The Merkel rete papilla — a slowly adapting sensory receptor in mammalian glabrous skin

doi:10.1016/0006-8993(71)90416-1

Brain Research

Volume 29, Issue 1, 4 June 1971, Pages 47-61

https://doi.org/10.1016/0006-8993(71)90416-1 Get rights and content

Abstract

The present study has identified the anatomical receptor characterized physiologically as a slowly adapting mechanoreceptor. The receptor has been named a Merkel rete papilla (M-r papilla). An M-r papilla consists of a group of Merkel cells, associated neurites and epidermal cells projecting from the lower portion of a rete ridge into the dermis. Three to six individual nerve fibers enter a papilla and repeatedly divide. Fine terminal branches become associated with Merkel cells in a manner similar to other Merkel cell-neurite complexes described previously. The Merkel cell-neurite complexes in the M-r papillae are the anatomical substrate for the slowly adapting receptors present in raccoon glabrous palmar skin.

Reference (31)

BarkerD.J. et al.
Receptive fields of first-order somatic sensory neurons innervating rhinarium in coati and raccoon
Brain Research
(1969)
SmithK.R.
The ultrastructure of the humanHaarscheibe and Merkel cell
J. Invest. Dermatol.
(1970)
SmithK.R. et al.
Effects of pharmacological agents on the physiological responses of hair discs
Exp. Neurol.
(1967)
TapperD.A.
Stimulus-response relationships in the cutaneous slowly adapting mechanoreceptor in hairy skin of the cat
Exp. Neurol.
(1965)
ZuckerE. et al.
Coding of somatic sensory input by vibrissae neurons in the rat's trigeminal ganglion
Brain Research
(1969)
AndresK.H.
U¨ber die Feinstruktur der Rezeptoren an Sinushaaren
Z. Zellforsch.
(1966)
BoekeJ.
Nerve endings, motor and sensory
CajalS. et al.
Accion neurotropica de los epitelios
Trab. Inst. Cajal de Invest. Biol.
(1919)
FitzgeraldO.
Discharges from the sensory organs of the cat's vibrissae and the modification in their activity by ions
J. Physiol. (Lond.)
(1940)
HogganG.
New forms of nerve terminations in mammalian skin
J. Anat. Physiol.
(1884)

IggoA. et al.

The structure and function of a slowly adapting touch corpuscle in hairy skin

J. Physiol. (Lond.)

(1969)

Ja¨nigW. et al.

Single unit responses and the total afferent outflow from the cat's foot pad upon mechanical stimulation

Exp. Brain Res.

(1968)

KarnovskyM.J.

A formaldehyde-glutaraldehyde fixative high osmolarity for use in electron microscopy

J. Cell Biol.

(1965)

KarnovskyM.J.

Ultrastructural bases of capillary permeability studied with peroxidase as a tracer

J. Cell Biol.

(1967)

LindbloomU.

Properties of touch receptors in distal glabrous skin of the monkey

J. Neurophysiol.

(1965)

Cited by (67)

