Search results for "Rini"
showing 10 items of 746 documents
Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in …
1997
1 The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M-2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M-2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference.2 It was found that tripitramine antagonized …
Endothelial and neural factors functionally involved in the modulation of noradrenergic vasoconstriction in healthy pig internal mammary artery
2011
The role of endothelial and neural factors as modulators of neurogenic- and noradrenaline-induced vasoconstriction was examined in healthy pig internal mammary artery (IMA). Tetrodotoxin-, guanethidine-sensitive electrical field stimulation (EFS)-, and noradrenaline-elicited contractions were significantly diminished by prazosin (n=8, P0.001) and less so by rauwolscine, indicating functional α₁- and α₂-adrenoceptor-mediated noradrenergic innervation of the IMA. Endothelium removal reduced neurogenic (n=8, P0.01) but augmented noradrenaline responses (n=8, P0.01), suggesting the release of two endothelium-dependent factors with opposite effects. In the presence of endothelium, neurogenic and…
Endogenous noradrenaline release from guinea-pig isolated trachea is inhibited by activation of M2 receptors
1992
Overflow of endogenous noradrenaline (NA) from guinea-pig isolated tracheae was evoked by electrical field stimulation (3 Hz, 540 pulses). The muscarinic receptor agonist oxotremorine inhibited the evoked overflow of NA in a concentration-dependent manner (EC50 84 nM). Methoctramine, pirenzepine and p-fluoro-hexahydrosiladiphenidol (each 1 microM) shifted the concentration-response curves of oxotremorine to the right with apparent pA2 values of 7.60, 6.74 and 6.18, respectively. It is concluded that sympathetic nerve terminals in the guinea-pig trachea are endowed with inhibitory muscarinic M2 receptors.
The effects of several muscarinic antagonists on pre- and postsynaptic receptors in the isolated rabbit heart
1981
In order to reveal possible differences between pre- and postsynaptic muscarine receptors, seven antagonists were tested for their affinities on these receptor sites in the rabbit isolated perfused heart. Methacholine was used as an agonist to inhibit the noradrenaline overflow evoked by electrical stimulation (3 Hz, 3 min) of the sympathetic nerves (presynaptic parameter) and to decrease the systolic tension development of the right atrium (postsynaptic parameter). The affinity of an antagonist was expressed as pA2. A decreasing order of potency was obtained with ipratropium, scopolamine, atropine, trihexyphenidyl, amitriptyline, and gallamine, both for pre- and postsynaptic responses. The…
Effects of a water-soluble extract of rosemary and its purified component rosmarinic acid on xenobiotic-metabolizing enzymes in rat liver
2001
The effects of a water-soluble extract (WSE) of rosemary and its purified antioxidant rosmarinic acid (RA) on xenobiotic metabolizing enzymes (XME) were studied in rat liver after dietary administration. The modulation of phase I enzymes such as cytochrome P450 (CYP) 1A, 2B, 2E1, 3A, and phase II enzymes such as glutathione S-transferase (GST), quinone reductase (QR) and UDP-glucuronosyltransferase (UGT) was evaluated by measuring enzyme activities with specific substrates. Protein levels of CYPs and rGST A1/A2, A3/A5, M1, M2 and P1 were measured using antibodies in Western blots. Caffeic acid was also studied because it results from RA biotransformation in rat after oral administration. Ma…
Tea catechins induce crosstalk between signaling pathways and stabilize mast cells in ulcerative colitis
2017
It is well documented that nutraceuticals, in general, and Green tea catechins, in particular, possess a potential therapeutic value in inflammatory bowel diseases (IBD) due to their anti-oxidative and anti-inflammatory effects. This study aimed to investigate the possible mechanism of action of catechins in a rat model of colitis induced by 2.4.6 trinitrobenzene sulfonic acid (TNBS). Thirty-five young adult Sprague-Dawley rats were divided into four groups: normal control (n=5), catechins (n=9), TNBS (n=9) and TNBS plus catechins (n=12) treated. Catechin in the form of Epigallocatechin-3-gallate (EGCG) was administered daily by intraperitoneal injection, 1 week before the induction date of…
Mechanistic basis for unexpected bioavailability enhancement of polyelectrolyte complexes incorporating BCS class III drugs and carrageenans
2013
The objective of this study was to investigate the potential of λ-carrageenan to work as an absorption modifying excipient in combination with formulations of BCS class 3 substances. Trospium chloride was used as a model BCS class 3 substance. Polyelectrolyte complexes of trospium and λ-carrageenan were produced by layer-by-layer complexation. A λ-carrageenan-containing formulation was administered either in capsules size 9 to rats by gavage or directly into ligated intestinal loops of rats. Exceptionally strong variations were observed in the plasma concentrations of the rats that received λ-carrageenan compared to the control group, but enhanced plasma concentrations were observed only in…
Bacteria-Derived Compatible Solutes Ectoine and 5α-Hydroxyectoine Act as Intestinal Barrier Stabilizers to Ameliorate Experimental Inflammatory Bowel…
2015
Earlier studies showed that the compatible solute ectoine (1) given prophylactically before induction of colitis by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats prevented histological changes induced in the colon and the associated rise in inflammatory mediators. This study was therefore conducted to investigate whether ectoine (1) and its 5α-hydroxy derivative (2) would also be effective in treating an already established condition. Two days after inducing colitis in rats by instilling TNBS/alcohol in the colon, animals were treated orally once daily for 1 week with either 1 or 2 (50, 100, 300 mg/kg). Twenty-four hours after the last drug administration rats were sacrificed. Ulcerativ…
Probiotic mixture supplementation in the preventive management of trinitrobenzenesulfonic acid-induced inflammation in a murine model
2016
Inflammatory bowel diseases (IBD) are characterized by inflammatory conditions of the intestine. Probiotic bacteria (PB) can have beneficial effects in several gastrointestinal disorders. The objectives of this study were: (i) to provide an acute experimental IBD model induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in CD-1 mice, and (ii) to assess the preventive effects of Citogenex (Lactobacillus casei and Bifidobacterum lactis) supplementation on intestinal tissues and microbiota. Mice were inoculated intrarectally with saline, ethanol or different TNBS solutions. 1%TNBS induced clinical signs of colitis (P less than 0.01) and histological damage (P less than 0.01). Based on these r…
HIF-Overexpression and Pro-Inflammatory Priming in Human Mesenchymal Stromal Cells Improves the Healing Properties of Extracellular Vesicles in Exper…
2021
Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have therapeutic potential in the treatment of several immune disorders, including ulcerative colitis, owing to their regenerative and immunosuppressive properties. We recently showed that MSCs engineered to overexpress hypoxia-inducible factor 1-alpha and telomerase (MSC-T-HIF) and conditioned with pro-inflammatory stimuli release EVs (EVMSC-T-HIFC) with potent immunomodulatory activity. We tested the efficacy of EVMSC-T-HIFC to repolarize M1 macrophages (Mφ1) to M2-like macrophages (Mφ2-like) by analyzing surface markers and cytokines and performing functional assays in co-culture, including efferocytosis and T-cel…