Picture from Kullyev A et al. (2010) Genetics "A genetic survey of fluoxetine action on synaptic transmission in ...."

Figure 1.Fluoxetine treatment and mutations in mod-5/ SERTabolish anti-5-HT immunoreactivity in the RIH and AIM neurons. (a-d) Photomicrographs of animals stained with anti-5-HT antibodies. To test the effects of MOD-5/SERT inhibitors, WT animals were incubated overnight on NGM plates containing 0.5 mg/ml of fluoxetine (as shown) or 0.4 mg/ml of imipramine (not shown) before fixation for staining. (e and f) Photomicrographs of WT animals expressing tph-1Tgfp. All the animals shown have anterior to the right.

Picture from Noble T et al. (2013) Cell Metab "An integrated serotonin and octopamine neuronal circuit directs the release of ...."

Supplemental Figure 4. atgl-1 control of serotonin-mediated fat loss, related to Figure 6. A. qPCR of endogenous atgl-1 transcripts in vehicle- and 5-HT-treated wild-type adults. 5-HT treatment significantly increases atgl-1 expression. Data are expressed as averages of quadruplicate determinations across two independent biological replicates + S.E.M. **, p<0.005. B. Addition of exogenous Oct (5mM; lower panel) did not change expression of the pATGL::GFP reporter relative to vehicle-treated animals (upper panel). C. Image of transgenic animal bearing a 7kb nhr-76 promoter fused to GFP shows expression in the intestine.

Picture from Noble T et al. (2013) Cell Metab "An integrated serotonin and octopamine neuronal circuit directs the release of ...."

Supplemental Figure 4. atgl-1 control of serotonin-mediated fat loss, related to Figure 6. A. qPCR of endogenous atgl-1 transcripts in vehicle- and 5-HT-treated wild-type adults. 5-HT treatment significantly increases atgl-1 expression. Data are expressed as averages of quadruplicate determinations across two independent biological replicates + S.E.M. **, p<0.005. B. Addition of exogenous Oct (5mM; lower panel) did not change expression of the pATGL::GFP reporter relative to vehicle-treated animals (upper panel). C. Image of transgenic animal bearing a 7kb nhr-76 promoter fused to GFP shows expression in the intestine.

Picture from Carnell L et al. (2005) J Neurosci "The G-protein-coupled serotonin receptor SER-1 regulates egg laying and male ...."

Figure 2. Rescue and expression pattern of ser-1. A, Rescue of the resistance to 5-HT- induced egg laying in ser-1 mutant animals in liquid. Three transgenic ser-1 strains containing the ser-1 open reading frame and a 7 kB upstream promoter (ser-1;egEx18[ser-1(+)], ser-1; egEx19[ser-1(+)], ser-1;egEx20[ser-1(+)]) showed a restored 5-HT-induced egg-laying re- sponse. The control strain (ser-1;egEx23[Pofm-1::gfp]) carrying an array containing only the coinjection marker, ofm-1::gfp, showed no rescue of the ser-1 mutant egg-laying behavior nor did the strain ser-1;egEx33[ser-1(+);Pofm-1::gfp] containing a 3.4 kB upstream promoter and ser-1 open-reading frame. Overexpression of ser-1 in a wild-type background (egEx18[ser- 1(+)]) behaved like wild-type for 5-HT-induced egg laying. Selective expression of ser-1 in muscles (ser-1;egEx26[Pmyo-3::ser-1(+)]) restored the 5-HT-induced egg-laying response. Single wild-type animals were placed into liquid M9 buffer containing 12.5 mM 5-HT for 90 min, and the number of eggs laid was counted. n = 24 for each group. Error bars indicate SEM. The asterisk indicates a statistical difference from ser-1 mutant animals ( p < 0.001), and the number sign indicates a statistical difference from wild-type animals (Mann-Whitney U test). B, C, Expression pattern of Pser-1::gfp in L1 hermaphrodite larvae. Pser-1::gfp(egEx21) contains an 8 kB upstream ser-1 promoter and is expressed in pharyngeal muscle, neurons in the head, ventral cord, and tail of L1 larvae. D, Expression of Pser-1::gfp(egEx21) in young adults. Pser-1::gfp is expressed in the vulval muscles in young adult hermaphrodites.