The sensory neurons of touch
2013, Neuron
Citation Excerpt :
Merkel (1875) was the first to histologically describe an epidermal cell cluster forming contacts with afferent nerve fibers in vertebrate skin. A century later, the Merkel cell-neurite complex was described as the cellular substrate of SAI-LTMRs by meticulous histological analysis of SAI receptive fields mapped onto the skin (Halata et al., 2003; Iggo and Muir, 1969; Munger et al., 1971; Woodbury and Koerber, 2007) (Figure 1). Merkel cell clusters are distributed throughout the skin, with each individual Merkel cell found in close apposition to one enlarged Aβ SAI-LTMR terminal.
The somatosensory system decodes a wide range of tactile stimuli and thus endows us with a remarkable capacity for object recognition, texture discrimination, sensory-motor feedback and social exchange. The first step leading to perception of innocuous touch is activation of cutaneous sensory neurons called low-threshold mechanoreceptors (LTMRs). Here, we review the properties and functions of LTMRs, emphasizing the unique tuning properties of LTMR subtypes and the organizational logic of their peripheral and central axonal projections. We discuss the spinal cord neurophysiological representation of complex mechanical forces acting upon the skin and current views of how tactile information is processed and conveyed from the spinal cord to the brain. An integrative model in which ensembles of impulses arising from physiologically distinct LTMRs are integrated and processed in somatotopically aligned mechanosensory columns of the spinal cord dorsal horn underlies the nervous system’s enormous capacity for perceiving the richness of the tactile world.
Evaluation of hand sensibility: A review
2001, Journal of Hand Therapy
Many assessment devices and measures have been described to evaluate ensibility, with little consensus on the optimal measurement tool. The urpose of this paper is to review the assessment methods and devices used in he evaluation of hand sensibility. Consideration is given to the haracteristics of each measurement tool, the information necessary for omplete patient evaluation, and the battery of valid and reliable easurements that provide the most complete and accurate patient assessment.
The force/time relationship of clinically used sensory testing instruments
1997, Journal of Hand Therapy
The stimuli of commonly used sensibility measurement instruments tested in this study demonstrate unequivocally that “hand-held instruments” produce variations in application force from one stimulation to another, one instrument to another, and from one examiner to another. These application force variations cannot be compensated for by care in technique and need to be controlled for measurement reliability. Only the Semmes-Weinstein monofilaments provide some control of force during application and can be considered force controlled if calibrated and applied correctly. The monofilaments, too, become less controllable if applied too quickly and bounced against the skin. Two-point discrimination instruments, in particular, lack control of application force, with the force of one point significantly different from two points. A difference in applied force makes it possible for a patient to solve the two-point discrimination test by discerning the difference between heavier and lighter forces, rather than one or two-point recognition. Tuning fork instruments for vibration testing have even larger variations in application force amplitude rendering their stimulus highly uncontrolled and masking the actual vibration of the tuning fork. Spectral analysis of the force frequency signal produced by hand held sensibility measurement instruments shows they all produce both high and low frequency signals sufficient in strength to stimulate both slowly adapting and quickly adapting end organs, and are not capable of stimulating one particular group. These dynamic properties of testing stimuli explain why our tests are not as repeatable and sensitive as desired. The understanding of these dynamic properties in sensibility measurement is a key for improved instruments and more repeatable findings in clinical testing.
Special program of differentiation expressed in keratinocytes of human haarscheiben: an analysis of individual cytokeratin polypeptides
1993, Journal of Investigative Dermatology
Human haarscheiben, epidermal Merkel cell-rich sensory organs of hairy skin, were studied for the expression of various cytokeratin (CK) polypeptides and other epithelial and neuronal differentiation markers by applying immunoperoxidase and immunofluorescence microscopy to frozen sections and by two-dimensional gel electrophoresis. The basal clusters of Merkel cells were specifically detected by antibodies against CK 20. Haarscheiben keratinocytes were unique mainly by the prominent expression of CK 17 in the lower and middle layers. Further differences as compared to keratinocytes of usual epidermis included the enlargement of the basal compartment, characterized by the expression of CK 5 and the absence of the maturation-associated CKs 1/10/11, and the reduction of CK 15, which is a constituent of normal basal cells. Using CK 17 as a highly sensitive Haarscheibe marker in skin tissue sections, variabilities in the spatial relationship of the haarscheibe and the corresponding hair follicle were recorded. The results show that haarscheibe keratinocytes express a special program of differentiation that may be important for optimal stimulus perception. Immunohistochemical stainings for CK 17 will facilitate further studies on the distribution and biology of haarscheibe.
Coding of stimulus location and intensity in populations of mechanosensitive nerve fibers of the raccoon: I. Single fiber response properties
1990, Brain Research Bulletin
The primary aim of this study was to determine and compare the receptive field (RF) characteristics and response properties of single mechanosensitive nerve fibers innervating the glabrous skin of the forepaw and hindpaw of the raccoon. The action potentials of 129 median nerve fibers and 61 posterior tibial nerve fibers were recorded in response to punctate mechanical stimuli varying in location and intensity. The stimuli were delivered to six standard test sites on digit 1 and the contiguous pads of each paw. Attempts were made to classify each fiber according to its rate of adaptation to sustained stimulation; the RF of each fiber was mapped using a standard series of stimulus intensities. The results indicated that the response properties of individual fibers were highly complex and depended on the location and intensity of stimulation. 1) The distributions of absolute threshold were not different for the median or tibial nerve fibers or for different classes of fibers based on adaptation rate. A distal to proximal increase in threshold was found for each paw, suggesting a corresponding gradient of sensitivity across the glabrous skin. 2) Threshold RF areas did not vary across either paw nor did they differ between the two paws. Suprathreshold RFs were quite large relative to expected tactile acuity and displayed complex features. 3) Response properties such as adaptation rate, on- and off-responses, were found to vary with both stimulus location and intensity. It was concluded that the responses of individual nerve fibers could not uniquely encode any stimulus parameter tested, and that the properties of single fibers could not account for apparent differences in tactile acuity across each paw or between the two paws.
The force/time relationship of clinically used sensory testing instruments
1988, Journal of Hand Therapy
The stimuli tested in this study demonstrate that hand-held instrument tests produce variations in force of application from one application to another and from one examiner to another, which cannot be compensated for by care in application. Only the Semmes-Weinstein monofilaments provide control during force of application. The monofilaments, too, become less controllable if applied too quickly. Two-point discrimination instruments, in particular, are uncontrollable during application force, with the force of one point significantly different from two points, making it possible for a patient to solve the test by the difference between heavier and lighter forces. Analysis of the frequency signal produced by currently used sensibility testing instruments by a spectrum analyzer shows that they produce high and low frequency signals that cannot stimulate only slowly adapting or quickly adapting end organs. These dynamic properties of testing stimuli explain why our tests are not as repeatable and sensitive as desired. Their understanding holds the key for improved instruments and more repeatable findings in clinical testing.

View all citing articles on Scopus

View full text

The Merkel rete papilla — a slowly adapting sensory receptor in mammalian glabrous skin

Abstract

Brain Research

J. Invest. Dermatol.

Exp. Neurol.

Exp. Neurol.

Brain Research

U¨ber die Feinstruktur der Rezeptoren an Sinushaaren

Z. Zellforsch.

Nerve endings, motor and sensory

Accion neurotropica de los epitelios

Trab. Inst. Cajal de Invest. Biol.

Discharges from the sensory organs of the cat's vibrissae and the modification in their activity by ions

J. Physiol. (Lond.)

New forms of nerve terminations in mammalian skin

J. Anat. Physiol.

The structure and function of a slowly adapting touch corpuscle in hairy skin

J. Physiol. (Lond.)

Single unit responses and the total afferent outflow from the cat's foot pad upon mechanical stimulation

Exp. Brain Res.

A formaldehyde-glutaraldehyde fixative high osmolarity for use in electron microscopy

J. Cell Biol.

Ultrastructural bases of capillary permeability studied with peroxidase as a tracer

J. Cell Biol.

Properties of touch receptors in distal glabrous skin of the monkey

J. Neurophysiol.