Elsevier

Neuroscience Letters

Volume 311, Issue 2, 28 September 2001, Pages 101-104
Neuroscience Letters

Functional role of inducible nitric oxide synthase on mouse colonic motility

https://doi.org/10.1016/S0304-3940(01)02156-5Get rights and content

Abstract

A possible functional role of inducible isoform of nitric oxide synthase (iNOS) was explored in vitro on the motility of mouse distal colon. Using an isotonic – non-isovolumic technique, peristaltic activity and video images of the external wall of colonic segments were recorded before and after addition to the medium of Aminoguanidine (AG) and N-(3-(aminomethyl)benzyl) acetamidine (W1400) [10−7 M–10−4 M], two iNOS inhibitors. AG and W1400 induced an hyperexcitability of visceral smooth muscle characterised by an increase of basal tone and spontaneous phasic activity. As a consequence of these effects, the peristaltic activity declined and disappeared at the highest concentrations. These findings indicated a removal of inhibitory action performed by NO synthesised by iNOS in the colonic segment. The implications of results are discussed in term of tonic relaxation of intestinal smooth muscle to allow intraluminal content accommodation.

Section snippets

Acknowledgements

The financial support of Telethon - Italy (Grant no. 1264 to G.B.A.) is gratefully acknowledged.

References (15)

There are more references available in the full text version of this article.

Cited by (16)

  • Neostigmine-induced contraction and nitric oxide-induced relaxation of isolated ileum from STZ diabetic guinea pigs

    2011, Autonomic Neuroscience: Basic and Clinical
    Citation Excerpt :

    Since prolonged suppression of nNOS by exogenous administration of 7-nitroindazole resulted in upregulation of intestinal iNOS mRNA, protein, and activity (Qu et al., 2001), one could speculate that diabetes-induced decrease in nNOS mRNA, protein, and enzyme activity (Martinez-Cuesta et al., 1995; Takahashi et al., 1997; Watkins et al., 2000; Cellek et al., 2003; Surendran and Kondapaka, 2005; Shotton and Lincoln, 2006; Zandecki et al., 2008) may result in upregulation of iNOS mRNA, protein, and activity. A physiologic role for iNOS in peristalsis of normal mouse colon has been proposed (Mancinelli et al., 2001); however, additional experiments using many NOS inhibitors with different selectivities for nNOS and iNOS are required to fully explore a physiologic role for iNOS in smooth muscle relaxation in diabetic animals. In general, ilea recovered better from l-arginine (3–30 mM) (Fig. 8A) than SNP (0.3–300 μM) (Fig. 8C) induced relaxations even though the magnitudes of smooth muscle relaxations were similar (Fig. 6).

View all citing articles on Scopus
View full text