Search results for "toxin"
showing 10 items of 1434 documents
Interplay between PACAP and NO in mouse ileum
2003
Abstract We investigated the possibility that pituitary adenylate cyclase activating peptide (PACAP) has a role in the control of contractility in the mouse ileum. PACAP-(1-27) produced tetrodotoxin (TTX)-insensitive, concentration-dependent reduction of the amplitude of the spontaneous contractions of longitudinal muscle up to their complete disappearance. This effect was inhibited by PACAP-(6-38), PACAP receptor antagonist, and by apamin, blocker of small-conductance Ca2+-activated K+-channels. Nω-nitro- l -arginine methyl ester (L-NAME), nitric oxide (NO) synthase inhibitor, reduced the PACAP-inhibitory response, and the joint application of apamin plus L-NAME produced additive effects. …
A1 receptors mediate adenosine inhibitory effects in mouse ileum via activation of potassium channels.
2008
Abstract Aims We investigated the effects induced by exogenous adenosine on the spontaneous contractile activity of the longitudinal muscle of a mouse ileum, the receptor subtypes activated, the involvement of enteric nerves and whether opening of K + channels was a downstream event leading to the observed effects. Main methods Mechanical responses of the mouse ileal longitudinal muscle to adenosine were examined in vitro as changes in isometric tension. Key findings Adenosine caused a concentration-dependent reduction of the spontaneous contraction amplitude of the ileal longitudinal muscle up to its complete disappearance. This effect induced was markedly reduced by an A 1 receptor antago…
Haemolytic-uremic syndrome due to infection with adenovirus
2018
Abstract Rationale: Haemolytic-uremic syndrome is a rare but serious complication of bacterial and viral infections, which is characterized by the triad of: acute renal failure, microangiopathic haemolytic anemia and thrombocytopenia, sometimes severe, requiring peritoneal dialysis. In Europe, hemolytic-uremic syndrome (HUS) in paediatric pathology is primarily caused by Shiga toxin-producing Escherichia coli (STEC) O157, followed by O26. Beside these etiologies, there are other bacterial and viral infections, and also noninfectious ones that have been associated to lead to HUS as well: in the progression of neoplasia, medication-related, post-transplantation, during pregnancy or associated…
Involvement of endogenous nitric oxide in the inhibition by endotoxin and interleukin-1 beta of gastric acid secretion.
1994
Administration of Escherichia coli endotoxin abolished the acid secretory response induced by a bolus injection of pentagastrin in the continuously perfused stomach of the anaesthetized rat. Likewise, acid secretion stimulated by the continuous intravenous perfusion of pentagastrin was inhibited by administration of interleukin-1 beta (IL-1 beta). In both cases pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) but not dexamethasone or indomethacin substantially restored the secretory responses to pentagastrin. The actions of L-NAME were reversed by the prior administration of L-arginine but not by its enantiomer D-arginine. Even though L-NAME increased blood pressure, this does no…
Cholinergic and GABAergic regulation of nitric oxide synthesis in the guinea pig ileum.
