1. Peripheral terminals of Trpm8GFP axons are found in functionally distinct regions in the tooth. a, Schematic diagram of mouse molars indicating the termination zones of cold-sensitive C- (red) and Aδ-fibers (green) localized in the pulp and dentin, respecti...
Peripheral terminals of Trpm8GFP axons are found in functionally distinct regions in the tooth. a, Schematic diagram of mouse molars indicating the termination zones of cold-sensitive C- (red) and Aδ-fibers (green) localized in the pulp and dentin, respectively. Cell rich odontoblast layer that separates the pulp and dentin is shown in blue (blue box). During a cold stimulus, C- and Aδ-fibers fire with distinct rates of discharge, latencies, and adaptation, as depicted in green box [schematic and data modeled after that of Byers and Narhi (2002) and Jyvasjarvi et al. (1987), respectively]. b, In a longitudinal section of a decalcified molar, Trpm8GFP fibers (green) cross the odontoblast layer located at the pulp–dentin border (dashed line) and extend into the dentin (arrowheads). Cell nuclei were stained with DAPI (blue). c, d, Immunostaining of mouse molars reveals Trpm8GFP axons are morphologically and neurochemically distinct. c, Colabeling of Trpm8GFP (green) and CGRP (red) axons in mouse molars show that both fiber types have asymmetrically distributed terminals that reside in the pulp (arrows in boxed region) and extend into the dentin (arrowheads). d, Peripherin fibers (red) extend to, but do not enter the odontoblast layer (boundary marked by arrowheads), whereas Trpm8GFP fibers (green) extend through and into the dentin (arrows).
Yoshio Takashima et al. J. Neurosci. 2007;27:
©2007 by Society for Neuroscience