Figure 5: Octopamine and the SER-3 receptor transduce ASH inhibition to ASIs.

(a) The specific expression of TeTx in ASH neurons achieved by the use of FLP–FRT site-specific recombination system and R-GECO1 in ASI neurons directed by the gpa-4 promoter. Scale bars, 20 μm. (b) Genetically silencing and optogenetically inhibiting ASHs resulted in a big on-response of Cu²⁺-evoked Ca²⁺ response in ASI neurons. (c) The ser-3 lof mutation had a similar effect on the ASI response to the 10 mM CuSO₄ stimulation as silencing ASHs with TeTx, which could be rescued by extrachromosomal expression of the gene driven by its own or an ASI-specific promoter. (d) The expression patterns of ser-3p::ser-3::sl2-GFP and gpa-4p::R-GECO1 in ser-3-null animals. These genes were co-expressed in ASI neurons. (e) The bending magnitude of the Cu²⁺ avoidance in wild type, mutant and transgenic worms (n=30 assays). All data are expressed as means±s.e.m. The number on each bar indicates the number of independent tests for each genotype. One-way analysis of variance (ANOVA) test in b,c and two-way ANOVA test in e. Corrected with Bonferroni t-test. Values that differ significantly are indicated (*P≤0.05, **P≤0.01 and ***P≤0.001 compared with the wild-type N2 control).