Figure 3.
Example of the most commonly observed C-fiber comprehensive phenotype in the GDNF-OE preparations. a, This sensory neuron had a broad inflected somal action potential and was characterized as a low-threshold mechanoreceptor by its vigorous response to a very small force applied using a calibrated (0.07 mN) von Frey filament. It also responded vigorously to noxious heating of the skin, which is characteristic of a heat nociceptor. b, Neuron characterized in a was IB4 (red) and P2X3 (blue) positive. The bottom panel shows triple-label overlap. c, Dorsal horn termination of C-fiber shown in a and b. Dotted lines show the outline of the dorsal horn and the boundary between laminas II and III. d, High-power view to show fiber arborization in laminas I–II outer. Note that this fiber exhibited after discharge after the heat stimulus.