Article Figures & Data
Figures
- Figure 1.
Cultured DRG cells from all rostrocaudal levels at E11.5, E12.5, and E14.5 stained with the general nuclear marker propidium iodide (A′–C′, red) and for the neuronal marker βIII-tubulin (A″–C″, green; A‴–C‴, merged), showing the gradual increase in neuronal differentiation. Scale bar, 50 μm. D, Quantification of A–C (n = 3). E, mRNA levels of the neuronal marker UCHL1, normalized against the adult.
- Figure 2.
Representative recordings of calcium transients in DRG neurons at different developmental stages in response to cold, TRP channel agonists, and KCl. CA, Cinnamaldehyde; Cap, capsaicin; T, temperature.
- Figure 3.
A, Proportion of DRG neurons responding to TRP channel agonists and cold stimulus. B, Reverse transcription-PCR gels of TRPV1, TRPM8, and TRPA1 illustrating the onset of mRNA expression in the developmental stages (n = 5–8). The onset of functional responses coincides with the onset of mRNA. C–E, Quantitative reverse transcription-PCR (n = 4) for TRPV1 (C), TRPM8 (D), and TRPA1 (E). AD, Adult; CA, cinnamaldehyde.
- Figure 4.
A, Representative Ca2+ transients in response to TRP channel agonists in different sensory neuron subtypes. B, Pie charts showing the distribution and overlap between the different responses during the developmental stages. C, Plot of the menthol-responsive cells and their response to capsaicin, showing a significant loss of capsaicin sensitivity between stages P0 and P14. *p < 0.05. CA, Cinnamaldehyde; Cap, capsaicin; Men, menthol.
- Figure 5.
A, Vital staining with isolectin B4 (IB4; green) of dissociated DRG neurons from stages E18.5 and P14, showing preferential staining of small-diameter neurons and lack of staining in large-diameter neurons (asterisks). Scale bar, 50 μm. B, Percentage of IB4-binding neurons at different developmental stages. C, Pie chart showing the functional responsiveness in relation to IB4 staining. Note the virtual absence of menthol responses and the late onset of a large proportion of cinnamaldehyde-responsive neurons within the IB4+ population. D, Graph showing the amount of cinnamaldehyde-responsive cells in relation to IB4 staining, showing a significant increase of cinnamaldehyde sensitivity between P14 and adult in the IB4-positive population. CA, Cinnamaldehyde; Cap, capsaicin; Men, menthol; neg, negative; pos, positive.
- Figure 6.
Proposed model of the developmental relationship between the different sensory neuron subtypes. At E11.5, TRP-negative cells (gray) acquire TRPV1 (red) until the peak at E14.5, after which some cells will downregulate TRPV1. These cells give rise to the TRPV1−, IB4+ cells and some of the TRPV1−, IB4− cells. Before birth, at E18.5, the cells expressing TRPM8 (green and brown) are specified from within the TRPV1-positive population. Some cells subsequently downregulate TRPV1, giving rise to two populations of TRPM8-positive neurons (with or without TRPV1; brown and green, respectively). Within the IB4-negative population, the TRPA1-positive cells derive from TRPV1-positive neurons perinatally, whereas within the IB4-positive population, the TRPA1-expressing cells arise >2 weeks later. Some of the TRPA1- and TRPV1-coexpressing cells (orange) will also downregulate TRPV1, giving rise to TRPA1-only neurons (yellow). A1, TRPA1; M8, TRPM8; neg, negative.
Additional Files
Supplemental Data
Files in this Data Supplement:
- supplemental material - Figure legends
- supplemental material - Figure 1
- supplemental material - Figure 2
