title: Effects of ischemia and reperfusion on P2X2 receptor expressing neurons of the rat ileum enteric nervous system.
abstract: OBJECTIVE
  We investigated the effects of ischemia/reperfusion in the intestine (I/R-i) on purine receptor P2X2-immunoreactive (IR) neurons of the rat ileum.
  
  
  METHODS
  The superior mesenteric artery was occluded for 45 min with an atraumatic vascular clamp and animals were sacrificed 4 h later. Neurons of the myenteric and submucosal plexuses were evaluated for immunoreactivity against the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT), calbindin, and calretinin.
  
  
  RESULTS
  Following I/R-i, we observed a decrease in P2X2 receptor immunoreactivity in the cytoplasm and surface membranes of neurons of the myenteric and submucosal plexuses. These studies also revealed an absence of calbindin-positive neurons in the I/R-i group. In addition, the colocalization of the P2X2 receptor with NOS, ChAT, and calretinin immunoreactivity in the myenteric plexus was decreased following I/R-i. Likewise, the colocalization between P2X2 and calretinin in neurons of the submucosal plexus was also reduced. In the I/R-i group, there was a 55.8% decrease in the density of neurons immunoreactive (IR) for the P2X2 receptor, a 26.4% reduction in NOS-IR neuron, a 25% reduction in ChAT-IR neuron, and a 47% reduction in calretinin-IR neuron. The density of P2X2 receptor and calretinin-IR neurons also decreased in the submucosal plexus of the I/R-i group. In the myenteric plexus, P2X2-IR, NOS-IR, ChAT-IR and calretinin-IR neurons were reduced in size by 50%, 49.7%, 42%, and 33%, respectively, in the I/R-i group; in the submucosal plexus, P2X2-IR and calretinin-IR neurons were reduced in size by 56% and 72.6%, respectively.
  
  
  CONCLUSIONS
  These data demonstrate that ischemia/reperfusion of the intestine affects the expression of the P2X2 receptor in neurons of the myenteric and submucosal plexus, as well as density and size of neurons in this population. Our findings indicate that I/R-i induces changes in P2X2-IR enteric neurons that could result in alterations in intestinal motility.
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, CEP 05508-900, São Paulo, Brazil.
authors.forename: Ariane Silva
authors.initials: AS
authors.lastname: Paulino
authors.forename: Kelly
authors.initials: K
authors.lastname: Palombit
authors.forename: Gabriela
authors.initials: G
authors.lastname: Cavriani
authors.forename: Wothan
authors.initials: W
authors.lastname: Tavares-de-Lima
authors.forename: Márcia Sanae
authors.initials: MS
authors.lastname: Mizuno
authors.forename: Aline Rosa
authors.initials: AR
authors.lastname: Marosti
authors.forename: Marcos Vinícius
authors.initials: MV
authors.lastname: da Silva
authors.forename: Priscila Azevedo
authors.initials: PA
authors.lastname: Girotti
authors.forename: Edson Aparecido
authors.initials: EA
authors.lastname: Liberti
authors.forename: Patricia
authors.initials: P
authors.lastname: Castelucci
mesh_terms: D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D017615:Enteric Nervous System / Q000378:metabolism*; D005769:Gastrointestinal Motility; D007082:Ileum / Q000294:innervation* / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D017538:Mesenteric Artery, Superior / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D058476:Receptors, Purinergic P2X2 / Q000378:metabolism*; D015427:Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D064026:Calbindins; D058476:Receptors, Purinergic P2X2; D064030:S100 Calcium Binding Protein G; D052248:Nitric Oxide Synthase Type I; D002795:Choline O-Acetyltransferase