Decreased ileal muscle contractility and increased nitric oxide
synthase ii expression induced by lipopolysaccharide.
Weisbrodt, Norman W., Thomas A. Pressley, Yong-Fang Li, Malgorzata J.
Zembowicz, Sandra C. Higham, Artur Zembowicz, Robert F. Lodato, and
Frank G. Moody.
Department of Integrative Biology, Department of Surgery and The
Trauma Research Center, University of Texas Medical School, Houston,
Texas 77030
APStracts 3:0040G, 1996.
This study was designed to determine if an increase in nitric oxide
synthase (NOS) activity induced by lipopolysaccharide (LPS) is
associated with increases in NOS II protein and mRNA abundance, and
with altered ileal longitudinal muscle contractility. Strips of
muscle taken from LPS-treated, but not control, animals exhibited
reduced in vitro contractility when L-arginine was a component of the
physiological salt solution. This reduction was reversed by N -nitro
-L-arginine (L-NNA), a competitive inhibitor of NOS. Full-thickness
segments of jejunum, ileum, and colon taken 5 h after LPS injection
exhibited increased NOS activity, NOS II immunoreactivity, and NOS II
mRNA abundance. Increased NOS II immunoreactivity and mRNA abundance
also were detected in ileal muscle strips taken from LPS-treated
animals. These data confirm the reported effects of LPS on intestinal
NOS activity and indicate that it can be attributed, at least in
part, to an increase in NOS II mRNA and protein abundance.
Furthermore, the data suggest that an LPS-induced increase in NOS II
may lead to a decrease in ileal muscle contractility.
Received 28 August 1995; accepted in final form 27 January 1996.
APS Manuscript Number G376-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 14 February 96