Search results for " Smooth"
showing 10 items of 455 documents
Nitric oxide induces muscular relaxation via cyclic GMP-dependent and -independent mechanisms in the longitudinal muscle of the mouse duodenum
2003
The aim of this study was to investigate, in mouse duodenum, the role of nitric oxide (NO) in the relaxation of longitudinal muscle evoked by nerve activation and the coupled action mechanism. Electrical field stimulation (EFS; 0.5ms, 10-s train duration, supramaximal voltage, at various frequencies) under nonadrenergic noncholinergic conditions evoked muscular relaxation occasionally followed, at the higher stimulus frequencies, by rebound contractions. Inhibition of the synthesis of NO by Nω-nitro-L-arginine methyl ester (L-NAME; 100μM) virtually abolished the evoked relaxation. The relaxation was reduced also by apamin (0.1μM) and by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1μM)…
Spontaneous mechanical activity and evoked responses in isolated gastric preparations from normal and dystrophic (mdx) mice
2002
This study examined whether alterations of the spontaneous and evoked mechanical activity are present in the stomach of the mdx mouse, the animal model for Duchenne muscular dystrophy. The gastric mechanical activity from whole-organ of normal and mdx mice was recorded in vitro as changes of intraluminal pressure. All gastric preparations developed spontaneous tone and phasic contractions, although the tone of the mdx preparations was significantly greater. Atropine reduced the tone of the two preparations by the same degree. Nomega-nitro-l-arginine methyl ester (l-NAME) significantly increased the tone and spontaneous contractions only in the stomach from normal animals, but did not affect…
Mechanisms underlying the nitric oxide inhibitory effects in mouse ileal longitudinal muscle
2005
We investigated the mechanisms involved in the nitric oxide (NO)-induced inhibitory effects on longitudinal smooth muscle of mouse ileum, using organ bath technique. Exogenously applied NO, delivered as sodium nitroprusside (SNP; 0.1–100 µmol/L) induced a concentration-dependent reduction of the ileal spontaneous contractions. 1H-[1,2,4]oxadiazolol[4,3,a]quinoxalin-1-one (ODQ; 1 µmol/L), a guanilyl cyclase inhibitor, reduced the SNP-induced effects. Tetraethylammonium chloride (20 mmol/L), a non-selective K+ channel blocker, and charybdotoxin (0.1 µmol/L), blocker of large conductance Ca2+-dependent K+ channels, significantly reduced SNP-induced inhibitory effects. In contrast, apamin (0.1…
Nitrergic and purinergic interplay in inhibitory transmission in rat gastric fundus.
2007
Summary 1 This study was undertaken to analyse the involvement of ATP in non-adrenergic non- cholinergic (NANC) relaxation and possible interplay between nitrergic and purinergic systems in rat gastric fundus. 2 Experiments were performed in vitro on strips of longitudinal muscle from rat gastric fundus, recording the mechanical activity as changes in isometric force. In addition, NO release induced by different experimental conditions was assayed. 3 Under NANC conditions in serotonin-precontracted strips, electrical field stimulation (EFS) elicited a tetrodotoxin (TTX)-sensitive relaxation accompanied by nitric oxide (NO) release. This effect was antagonized by pretreatment with the NO …
Nitric oxide is involved in non-adrenergic, non-cholinergic inhibitory neurotransmission in rat duodenum
1995
1. In rat duodenum, electrical field stimulation (EFS) induced a relaxation due to activation of non-adrenergic, non-cholinergic (NANC) inhibitory intramural neurones. 2. Nitric oxide synthase (NOS) inhibitors, N omega-nitro-L-arginine (L-NNA) and N omega-nitro-L-arginine methyl ester (L-NAME), caused a dose-dependent reduction in amplitude of the NANC relaxation. Responses to low frequencies of stimulation were more sensitive to NOS inhibitors than those to high frequencies. 3. Effects induced by NOS inhibitors were stereospecific since D-NNA and D-NAME did not affect NANC relaxation. L-arginine, but not D-arginine, partially prevented the effects induced by NOS inhibitors on NANC relaxati…
Identification of the Muscarinic Acetylcholine Receptor Subtype Mediating Cholinergic Vasodilation in Murine Retinal Arterioles
2011
To identify the muscarinic acetylcholine receptor subtype that mediates cholinergic vasodilation in murine retinal arterioles.Muscarinic receptor gene expression was determined in murine retinal arterioles using real-time PCR. To assess the functional relevance of muscarinic receptors for mediating vascular responses, retinal vascular preparations from muscarinic receptor-deficient mice were studied in vitro. Changes in luminal arteriole diameter in response to muscarinic and nonmuscarinic vasoactive substances were measured by video microscopy.Only mRNA for the M(3) receptor was detected in retinal arterioles. Thus, M(3) receptor-deficient mice (M3R(-/-)) and respective wild-type controls …
Ceramide inhibits Kv currents and contributes to TP-receptor-induced vasoconstriction in rat and human pulmonary arteries
2011
et al.
Cigarette smoke exposure up-regulates endothelin receptor B in human pulmonary artery endothelial cells: molecular and functional consequences
2010
BACKGROUND AND PURPOSEPulmonary arteries from smokers and chronic obstructive pulmonary disease patients show abnormal endothelium-dependent vascular reactivity. We studied the effect of cigarette smoke extract (CSE) on endothelin receptor B (ETB) expression in human pulmonary artery endothelial cells (HPAECs) and its role in endothelial dysfunction.EXPERIMENTAL APPROACHETB receptor expression was measured by real time RT-PCR, Western blot and immunofluorescence. Cell contraction, intracellular Ca2+, F/G-actin, RhoA activity, myosin light chain phosphorylation, ET, NO, thromboxane (Tx)A2 and reactive oxygen species (ROS) were measured by traction microscopy, fluorescence microscopy, phalloi…
Vascular effects of sildenafil in patients with pulmonary fibrosis and pulmonary hypertension: an ex vivo/in vitro study
2015
Sildenafil improves the 6-min walking distance in patients with idiopathic pulmonary fibrosis (IPF) and right-sided ventricular systolic dysfunction.We analysed the previously unexplored role of sildenafil on vasoconstriction and remodelling of pulmonary arteries from patients with IPF and pulmonary hypertension (PH) ex vivo. Pulmonary arteries from 18 donors without lung disease, nine IPF, eight PH+IPF and four PH patients were isolated to measure vasodilator and anti-contractile effects of sildenafil in isometric organ bath. Ventilation/perfusion was explored in an animal model of bleomycin lung fibrosis.Sildenafil relaxed serotonin (5-HT) pre-contracted pulmonary arteries in healthy dono…
Activation of P2Y receptors by ATP and by its analogue, ADPbetaS, triggers two calcium signal pathways in the longitudinal muscle of mouse distal col…
2008
Our previous research showed that ATP and adenosine 5'-O-2-thiodiphosphate (ADPbetaS) induce contractile effects in the longitudinal muscle of mouse distal colon via activation of P2Y receptors which are not P2Y(1) or P2Y(12) subtypes. This study investigated the nature of the P2Y receptor subtype(s) and the mechanisms leading to the intracellular calcium concentration increase necessary to trigger muscular contraction. Motor responses of mouse colonic longitudinal muscle to P2Y receptor agonists were examined in vitro as changes in isometric tension. ATP or ADPbetaS induced muscular contraction, which was not affected by P2Y(11) or P2Y(13) selective antagonists. Calcium-free solution or th…