Touch Receptors Undergo Rapid Remodeling in Healthy Skin.
Sensory tissues exposed to the environment, such as skin, olfactory epithelia, and taste buds, continuously renew; therefore, peripheral neurons must have mechanisms to maintain appropriate innervation patterns. Although somatosensory neurons regenerate after injury, little is known about how these neurons cope with normal target organ changes. To elucidate neuronal plasticity in healthy skin, we analyzed the structure of Merkel-cell afferents, which are gentle touch receptors, during skin remodeling that accompanies mouse hair-follicle regeneration. The number of Merkel cells is reduced by 90% and axonal arbors are simplified during active hair growth. These structures rebound within just days. Computational modeling predicts that Merkel-cell changes are probabilistic, but myelinated branch stability depends on Merkel-cell inputs. Electrophysiology and behavior demonstrate that tactile responsiveness is less reliable during active growth than in resting skin. These results reveal that somatosensory neurons display structural plasticity at the cost of impairment in the reliability of encoding gentle touch.
Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Integrated Training Program in Cellular, Molecular and Biomedical Sciences, Columbia University, New York, NY 10032, USA.
Kara L
KL
Marshall
Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Neurobiology and Behavior Training Program, Columbia University, New York, NY 10032, USA.
Rachel C
RC
Clary
Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
Yoshichika
Y
Baba
Department of Systems and Information Engineering, University of Virginia, Charlottesville, VA 22904, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904, USA.
Rachel L
RL
Orlowsky
Department of Systems and Information Engineering, University of Virginia, Charlottesville, VA 22904, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904, USA.
Gregory J
GJ
Gerling
Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Integrated Training Program in Cellular, Molecular and Biomedical Sciences, Columbia University, New York, NY 10032, USA; Neurobiology and Behavior Training Program, Columbia University, New York, NY 10032, USA; Department of Dermatology, Columbia University, New York, NY 10032, USA. Electronic address: eal2166@columbia.edu.
Ellen A
EA
Lumpkin
D000818:Animals; D001522:Behavior, Animal; D003198:Computer Simulation; D006197:Hair / Q000254:growth & development; D018862:Merkel Cells / Q000378:metabolism; D008810:Mice, Inbred C57BL; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012867:Skin / Q000378:metabolism*; D014110:Touch / Q000502:physiology*
D011956:Receptors, Cell Surface
Merkel cell; anagen; hair cycle; neuronal plasticity; skin; somatosensory; tactile; touch