Merkel Cell Receptors: Structure and Transducer Function

Abstract

An electron microscopic and electrophysiological investigation was made of Merkel cell-neurite complexes in the sinus hair follicles of the cat. These mechanoreceptors respond with very precise phase locking to heavy-frequency vibratory stimuli as well as to static hair displacements. The mechanoelectric transduction process is faster than that known for any other somatic mechanoreceptor. These data show that the nerve endings themselves and not the Merkel cells are the mechanoelectric transducer elements in these receptors.

Molecular profiling reveals synaptic release machinery in Merkel cells

“…Consistent with this notion, Merkel cells contain dense-core vesicles that resemble neurosecretory vesicles (10). Moreover, Merkel cell-neurite complexes have membrane densities like those at synaptic active zones (11); however, some have argued that these are merely sites of adhesion (12).…”

“…For example, removing Merkel cells by enzymatic treatment, photoablation, or genetic modification abolished the responses of slowly adapting afferents in some studies (14,15), but not in others (16). Reports of the involvement of synaptic transmission in slowly adapting type I responses are likewise contradictory (12,17). Recent evidence for excitatory neurotransmission is the finding that an inhibitor of ionotropic glutamate receptors reduces slowly adapting type I responsiveness (18).…”

“…For example, Merkel cells may play a passive role in touch by efficiently transmitting force to mechanosensitive afferents (12). Alternatively, they may release neuromodulators to regulate the sensitivity of mechanoreceptive neurons (20 Fluorescence-Activated Cell Sorting (FACS).…”

Empirically inspired simulated electro-mechanical model of the rat mystacial follicle-sinus complex

“…The classical study of their response involves headfixing the animal, performing a controlled whisker deflection, and observing the characteristics of the evoked response train ( passive deflection study) (Zucker & Welker 1969;Hahn 1971;Gottschaldt et al 1973;Dykes 1975;Gottschaldt & Vahle-Hinz 1981;Gibson & Welker 1983a,b;Lichtenstein et al 1990;Shoykhet et al 2000). Baumann et al (1996) applied a similar deflect and record technique to a whisker-FSC assembly isolated and fixed in vitro.…”

Fine structure of Eimer's organ in the coast mole (Scapanus orarius)

“…7B and C). Given this, it is reasonable to suggest that they provide a slowly adapting SA-1 signaling component to the Eimer's organ receptor complex (Iggo and Muir, 1969;Gottschaldt and Vahle-Hinz, 1981). The circular arrangement of these receptors around the base of the central column, in conjunction with the presumably more rigid cells of the central column, may also provide these receptors with the ability to code for directional input as provided by differential pressure transmitted through the central column (Quilliam, 1966).…”