Authors
  Navarro X.  Verdu E.  Wendelschafer-Crabb G.  Kennedy WR.
Title
  Immunohistochemical study of skin reinnervation by regenerative axons.
Source
  Journal of Comparative Neurology.  380(2):164-74, 1997 Apr 7.
Abstract
  The time sequence of sensory and sudomotor nerve regeneration to the mouse
  footpad was studied between one and seven weeks after crush or section of
  the sciatic nerve. Protein gene product 9.5, vasoactive intestinal
  peptide, substance P, and calcitonin gene-related peptide were localized
  in thick sections by using indirect immunofluorescence techniques and
  imaged by confocal microscopy. Nerve regeneration was visually assessed in
  all nerves and quantified in sweat glands. After denervation, protein gene
  product 9.5 immunoreactivity remained as dim fluorescence within thick
  fibers of dermal nerve trunks, whereas thin nerve fibers to sweat glands
  and to epidermis disappeared. By 14 days postcrush and 35 days
  postsection, the first protein gene product 9.5 immunoreactive
  regenerating axons appeared in large nerve trunks, quickly extending to
  epidermis and sweat glands. Reinnervation of Meissner's corpuscles
  occurred nearly simultaneous with return of epidermal free nerve endings
  and sudomotor network. Calcitonin gene-related peptide, vasoactive
  intestinal peptide, and substance P immunoreactivity disappeared
  completely one week after denervation, then reappeared at 17-18 days
  postcrush and 35 days postsection. Fewer nerve fibers were immunoreactive
  to these peptides than to protein gene product 9.5. The overall density of
  reinnervation, although reduced, more closely resembled normal in the
  sweat glands and Meissner's corpuscles than in the epidermis.
  Reinnervation was more successful after crush than after nerve section.
  The time course for functional return of sweating paralleled the return of
  protein gene product 9.5 immunoreactivity, whereas appearance of
  vasoactive intestinal peptide was delayed by several days.