Role Of Meissner Corpuscles In Tactile Potential Generation

Abstract

Sensory potentials evoked by a physiological stimulus, tactile stimulation, can be recorded along a nerve. These responses express the function of the whole distal part of the sensory pathway, including mechanoreceptors and their afferent fibers, structures by‐passed by the electrical stimulation. Using immunohistochemical procedures it is possible to investigate morphology and distribution of the neural structures presumably involved in the generation of tactile responses in digital glabrous skin. The mechanoreceptor density is higher in fingertip and in younger people. The area of the tactile potential tends to be smaller in older people and following the stimulation of the proximal phalanx with respect to the stimulation of the distal one, suggesting a correlation between tactile potential area and Meissner corpuscles' density. To assess the exact role of Meissner corpuscles in tactile potentials formation, we investigated in normal subjects the morphology, density and distribution of mechanoreceptors and their afferent myelinated fibers, and tactile and electrical responses. To correlate electrophysiological and morphological data we recruited a group of patients affected by congenital and acquired sensory neuropathies that underwent both skin biopsy and electrophysiological tests. We found a significant correlation between the area of the tactile potentials and the density of normal Meissner corpuscles and papillary myelinated fibers. These data support the hypothesis that Meissner corpuscles play a significant role in the generation of tactile potential. Therefore tactile stimulation is a reliable way to investigate the sensory pathway extreme termination.