Figure 4. The dopamine receptor DOP-1 is required in DVA for NLP-12 modulation of food searching. (A) Frequency of high angled reorientations for wild type and
nlp-12(
ok335) animals quantified for 5 minutes after transfer to food free plates in the presence (+) or absence (2) of dopamine (DA). Bars represent mean (6SEM) for at least 12 animals. Dopamine mechanosensory signaling is strongly enhanced at low osmotic strength [73]. Therefore, these assays were conducted following transfer of the animals to low osmotic-strength assay plates as described previously [14]. We observed a modest increase in basal reorientation frequency across all genotypes under these conditions. (B, C) Representative images (B) and quantification (C) of NLP-12::VenusYFP fluorescence in the ventral cord region of the DVA process of wild type,
dop-1(
vs100), and
dop-1(
vs100) Ex DVA::
dop-1 animals before (2) and after (+) 10 minutes dopamine (DA) treatment (wild type: n = 12 for (2) and (+) DA;
dop-1(
vs100): n = 12 for (2) and 9 for (+) DA). Ex DVA::
dop-1 refers to specific rescue of
dop-1 expression in DVA using the
nlp-12 promoter (2DA, n = 12; +DA, n = 11). Bars represent mean 6SEM. ***, p,0.0005; *, p,0.05 student's t-test. (D) Single slice confocal images of the DVA neuron in a transgenic animal expressing
nlp-12::SL2::mCherry (upper panel) together with Pdop-1::GFP (middle panel). White arrow denotes the DVA interneuron in all cases. Asterix denotes a ventral cord motor neuron expressing the
dop-1 reporter. Scale bars in B and D, 20 um. (E) Total directional reorientations measured during 0-5 and 30-35 minute intervals following removal from food for the genotypes as indicated. WT: n = 10;
dop-1(
vs101): n = 12,
dop-1(
vs100): n = 14,
dop-1(
vs100) Ex DVA::
dop-1: n = 12 and
dop-3(
vs106): n = 8. Bars represent mean (6SEM). For (A) and (E) ***, p,0.0005, **, p,0.005 by ANOVA with Sidak's post-hoc test.