Picture from Hiebert T et al. (2017) MicroPubl Biol "Basal pharyngeal pumping elevated in C. elegans mod-5 mutants."

In C. elegans, the reuptake of serotonin (5-HT) is facilitated by mod-5, which encodes a 5-HT transporter that is orthologous to a human 5-HT transporter (SLC6A4). mod-5 has been shown to effect both feeding and locomotion in C. elegans (Ranganathan et al., 2001; Jafarau et al. 2011). We obtained and analyzed EPG data using a microfluidic device (NemaMetrix) for mod-5 null mutant strains, mod-5(n3314) (A, Exp 1 n=15; Exp 2 n=32) and mod-5(n822), (B, Exp 1 n=17; Exp 2 n=27) and N2 control worms (A, n=16 and 31; B, n=18 and 27 for Exp 1 and 2, respectively) in M9 saline buffer (2-minute recording duration). Mutations to the C. elegans serotonin reuptake transporter, mod-5, lead to an accumulation of serotonin at the synaptic cleft, which results in a significant increase in baseline pharyngeal pumping frequency in three out of four experiments (A, N2=0.10 ± 0.04 and 0.09 ± 0.03 Hz ; mod-5(n3314)=1.41 ± 0.44 and 2.26 ± 0.13 Hz; B, N2=0.98± 0.42 and 0.44 ± 0.08; mod-5(n822)=1.64 ± 0.33 and 3.76 ± 0.19 Hz; **p<0.005, ***p<0.0001, 2-tailed students t-test).

Picture from Cunningham KA et al. (2012) Cell Metab "AMP-activated kinase links serotonergic signaling to glutamate release for ...."

Figure 2. Serotonin from ADF Requires ser-5 in AVJ to Elevate Pumping (A) Wild-type pumping rate of tph-1 mutants in which tph-1 is reconstituted in ADF alone is dependent on ser-5 (ser-5;tph-1[Psrh-142::tph-1]), but not on ser-1 (tph-1;ser-1[Psrh-142::tph-1]) or ser-7 (tph-1;ser-7[Psrh-142::tph-1]). (B) ser-5 and hlh-34 are required for elevation of pumping rate in response to 5 mM 5-HT. Reconstitution of ser-5 within hlh-34-expressing neurons, but not pharyngeal neurons (Pglr-7::ser-5) or pharyngeal muscle (Pmyo-2::ser-5), confers responsiveness to 5-HT. Genetic ablation of hlh-34 neurons (Phlh-34::ICE) abrogates responsiveness to 5-HT. (C) Expression of Phlh-34::mcherry and Pser-5::ser-5::gfp overlap in hlh-34 neurons. Data are normalized mean ±SEM. For (A), ANOVA with Bonferroni correction for multiple comparisons. For (B), Student's t test. ***p < 0.001 versus well-fed animals, unless otherwise indicated. For (A) and (B), 2.5 kb upstream of the hlh-34 start site was used to drive expression of mCherry. Images were taken with a spectral confocal microscope using a Z-stack and compressed into a single file. WT, wild-type. See also Figure S2.

Picture from Srinivasan S et al. (2008) Cell Metab "Serotonin regulates C. elegans fat and feeding through independent molecular ...."

Figure 4. Expression Patterns of b-Oxidation Genes (A-H) Representative images of transgenic animals expressing GFP reporter fusions for promoters of the indicated genes. Inset panels show corresponding differential interference contrast images. (I) Change in transcript levels of the indicated metabolic genes upon 5-HT treatment in wild-type animals as determined by real-time qPCR. Data are reported as the average of two independent cDNA preparations +/- SEM.

Picture from Carnell L et al. (2005) J Neurosci "The G-protein-coupled serotonin receptor SER-1 regulates egg laying and male ...."