1999
Nitric oxide (NO) synthesis was examined in intact longitudinal muscle-myenteric plexus preparations of the guinea pig ileum by determining the formation of [3H]citrulline during incubation with [3H]arginine. Spontaneous [3H]citrulline production after 30 min was 80–90 dpm/mg, which constituted ∼1% of the tissue radioactivity. Electrical stimulation (10 Hz) led to a threefold increase in [3H]citrulline formation. Removal of calcium from the medium or addition of N G-nitro-l-arginine strongly inhibited both spontaneous and electrically induced production of [3H]citrulline. TTX reduced the electrically induced but not spontaneous [3H]citrulline formation. The electrically induced formation o…
The anti-CD14 antibody IC14 suppresses ex vivo endotoxin stimulated tumor necrosis factor-alpha in patients with chronic heart failure
2006
Background: Activation of the endotoxin (LPS) receptor, CD14, leads to tumor necrosis factor-alpha (TNF) production. Plasma LPS activity is elevated in patients with severe chronic heart failure (CHF). An anti-CD14 antibody, IC14, blocks TNF production in healthy volunteers. It is not known whether IC14 prevents TNF production in CHF patients. Methods and results: Blood from 20 CHF patients (age 64±2.1 years, NYHA class 2.2±0.1, LVEF 27±3%, mean±SEM) was pre-incubated with 0.5, 1.0, 5.0, 10 and 50 μg/mL IC14 for 1 h followed by incubation with 1 or 10 ng/mL LPS for 6 h. Fourteen subjects served as controls (58±2.4 years). LPS-stimulated TNF release was 76% and 60% greater at 1 and 10 ng/mL …
Role of K+ and Ca2+ fluxes in the cerebroarterial vasoactive effects of sildenafil
2007
The aim of this study was to assess the role of K(+) and Ca(2+) fluxes in the cerebroarterial vasoactive effects of the phosphodiesterase-5 inhibitor sildenafil. We used isolated rabbit basilar arteries to assess the effects of extracellular K(+) raising on sildenafil-induced vasodilatation, and studied the pharmacological interaction of sildenafil with selective modulators of membrane K(+) and Ca(2+) channels. Expression of Kv1 subunits of K(+) channels was assessed at messenger and protein levels. Parallel experiments were carried out with zaprinast for comparison. Sildenafil (10 nM-0.1 mM) induced concentration-dependent relaxation of endothelin-1 (10 nM)-precontracted arteries, which wa…
Botulinum Toxin Type B Blocks Sudomotor Function Effectively: A 6 Month Follow Up
2003
This study analyzes the suppression of sweat gland activity by botulinum toxin type B. We injected botulinum toxin type B (between 2 and 1000 mouse units subcutaneously) in the lateral side of both lower legs in 15 healthy volunteers. Sweat tests were carried out before botulinum toxin type B injections, and at 3 wk, 3 mo, and 6 mo. We studied focal anhidrosis by iodine–starch staining and by capacitance hygrometry after carbachol iontophoresis, according to the quantitative sudomotor axon reflex test (QSART). Iodine starch staining indicated that a threshold dose of 8 mouse units botulinum toxin type B leads to anhidrotic skin spots (>4 cm2) after 3 wk. Duration of anhidrosis was prolonged…
Tetrodotoxin-dependent effects of menthol on mouse gastric motor function.
2013
Menthol, the main active constituent of peppermint oil, exerts gut spasmolytic effects, although its mechanism of action remains unclear. We investigated the effects of menthol on gastric emptying and spontaneous- or evoked- mechanical activity of whole murine stomach. Gastric emptying was calculated after i.p. administration of menthol (50mg/Kg). Responses induced by menthol on gastric intraluminal pressure and evoked-cholinergic contractions were analyzed in vitro. Menthol decreased the gastric emptying rate. In vitro, menthol (0.3-30 mM) produced a concentration-dependent relaxation of whole stomach, that was significantly reduced by tetrodotoxin or ω-conotoxin GVIA. The gastric relaxant…
Effect of beta-N-oxalylamino-L-alanine on cerebellar cGMP level in vivo.
1993
Beta-N-oxalylamino-L-alanine (BOAA), a non-protein amino acid present in the seeds of Lathyrus Sativus (LS), is one of several neuroactive glutamate analogs reported to stimulate excitatory receptors and, in high concentrations, cause neuronal degeneration. In the present study, the in vivo acute effects of synthetic BOAA and LS seed extract were investigated on rat cerebellar cyclic GMP following intraperitoneal (10-100 mg/kg) or oral (100 mg/kg) administration of subconvulsive doses of toxin. Furthermore, the BOAA content in LS seeds and in the cerebellum of injected rats was determined by high performance liquid chromatograph analysis. A dose- and time-dependent increase of cerebellar cy…