Fig. 5

a Microphotographs and analysis show that nicotine and gabazine increased the her4.1⁺ (green)/BrdU⁺ (magenta) cells, whereas GABA reduced the number of her4.1⁺/BrdU⁺ cells in the examined spinal hemisegment (P < 0.0001). b In vivo administration of ACh, muscarine, nicotine, and gabazine increased the number of BrdU⁺ cells per hemisegment (P < 0.0001). Administration of GABA reduced the number of BrdU⁺ cells in the adult zebrafish spinal cord hemisegment (P < 0.0001). c Co-administration of nicotine and gabazine generated the same number of BrdU⁺ cells as the individual administration of nicotine or gabazine. Co-activation of the nicotinic-ACh receptors and the GABA_A receptors produced the same number of BrdU⁺ cells as in control (saline; P < 0.0001). d Application of ACh induced currents of the same frequency and amplitude in NSPCs before and after training, suggesting no changes in the cholinergic receptors following training. e Bath application of GABA before and after training revealed a significant reduction of the tonic activation amplitude without affecting its duration in the NSPCs. ACh, acetylcholine; BrdU, 5-bromo-2ʹ-deoxyuridine; GABA, γ-aminobutyric acid; GFP, green fluorescent protein; her4.1, hairy-related 4, tandem duplicate 1; The dashed gray line represents the baseline. Data are presented as mean ± s.e.m., as violin plots and as box plots showing the median with 25/75 percentile (box and line) and minimum–maximum (whiskers). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; ns, not significant. For detailed statistics, see Supplementary Table 1.