SER-1 is important for induction of ventral tail curling and male turning behavior. A, ser-1, mod-1, and mod-1;ser-1 mutant males are resistant to the effects of exogenous 5-HT on tail curling in liquid. Males were treated in M9 buffer containing 20 mM 5-HT for 15 min (5 animals per well), and the number of males with curled tails was counted. Transgenic ser-1 males expressing the ser-1 gene under its own promoter or under a muscle-specific promoter (myo-3) restore the tail-curling phenotype. Mutant males: n ≥ 9 trials for each genotype. Error bars indicate SEM. The asterisk indicates a statistical difference between N2 and mutant males; p < 0.001 (Student's t test). The number sign indicates a statistical difference between ser-1 and mod-1; p < 0.001 (Student's t test). B, Expression pattern of Pser-1::gfp(egEx21) in males. In addition to neuronal expression observed in hermaphrodites (bright staining in the tail), fainter expression in the male diagonal muscles (arrows) is observed. C, Turning behavior of ser-1, mod-1, and mod-1;ser-1 males. Average percentage of good, sloppy, and missed turns per individual male is shown. n = 20 for each genotype. The percentage of good turns is statistically different between wild-type N2 and mutant males ( p < 0.001; Student's t test) and between ser-1 and mod-1;ser-1 mutant males ( p < 0.001; Student's t test). D, Male mating efficiency of wild-type, ser-1, mod-1, and mod-1;ser-1 and tph-1 mutant males. A single unc-13 L4 hermaphrodite was placed onto an agar plate with a single L4 mutant male. The number of cross progeny was determined by counting the number of non-Unc animals that were produced from the mating. n = 50 for number of mating plates examined.

Picture from Lee RC et al. (2001) Science "An extensive class of small RNAs in Caenorhabditis elegans."

Figure 1. Northern blots of small RNA transcripts. (A through C) Total RNA from C. elegans larvae (stages L1 through L4) or from mixed stage (M) populations were blotted and probed with oligonucleotides complementary to either the 5' or 3' half of the indicated transcript (13). U6 = the same filters were probed with probe to U6 snRNA as a loading control. (A)mir-60 5' probe detects a transcript of ~65 nt. The ratio of L1 to L4 mir-60 signal, normalized to U6, is about 5:1. The mir-60 3' probe (not shown) detects a similar-sized species with a similar developmental profile. (B) mir-80 3' probe detects a ~22-nt RNA expressed uniformly at all stages. (C) mir-52 5' probe. The normalized mir-52 signal is threefold greater in the L1 versus the L3. (D) mir-1 3' probe detects a transcript of ~22 nt in total RNA from mouse (Mm) 17-day embryos, mixed-stage C. elegans (Ce), Drosophila melanogaster (Dm) mixture of embryo-larvae-pupae, and in a sample of human heart (ht) tissue. Other human tissue samples were brain (br), liver (li), kidney (ki), and lung (lu). (E)mir-1 and mir-58 probes to total RNA from mixed populations of wild-type (+) and dcr-1(ok247) (-) animals. An increase in the proportion of unprocessed ~65-nt precursor is observed in the dcr-1 RNA.

Picture from Hiebert T et al. (2017) MicroPubl Biol "Reduced pharyngeal pumping rates observed in tph-1 mutants using microfluidic ...."

In Caenorhabditis elegans, serotonin (5-HT) activates and controls pharyngeal pumping in response to food (Horvitz et al., 1982; Sze et al., 2000; Song and Avery 2012). Tryptophan hydroxylase, the enzyme required for serotonin biosynthesis, is encoded by the gene tph-1. Worms with a tph-1 deletion mutation exhibit phenotypes associated with a lack of serotonin-signaling, including reduced pharyngeal pumping (Sze et al., 2000; Avery and Horvitz 1990; Song and Avery 2012). We used a microfluidic electropharyngeogram (EPG) recording platform (NemaMetrix) and associated software (NemAnalysis) to measure pharyngeal pumping in C. elegans tph-1 mutants in the presence of bacterial food (100 mg/ml E. coli OP50 in M9 buffer), following a 2-hr fasting period. Prior research has shown that a fasting period (e.g., 2-4-hr) induces elevated feeding rates for worms upon re-introduction to bacterial food (Lemieux and Ashrafi 2015). We chose to measure pharyngeal pumping during this elevated feeding phase due to our hypothesis that tph-1 animals would exhibit lower pumping rates than control worms. Pumping was recorded for 2-minute durations over three independent trials (total N2 n = 90; tph-1 n = 92). C. elegans tph-1 mutants exhibited significantly lower pharyngeal pumping rates than N2 control animals (A, N2 = 3.46 ± 0.19 Hz; tph-1 = 0.89 ± 0.10 Hz; mean ± SEM; *** p < 0.0001, 2-tailed students t-test). Pumping frequency data were pooled in A; see B for a comparison of each experimental trial.