Figure 7.

Immunohistochemical profile of human cutaneous Pacinian corpuscles. Immunohistochemical localization of neurofilament proteins (NFP), S100 protein (S100P), acid-sensing ion channel 2 (ASIC2), PIEZO2, CD34 and vimentin in human digital Pacinian corpuscles. Pacinian corpuscles are divided into two main compartments: the neural compartment (NC), which comprises the axon and the glial cells, and the non-neural compartment (n-NC), which comprises both the outer core and the capsule of perineurial origin. Both compartments are separated by an intermediate layer of endoneurial origin. All the Pacinian corpuscle constituents can be selectively immunolabeled. (a) The axon displaying immunoreactivity for NFP; (b) the inner core lamellae are S100P immunoreactive; (c,d) occurrence of the mechanoproteins ASIC2 and PIEZO2, respectively, in the axon; a faint immunoreactivity for ASIC2 is also present in the inner core; (e–g) double immunofluorescence, demonstrating that lamellar cells forming the inner core display the S100P and are covered by a layer of endoneurial-related cells (CD34-positive), the so-called intermediate layer; (h–j) double immunofluorescence, demonstrating that the lamellar system of Pacinian corpuscles (inner core, intermediate later, outer core, capsule) display vimentin and the division of Pacinian corpuscles into NC (within the CD34+ intermediate layer) and n-NC. Ax: axon; c: capsule; ic: inner core; il: intermediate layer; oc: outer core.