Search results for "Calcium"
showing 10 items of 1740 documents
On the mechanism of action of phenylephrine in rat atrial heart muscle
1994
Both in rat left atrial heart and in aortic smooth muscle preparations, phenylephrine (PE) caused a concentration-dependent increase in force of contraction (FC) in the presence of atenolol (10 mumol/l), which was antagonized by phentolamine, prazosin and WB 4101 in a competitive manner. The pA2 values of the antagonists in the cardiac tissue were 10-20fold lower than those in the rat thoracic aorta. In the spontaneously beating right atrium, PE exerted a positive chronotropic action, which was not significantly antagonized by phentolamine or prazosin. It is therefore assumed that the effects of phenylephrine in the left atrium and in the aorta are mediated by different subtypes of alpha 1-…
Calcium antagonist properties of cinnarizine, trifluoperazine and verapamil in guinea-pig normal and skinned trachealis muscle.
1990
In guinea-pig trachealis, depolarized by a K(+)-rich medium, Ca2+ (0.01-10 mM) caused concentration-related spasm. Verapamil (0.5-5 microM), cinnarizine (10-100 microM) and trifluoperazine (16-160 microM) each produced concentration-dependent antagonism of Ca2+ characterized by a rightward and downward displacement of the log concentration-effect curve for Ca2+. The rank order of potencies of these antagonists, measured as the IC75 against Ca2+ (10 mM)-induced contraction of depolarized trachea, was verapamil (5.6 microM) greater than cinnarizine (59 microM) greater than trifluoperazine (91 microM). In skinned trachea, verapamil in concentrations up to 100 microM did not modify the concentr…
Complete congenital heart block is associated with increased autoantibody titers against calreticulin.
1996
Complete congenital heart block (CCHB) is associated with anti-Ro/SS-A and anti-La/SS-B antibodies. Calreticulin, a calcium-binding, multi-functional protein of the endoplasmic reticulum with C-terminal KDEL-sequence, is not part of the Ro/SS-A ribonucleoprotein complex. In this study anti-calreticulin autoantibody responses in serum samples from 18 infants with CCHB, their mothers and in a control group of 11 anti-Ro/SS-A or anti-La/SS-B positive infants without heart block and their mothers were analysed. Specific enzyme-linked immunosorbent assays were performed. Nine out of 18 sera with CCHB contained IgG anti-calreticulin antibodies. Four sera of those with IgG antibodies also had IgM …
Pretreatment with potent P-glycoprotein ligands may increase intestinal secretion in rats.
2001
The expression of P-glycoprotein is induced in cell cultures upon exposure to various inducers. Therefore, the aim of the present study was to evaluate the in-vivo relevance of this observation, i.e. the influence of chronic pretreatments with selected drugs -- all of which are ligands to P-glycoprotein (P-gp) as demonstrated in radioligand binding studies and all of which have some or a considerable effect on P-gp expression in Caco-2 cells -- on the effective intestinal permeabilities of the model compound talinolol in rats employing in-situ single-pass intestinal perfusion of three different gut segments. Talinolol was selected, because it shows high selectivity for one of the exsorptive…
Transcriptional profiling reveals functional links between RasGrf1 and Pttg1 in pancreatic beta cells
2014
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License .
Postnatal increases in axonal conduction velocity of an identified Drosophila interneuron require fast sodium, L-type calcium and shaker potassium ch…
2019
Abstract During early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in the Drosophila giant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelina…
Effects of Calcium Antagonists on Rat Normal and Skinned Fundus
1992
Abstract Calcium chloride (CaCl2) (0·1−25 Mm, in K+-depolarized tissue), KCl (10−112 Mm) and acetylcholine (1 × 10−9 m−1 Mm) produced concentration-dependent contractions of rat isolated fundus. Verapamil (0·01−100 μm), cinnarizine (1−100 μm), trifluoperazine (10−500 μm) and dantrolene (50−250 μm) each produced a concentration-related rightward and downward shift of the log concentration-effect curve for CaCl2. The rank order of potencies of these antagonists, measured as the IC50 against Ca2+ (25 Mm)-induced contraction of depolarized fundus, was verapamil (2.5 μm) > cinnarizine (8·7 μm) > trifluoperazine (85·1 μm) > dantrolene (> 250 μm). Cinnarizine (0·5 Mm) a…
Effect of dantrolene sodium in isolated guinea-pig trachea.
1990
The effect of dantrolene sodium (3 microM-0.3 mM) on the spontaneous tone and responses to various contractile agonists was studied in isolated guinea-pig trachea. Dantrolene produced a concentration-related inhibition of the spontaneous tracheal tone, reaching a value of 94.8 +/- 4.8% of the relaxation induced by caffeine 10 mM. Removal of the epithelium did not affect the dantrolene-induced relaxation. Dantrolene did not alter the concentration-response curve for KCl and produced only small displacements of the concentration-response curves for CaCl2, acetylcholine and histamine, without affecting their maximal effects. Dantrolene dose relatedly inhibited the contraction induced by caffei…
Quantification of epicardial adipose tissue in coronary calcium score and CT coronary angiography image data sets: comparison of attenuation values, …
2016
The aim of the study was to compare epicardial adipose tissue (EAT) characteristics assessed with coronary calcium score (CS) and CT coronary angiography (CTCA) image data sets.In 76 patients (mean age 59 ± 13 years) who underwent CS and CTCA owing to suspected coronary artery disease (CAD), EAT was quantified in terms of density (Hounsfield units), thickness and volume. The EAT volume was extracted with a semi-automatic software.A moderate correlation was found between EAT density in CS and CTCA image data sets (-100 ± 19 HU vs -70 ± 24 HU; p 0.05, r = 0.55). The distribution of EAT was not symmetrical with a maximal thickness at the right atrioventricular groove (14.2 ± 5.3 mm in CS, 15.…
Is there association between chronic kidney disease and dental caries? A case-controlled study
2018
Background The purpose of this study was to assess the association between chronic kidney diseases (CKD) and dental caries. Material and Methods 107 patients with CKD and 107 with no systemic alteration were randomly included. DMFT (decayed, missing, and filled teeth), plaque index, colony-forming units (CFU) of Streptococcus mutans and salivary composition (IgA total, IgA anti- Streptococcus mutans, calcium and urea) were evaluated. McNemar and Wilcoxon tests were used to compare test and control groups. Spearman test was used to correlate time of hemodialysis and variables studied. Associations between variables were evaluated by logistic regression analysis. Results The number of filled …