Role of neuronal and inducible nitric oxide synthases in the guinea pig ileum myenteric plexus during in vitro ischemia and reperfusion
Article first published online: 2 JAN 2013
© 2012 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 25, Issue 2, pages e114–e126, February 2013
How to Cite
Giaroni, C., Marchet, S., Carpanese, E., Prandoni, V., Oldrini, R., Bartolini, B., Moro, E., Vigetti, D., Crema, F., Lecchini, S. and Frigo, G. (2013), Role of neuronal and inducible nitric oxide synthases in the guinea pig ileum myenteric plexus during in vitro ischemia and reperfusion. Neurogastroenterology & Motility, 25: e114–e126. doi: 10.1111/nmo.12061
- Issue published online: 22 JAN 2013
- Article first published online: 2 JAN 2013
- Received: 30 July 2012 Accepted for publication: 15 November 2012
- guinea pig ileum;
- in vitro ischemia/reperfusion;
- myenteric plexus;
- nitric oxide;
- nitric oxide synthase
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.
Key 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 Nω-propyl-l-arginine and 1400 W, selective inhibitors of nNOS and iNOS, respectively.
Conclusions & Inferences 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.