Figure 1: Serotonin activates axon regeneration.
From: Axotomy-induced HIF-serotonin signalling axis promotes axon regeneration in C. elegans
(a) The synthesis of serotonin from tryptophan catalyzed by TPH-1. (b) Representative PLM sensory neurons in wild type and tph-1 mutant animals 24 h after laser surgery. Arrowheads indicate cut sites. Scale bar=20 μm. (c) Regeneration of PLM sensory neurons. Lengths of PLM regrowth at 24 h after laser surgery are shown. Error bars indicate s.e.m. ***P<0.001 (n≥30; unpaired t-test, two-tailed and unequal variances). (d,f) Regeneration of D-type motor neurons. Percentages of axons that initiated regeneration 24 h after laser surgery are shown. Error bars indicate 95% CI. ***P<0.001; **P<0.01; *P<0.05; NS, not significant (Fisher’s exact test, two-tailed, n≥50). (e) Cell-specific deletion of tph-1 using a Cre-loxP recombination system. CI, confidence interval.
