title: The cellular and molecular basis of direction selectivity of Aδ-LTMRs.
abstract: The perception of touch, including the direction of stimulus movement across the skin, begins with activation of low-threshold mechanosensory neurons (LTMRs) that innervate the skin. Here, we show that murine Aδ-LTMRs are preferentially tuned to deflection of body hairs in the caudal-to-rostral direction. This tuning property is explained by the finding that Aδ-LTMR lanceolate endings around hair follicles are polarized; they are concentrated on the caudal (downward) side of each hair follicle. The neurotrophic factor BDNF is synthesized in epithelial cells on the caudal, but not rostral, side of hair follicles, in close proximity to Aδ-LTMR lanceolate endings, which express TrkB. Moreover, ablation of BDNF in hair follicle epithelial cells disrupts polarization of Aδ-LTMR lanceolate endings and results in randomization of Aδ-LTMR responses to hair deflection. Thus, BDNF-TrkB signaling directs polarization of Aδ-LTMR lanceolate endings, which underlies direction-selective responsiveness of Aδ-LTMRs to hair deflection.
authors.affiliation: Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rutlin
authors.affiliation: Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA; Department of Pathology, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Cheng-Ying
authors.initials: CY
authors.lastname: Ho
authors.affiliation: Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Abraira
authors.affiliation: Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Colleen
authors.initials: C
authors.lastname: Cassidy
authors.forename: Ling
authors.initials: L
authors.lastname: Bai
authors.affiliation: Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. Electronic address: woodbury@uwyo.edu.
authors.forename: C Jeffery
authors.initials: CJ
authors.lastname: Woodbury
authors.affiliation: Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA. Electronic address: david_ginty@hms.harvard.edu.
authors.forename: David D
authors.initials: DD
authors.lastname: Ginty
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D004622:Embryo, Mammalian; D004847:Epithelial Cells / Q000502:physiology; D005727:Ganglia, Spinal / Q000502:physiology*; D018859:Hair Follicle / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D008465:Mechanoreceptors / Q000145:classification / Q000502:physiology*; D051379:Mice; D020813:Receptor, trkB / Q000378:metabolism; D014110:Touch
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D020813:Receptor, trkB