title: Early expression of adenosine 5'-triphosphate-gated P2X7 receptors in the developing rat pancreas.
abstract: OBJECTIVE
  Extracellular adenosine 5'-triphosphate modulates the functions of the adult pancreas via 2 nucleotide receptor families, the P2X and P2Y receptors. Expression of the P2X7 receptor has been demonstrated in islet cells of the pancreas, particularly the mature alpha cells that secrete glucagon. In the streptozotocin-induced diabetic model, a loss of insulin-secreting cells was accompanied by an increase in alpha cells that expressed the P2X7 receptor.
  
  
  METHODS
  In the present study, we have examined the expression of P2X7 receptors in the developing pancreas from embryonic days 10 (E10) to E18.
  
  
  RESULTS
  We detected P2X7 receptor-immunoreactive cells in pancreatic islet cells as early as E11' before glucagon expression. Subsequently, P2X7 receptors were expressed in glucagon-secreting cells at E12, and complete colocalization was observed at E14. Occasional colocalization of P2X7 receptors and insulin was observed in scattered cells at E12 and E14, but not at E18, when the glucagon- and insulin-secreting cells were almost completely segregated.
  
  
  CONCLUSIONS
  It was found that P2X7 receptors were expressed early in a subpopulation of glucagon- and insulin-immunopositive cells in developing islets and subsequently became restricted to glucagon-expressing cells as development proceeded. The possible functional significance of these changes is discussed.
authors.affiliation: Autonomic Neuroscience Centre, Royal Free and University College Medical School, London, United Kingdom.
authors.forename: Kwok Kuen
authors.initials: KK
authors.lastname: Cheung
authors.forename: Robson
authors.initials: R
authors.lastname: Coutinho-Silva
authors.forename: Wood Yee
authors.initials: WY
authors.lastname: Chan
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Burnstock
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D005934:Glucagon / Q000378:metabolism; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis; D015640:Ion Channel Gating; D007515:Islets of Langerhans / Q000196:embryology; D010179:Pancreas / Q000196:embryology* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000502:physiology*; D058486:Receptors, Purinergic P2X7
chemical_list: D007328:Insulin; C546470:P2rx7 protein, rat; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D005934:Glucagon