Essential Components for a Glutamatergic Synapse Between Merkel Cell and Nerve Terminal in Rats

The exact role of Merkel cells and their possible involvement in mechanosensation is unclear. The aim of this study was to determine, in the adult rat sinus hair follicle, the expression pattern of a number of vesicular proteins involved in neurotransmitter release to provide a clearer understanding of Merkel cell signalling mechanisms. We identified prominent expression and co-localization of the glutamatergic vesicle loading proteins VGLUT1 and VGLUT2 at the site of the sinus hair follicle known to be densely populated with Merkel cells. We also found expression of the vesicle recycling proteins synaptogyrin and syntaxin-6 in the same region of the hair follicle. Our data suggest that glutamate signalling is involved in Merkel cell mechanosensation and that vesicular trafficking is commonplace in the Merkel cell-neurite complex.