Polyethylene glycol-induced contraction of vascular smooth muscle in the ileum of the rat is mediated by a cholinergic mechanism.
Polyethylene glycol (PEG) is a water-soluble polymer used in the manufacture of several semisynthetic drugs and is commonly present in the pharmaceutical preparations. Previous studies have shown that PEG can induce contraction in the colonic smooth muscle, but the contractile effect of PEG in other parts of the gastrointestinal tract is not known. In the present study, the effect of PEG on contractile response of the rat ileum smooth muscle was examined. PEG solutions at 25 and 50 mg/ml induced contraction of the longitudinal muscle strips. Contractile responses were dose-dependent and were significantly reduced in the presence of the cholinergic antagonist atropine (1 x 10(-6) M) but not the beta-adrenoceptor antagonist propranolol (1 x 10(-5) M). The contractile responses induced by PEG in the ileum were unaffected by tetrodotoxin, indomethacin, tetraethylammonium and diethyldithiocarbamate (DDC), indicating that PEG does not act by stimulation of sensory nerves or inhibition of prostanoid synthesis. However, these contractile responses were significantly inhibited by PEG in the presence of acetylcholine (Ach) (3 x 10(-7) M) and ACh + atropine (1 x 10(-6) M). These findings indicate that PEG is capable of inducing contraction of the ileal smooth muscle and suggest that the effect is mediated by stimulation of cholinergic nerves.// Boost.Units - A C++ library for zero-overhead dimensional analysis and
// unit/quantity manipulation and conversion
//
// Copyright (C) 2003-2008 Matthias Christian Schabel
// Copyright (C) 2008 Steven Watanabe
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
//
#ifndef BOOST_UNITS_SI_POTENTIAL_DENSITY_HPP
#define BOOST_UNITS_SI_POTENTIAL
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