title: Glutamatergic modulation of synaptic-like vesicle recycling in mechanosensory lanceolate nerve terminals of mammalian hair follicles.
abstract: Our aim in the present study was to determine whether a glutamatergic modulatory system involving synaptic-like vesicles (SLVs) is present in the lanceolate ending of the mouse and rat hair follicle and, if so, to assess its similarity to that of the rat muscle spindle annulospiral ending we have described previously. Both types of endings are formed by the peripheral sensory terminals of primary mechanosensory dorsal root ganglion cells, so the presence of such a system in the lanceolate ending would provide support for our hypothesis that it is a general property of fundamental importance to the regulation of the responsiveness of the broad class of primary mechanosensory endings. We show not only that an SLV-based system is present in lanceolate endings, but also that there are clear parallels between its operation in the two types of mechanosensory endings. In particular, we demonstrate that, as in the muscle spindle: (i) FM1-43 labels the sensory terminals of the lanceolate ending, rather than the closely associated accessory (glial) cells; (ii) the dye enters and leaves the terminals primarily by SLV recycling; (iii) the dye does not block the electrical response to mechanical stimulation, in contrast to its effect on the hair cell and dorsal root ganglion cells in culture; (iv) SLV recycling is Ca(2+) sensitive; and (v) the sensory terminals are enriched in glutamate. Thus, in the lanceolate sensory ending SLV recycling is itself regulated, at least in part, by glutamate acting through a phospholipase D-coupled metabotropic glutamate receptor.
authors: University of Aberdeen, School of Medical Sciences, School of Medical Sciences, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK. g.s.bewick@abdn.ac.uk
authors: Robert W
authors: RW
authors: Banks
authors: Peter M B
authors: PM
authors: Cahusac
authors: Anna
authors: A
authors: Graca
authors: Nakul
authors: N
authors: Kain
authors: Fiona
authors: F
authors: Shenton
authors: Paramjeet
authors: P
authors: Singh
authors: Arild
authors: A
authors: Njå
authors: Anna
authors: A
authors: Simon
authors: Sonia
authors: S
authors: Watson
authors: Clarke R
authors: CR
authors: Slater
authors: Guy S
authors: GS
authors: Bewick
mesh_terms: D000818:Animals; D054644:Ear Auricle; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D018698:Glutamic Acid / Q000502:physiology*; D018859:Hair Follicle / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009411:Nerve Endings / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D051381:Rats; D013572:Synaptic Vesicles / Q000502:physiology*
chemical_list: C073804:FM1 43; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D018698:Glutamic Acid