Merkel cell were first identified by German anatomist Friedrich Sigmund Merkel in 1875. Merkel cells are epidermal cells localised in the basal layer of the epidermis and the epithelial sheath of hair follicles. The vast majority of Merkel cells are intimately associated with a nerve terminal but some are not.
Whether Merkel cells originate from embryonic epidermal or neural crest progenitors has been a matter of intense controversy but recent data demonstrate an epidermal origin of mammalian Merkel cells.
Merkel cells are sensory receptor cells, that transmit signals through synaptic contacts with somatosensory neurons. Merkel cell-neurite complex are among the most sensitive touch receptors mediating one form of light touch important for tactile two-point discrimination and for detection of shapes, curvature and textures.
The Merkel cells that are without contact to nerve terminals form part of the diffuse neuroendocrine system involved with modulation of peripheral neural responses. It is these cells, rather than those acting as mechanoreceptors, that are believed to be at the origin of a highly malignant skin cancer called Merkel cell carcinoma.