title: Role of neuronal and inducible nitric oxide synthases in the guinea pig ileum myenteric plexus during in vitro ischemia and reperfusion.
abstract: BACKGROUND
  Intestinal ischemia and reperfusion (I/R) injury leads to abnormalities in motility, namely delay of transit, caused by damage to myenteric neurons. Alterations of the nitrergic transmission may occur in these conditions. This study investigated whether an in vitro I/R injury may affect nitric oxide (NO) production from the myenteric plexus of the guinea pig ileum and which NO synthase (NOS) isoform is involved.
  
  
  METHODS
  The distribution of the neuronal (n) and inducible (i) NOS was determined by immunohistochemistry during 60 min of glucose/oxygen deprivation (in vitro ischemia) followed by 60 min of reperfusion. The protein and mRNA levels of nNOS and iNOS were investigated by Western-immunoblotting and real time RT-PCR, respectively. NO levels were quantified as nitrite/nitrate.
  
  
  RESULTS
  After in vitro I/R the proportion of nNOS-expressing neurons and protein levels remained unchanged. nNOS mRNA levels increased 60 min after inducing ischemia and in the following 5 min of reperfusion. iNOS-immunoreactive neurons, protein and mRNA levels were up-regulated during the whole I/R period. A significant increase of nitrite/nitrate levels was observed in the first 5 min after inducing I/R and was significantly reduced by N(ω) -propyl-l-arginine and 1400 W, selective inhibitors of nNOS and iNOS, respectively.
  
  
  CONCLUSIONS
  Our data demonstrate that both iNOS and nNOS represent sources for NO overproduction in ileal myenteric plexus during I/R, although iNOS undergoes more consistent changes suggesting a more relevant role for this isoform in the alterations occurring in myenteric neurons following I/R.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Insubria, Varese, Italy. cristina.giaroni@uninsubria.it
authors.forename: C
authors.initials: C
authors.lastname: Giaroni
authors.forename: S
authors.initials: S
authors.lastname: Marchet
authors.forename: E
authors.initials: E
authors.lastname: Carpanese
authors.forename: V
authors.initials: V
authors.lastname: Prandoni
authors.forename: R
authors.initials: R
authors.lastname: Oldrini
authors.forename: B
authors.initials: B
authors.lastname: Bartolini
authors.forename: E
authors.initials: E
authors.lastname: Moro
authors.forename: D
authors.initials: D
authors.lastname: Vigetti
authors.forename: F
authors.initials: F
authors.lastname: Crema
authors.forename: S
authors.initials: S
authors.lastname: Lecchini
authors.forename: G
authors.initials: G
authors.lastname: Frigo
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006168:Guinea Pigs; D007082:Ileum / Q000201:enzymology*; D007150:Immunohistochemistry; D008297:Male; D009197:Myenteric Plexus / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000032:analysis / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000032:analysis / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D015427:Reperfusion Injury / Q000201:enzymology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II