Calcitonin gene-related peptide- and substance P-immunoreactive nerve fibers in Meissner's corpuscles of rats: an immunohistochemical analysis.

The present study demonstrates that about 15% of the Meissner's corpuscles (MCs) of the rat glabrous skin of the feet contain one to two fibers immunoreactive for calcitonin gene-related peptide (CGRP), and that these fibers originate from the dorsal root ganglion. Double immunofluorescent cytochemical investigation has revealed that almost all the CGRP-immunoreactive (CGRPI) fibers in the MCs were immunoreactive for substance P. Subsequent immunoelectron microscopic analysis has demonstrated that the CGRPI fibers in the MCs are unmyelinated. In the course of passage through the MCs, no synaptic contact between the CGRPI fibers and underlying cells or non-CGRPI fibers was found.