title: Intrapancreatic axonal hyperbranching of dorsal root ganglia neurons in chronic pancreatitis model rats and its relation to pancreatic pain.
abstract: OBJECTIVE
  Increase in number of intrapancreatic nerve bundles has been implicated in the generation of persistent pain in chronic pancreatitis. To examine the origin of these nerve fibers and the mechanisms linking neural morphological change to pain generation, we used neuronal tracing techniques in combination with immunohistochemistry in spontaneous chronic pancreatitis in the Wistar Bonn/Kobori (WBN/Kob) rats.
  
  
  METHODS
  For retrograde tracing, horseradish peroxidase was injected into the pancreas, and labeled neurons in the sensory ganglia were counted. For anterograde tracing, biotinylated dextran amine was injected into the dorsal root ganglia (DRGs), and labeled intrapancreatic sensory fibers were histochemically assessed. For assessment of pain generation, we evaluated c-Fos-positive neurons in the spinal dorsal horn and behavioral changes of the animals.
  
  
  RESULTS
  In WBN/Kob rats, the numbers of horseradish peroxidase-labeled neurons were decreased in the DRGs, and the numbers of biotinylated dextran amine-labeled intrapancreatic nerve fibers and terminals were increased. Biotinylated dextran amine-labeled nerve fibers contained growth-associated protein 43. The number of c-Fos-positive neurons in the dorsal horn was also increased and was correlated with intrapancreatic growth-associated protein 43 immunoreactivity. Grooming behavior was reduced in WBN/Kob rats, and this reduction was facilitated by exocrine stimulation.
  
  
  CONCLUSIONS
  Axonal branching in DRG neurons innervating the pancreas increases in WBN/Kob rats, and these morphological changes are likely involved in pain generation in chronic pancreatitis.
authors.affiliation: Department of Anatomy and Cell Science, Kansai Medical University, Osaka, Japan.
authors.forename: Shoichiroh
authors.initials: S
authors.lastname: Takamido
authors.forename: Yosky
authors.initials: Y
authors.lastname: Kataoka
authors.forename: Akihide
authors.initials: A
authors.lastname: Tanano
authors.forename: Yilong
authors.initials: Y
authors.lastname: Cui
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ikeura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shimatani
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Kubota
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Okazaki
authors.forename: Hisao
authors.initials: H
authors.lastname: Yamada
mesh_terms: D000818:Animals; D001370:Axonal Transport; D002908:Chronic Disease; D004195:Disease Models, Animal; D005727:Ganglia, Spinal / Q000473:pathology* / Q000502:physiology; D009474:Neurons / Q000473:pathology* / Q000502:physiology; D010179:Pancreas / Q000294:innervation* / Q000473:pathology*; D010195:Pancreatitis / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar