Search results for " calcium channel"
showing 10 items of 64 documents
Diacylglycerol-containing oleic acid induces increases in [Ca(2+)](i) via TRPC3/6 channels in human T-cells.
2011
Though most of the studies have focused on the effects of free fatty acids on T-cell activation, fatty acids incorporated into plasma membrane phospholipids may also affect cell signaling via diacylglycerol (DAG), generally produced by phospholipid hydrolysis. In the present study, we have synthesized a DAG-containing oleic acid and studied its implication in the modulation of calcium signaling in human Jurkat T-cells. 1-palmitoyl-2-oleoyl-sn-glycerol (POG) induced a dose-dependent increase in [Ca(2+)](i). This effect was due to the presence of oleic acid at the sn-2 position as no differences were observed between POG and 1-stearoly-2-oleoyl-sn-glycerol (SOG). However, the substitution of …
Modulation of intracellular calcium concentrations and T cell activation by prickly pear polyphenols.
2004
Opuntia ficus indica (prickly pear) polyphenolic compounds (OFPC) triggered an increase in [Ca2+]i in human Jurkat T-cell lines. Furthermore, OFPC-induced rise in [Ca2+]i was significantly curtailed in calcium-free buffer (0% Ca2+) as compared to that in 100% Ca2+ medium. Preincubation of cells with tyrphostin A9, an inhibitor of Ca2+ release-activated Ca2+ (CRAC) channels, significantly diminished the OFPC-induced sustained response on the increases in [Ca2+]i. Lanthanum and nifedipine, the respective inhibitors of voltage-dependent and L-type calcium channels, failed to curtail significantly the OFPC-induced calcium response. As OFPC still stimulated increases in [Ca2+]i in 0% Ca2+ medium…
Regulation of calcium signalling by docosahexaenoic acid in human T-cells: implication of CRAC channels
2000
Abstract We elucidated the role of docosahexaenoic acid (DHA) on the increases in free intracellular calcium concentrations, [Ca2+]i, in human (Jurkat) T-cell lines. DHA evoked an increase in [Ca2+]i in a dose-dependent manner in these cells. Anti-CD3 antibody, known to stimulate increases in Ca2+ from endoplasmic reticulum (ER) via the production of inositol trisphosphate, also evoked increases in [Ca2+]i in Jurkat T-cells. We also used thapsigargin which inhibits Ca2+-ATPase of the ER and, therefore, increases Ca2+ in the cytosol. Interestingly, addition of DHA during the thapsigargin-induced peak response exerted an additive effect on the increases in [Ca2+]i in human T-cells, indicating…
Astrocytic potassium and calcium channels as integrators of the inflammatory and ischemic CNS microenvironment.
2021
Abstract Astrocytes are key regulators of their surroundings by receiving and integrating stimuli from their local microenvironment, thereby regulating glial and neuronal homeostasis. Cumulating evidence supports a plethora of heterogenic astrocyte subpopulations that differ morphologically and in their expression patterns of receptors, transporters and ion channels, as well as in their functional specialisation. Astrocytic heterogeneity is especially relevant under pathological conditions. In experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), morphologically distinct astrocytic subtypes were identified and could be linked to transcriptome changes dur…
(±)- BIGI-3h: Pentatarget-Directed Ligand combining Cholinesterase, Monoamine Oxidase, and Glycogen Synthase Kinase 3β Inhibition with Calcium Channe…
2021
Multitarget-directed ligands (MTDLs) are considered a promising therapeutic strategy to address the multifactorial nature of Alzheimer's disease (AD). Novel MTDLs have been designed as inhibitors of human acetylcholinesterases/butyrylcholinesterases, monoamine oxidase A/B, and glycogen synthase kinase 3β and as calcium channel antagonists via the Biginelli multicomponent reaction. Among these MTDLs, (±)-BIGI-3h was identified as a promising new hit compound showing in vitro balanced activities toward the aforementioned recognized AD targets. Additional in vitro studies demonstrated antioxidant effects and brain penetration, along with the ability to inhibit the aggregation of both τ protein…
Molecular basis of early epithelial response to streptococcal exotoxin: role of STIM1 and Orai1 proteins
2011
Streptolysin O (SLO) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pyogenes. SLO induces diverse types of Ca(2+) signalling in host cells which play a key role in membrane repair and cell fate determination. The mechanisms behind SLO-induced Ca(2+) signalling remain poorly understood. Here, we show that in NCI-H441 cells, wild-type SLO as well as non-pore-forming mutant induces long-lasting intracellular Ca(2+) oscillations via IP(3) -mediated depletion of intracellular stores and activation of store-operated Ca(2+) (SOC) entry. SLO-induced activation of SOC entry was confirmed by Ca(2+) add-back experiments, pharmacologically and by overexpression as well as silencing of ST…
Alteration of loosely bound calcium in the guinea pig organ of Corti after treatment with diltiazem as calcium channel blocker
1997
After oral administration of the organic calcium channel blocker diltiazem to guinea pigs for 7 days, calcium ions were precipitated with potassium antimonate in the cochleae. The spatial distribution of the precipitates was studied by energy-filtering transmission electron microscopy and the amount of the ultrastructural reaction products formed was determined semiquantitatively by an image processing system. Compared with untreated control ears, the number of the formed precipitates was reduced drastically in the inner hair cells after diltiazem treatment. In addition, electron microscopic analysis revealed that the number of calcium precipitates attached at the basolateral membrane of th…
Effect of inhibition of the electrogenic Na+/K+ pump on the mechanical activity in the rat uterus.
1996
The effects of ouabain and K(+)-free solution were studied in estrogen-primed rat uterine strips under resting tone or repeatedly stimulated with KCl, acetylcholine or oxytocin applied for 20 minutes at 60 minute intervals. These effects were compared with those of the K+ channel opener cromakalim. In preparations under resting tone, ouabain (0.1 mM and 0.3 mM) induced rhythmic contractions which disappeared after 20-30 minutes whereas at a higher concentration (1 mM) it evoked a rapid, phasic response followed by a small tonic contraction. Exposure of the strip to a K(+)-free solution induced either rhythmic waves, which ceased after 8-10 minutes, or a single phasic contraction which was f…
Surgical sphincter saving approach and topical nifedipine for chronic anal fissure with hypertonic internal anal sphincter
2020
PURPOSE The role of augmented internal anal sphincter (IAS) tone in the genesis of posterior chronic anal fissure (CAPF) is still unknown. Lateral internal sphincterotomy is the most employed surgical procedure, nevertheless it is burdened by high risk post-operative anal incontinence. The aim of our study is to evaluate results of sphincter saving procedure with post-operative pharmacological sphincterotomy for patients affected by CAPF with IAS hypertonia. Methods: We enrolled 30 patients, undergone fissurectomy and anoplasty with V-Y cutaneous flap advancement; all patients received topical administration of nifedipine 0.3% and lidocaine 1.5% ointment-based therapy before and for 15 days…
The influence of Ca2+ antagonists on the ciliary activity of the guinea pig trachea.
1990
The ciliary activity of the guinea pig tracheal respiratory epithelium was measured using a photoelectric device. Fourteen animals were administered 75 mg diltiazem/kg body weight 2 days, 1 day and 4 h prior to the investigation. Thirteen animals served as controls. In the pretreated group, the mean ciliary stroke frequency (13.4 +/- 3.0 Hz) was significantly lower (P = 0.02) than in the control group (16.6 +/- 3.7 Hz). The application of aerosolized 0.3 mmol/l nifedipine solution on the tracheal preparations of the control animals also significantly reduced the stroke frequency (P = 0.02). The ciliary activity never dropped beyond a frequency of about 8 Hz. The most probable interpretation…