of pupae.

Expression of ple^Scer\UAS.cNa in 2nd instar larvae, under the control of Scer\GAL4^{elav.Switch.PO} does not affect feeding behavior, locomotion or gut fiber architecture. Branching, varicosity number, varicosity area and the number of large varicosities are unaffected.