Search results for "Calcium signal"
showing 10 items of 97 documents
Cortex-wide BOLD fMRI activity reflects locally-recorded slow oscillation-associated calcium waves.
2017
When a person is in a deep non-dreaming sleep, neurons in their brain alternate slowly between periods of silence and periods of activity. This gives rise to low-frequency brain rhythms called slow waves, which are thought to help stabilize memories. Slow wave activity can be detected on multiple scales, from the pattern of electrical impulses sent by an individual neuron to the collective activity of the brain’s entire outer layer, the cortex. But does slow wave activity in an individual group of neurons in the cortex affect the activity of the rest of the brain? To find out, Schwalm, Schmid, Wachsmuth et al. took advantage of the fact that slow waves also occur under general anesthesia, a…
Functional Gustatory Role of Chemoreceptors in Drosophila Wings
2016
Summary: Neuroanatomical evidence argues for the presence of taste sensilla in Drosophila wings; however, the taste physiology of insect wings remains hypothetical, and a comprehensive link to mechanical functions, such as flight, wing flapping, and grooming, is lacking. Our data show that the sensilla of the Drosophila anterior wing margin respond to both sweet and bitter molecules through an increase in cytosolic Ca2+ levels. Conversely, genetically modified flies presenting a wing-specific reduction in chemosensory cells show severe defects in both wing taste signaling and the exploratory guidance associated with chemodetection. In Drosophila, the chemodetection machinery includes mechan…
Ca2+ signalling plays a role in celastrol‐mediated suppression of synovial fibroblasts of rheumatoid arthritis patients and experimental arthritis in…
2019
Background and purpose Celastrol exhibits anti-arthritic effects in rheumatoid arthritis (RA), but the role of celastrol-mediated Ca2+ mobilization in treatment of RA remains undefined. Here, we describe a regulatory role for celastrol-induced Ca2+ signalling in synovial fibroblasts of RA patients and adjuvant-induced arthritis (AIA) in rats. Experimental approach We used computational docking, Ca2+ dynamics and functional assays to study the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase pump (SERCA). In rheumatoid arthritis synovial fibroblasts (RASFs)/rheumatoid arthritis fibroblast-like synoviocytes (RAFLS), mechanisms of Ca2+ -mediated autophagy were analysed by histological, immunohis…
More than a pore: How voltage-gated calcium channels act on different levels of neuronal communication regulation.
2021
ABSTRACT Voltage-gated calcium channels (VGCCs) represent key regulators of the calcium influx through the plasma membrane of excitable cells, like neurons. Activated by the depolarization of the membrane, the opening of VGCCs induces very transient and local changes in the intracellular calcium concentration, known as calcium nanodomains, that in turn trigger calcium-dependent signaling cascades and the release of chemical neurotransmitters. Based on their central importance as concierges of excitation-secretion coupling and therefore neuronal communication, VGCCs have been studied in multiple aspects of neuronal function and malfunction. However, studies on molecular interaction partners …
Disarrangement of Endoplasmic reticulum-mitochondria communication impairs Ca2+ homeostasis in FRDA
2020
AbstractFriedreich ataxia (FRDA) is a neurodegenerative disorder characterized by neuromuscular and neurological manifestations. It is caused by mutations in gene FXN, which results in loss of the mitochondrial protein frataxin. Endoplasmic Reticulum-mitochondria associated membranes (MAMs) are inter-organelle structures involved in the regulation of essential cellular processes, including lipid metabolism and calcium signaling. In the present study, we have analyzed in both, unicellular and multicellular models of FRDA, an analysis of calcium management and of integrity of MAMs. We observed that function of MAMs is compromised in our cellular model of FRDA, which was improved upon treatmen…
Natural Proteolytic Processing of Hemofiltrate Cc Chemokine 1 Generates a Potent Cc Chemokine Receptor (Ccr)1 and Ccr5 Agonist with Anti-HIV Properti…
2000
Hemofiltrate CC chemokine (HCC)-1 is a recently described human chemokine that is constitutively expressed in numerous tissues and is present at high concentrations in normal plasma. Using a cell line expressing CC chemokine receptor (CCR)5 as a bioassay, we isolated from human hemofiltrate an HCC-1 variant lacking the first eight amino acids. HCC-1[9–74] was a potent agonist of CCR1, CCR3, and CCR5 and promoted calcium flux and chemotaxis of T lymphoblasts, monocytes, and eosinophils. It also blocked entry of HIV-1 strains using CCR5 as coreceptor. Limited tryptic digestion of HCC-1 generated the active variant. Conditioned media from several tumor cell lines activated HCC-1 with a high ef…
Impaired calcium homeostasis in aged hippocampal neurons
2009
Abstract Development of neurodegenerative diseases such as Alzheimer's and Parkinson's disease is strongly age-associated. The impairment of calcium homeostasis is considered to be a key pathological event leading to neuronal dysfunction and cell death. However, the exact impact of aging on calcium homeostasis in neurons remains largely unknown. In the present work we have investigated intracellular calcium levels in cultured primary hippocampal neurons from young (2 months) and aged (24 months) rat brains. Upon stimulation with glutamate or hydrogen peroxide aged neurons in comparison to young neurons demonstrated an increased vulnerability to these disease-related toxins. Measurement of c…
Agonist potency differentiates G protein activation and Ca2+ signalling by the orexin receptor type 1.
2005
The G protein coupling characteristics of a flag epitope-tagged orexin receptor type 1 (OX1R) was investigated in HEK293 cells. Immunoprecipitation of the OX1R and immunoblotting revealed interactions with Gq/G11 proteins as well as with Gs and Gi proteins. Stimulation with orexin-A did not affect the ability of the OX1R to coprecipitate Gq/G11 proteins, but it robustly elevated the intracellular concentration of Ca2+, [Ca2+]i. No changes in cAMP levels could be detected upon receptor stimulation. To get further insight into the functional correlation of G protein activation and Ca2+ signalling, we used baculovirus transduction to express chimeric G proteins, containing the Galphas protein …
5-HT3 receptor-channels coupled with Na+ influx in human T cells: role in T cell activation.
1999
The study was conducted on a human (Jurkat) T cell line, loaded with a Na+ fluorescent probe, SBFI/AM. Serotonin and an agonist of 5-HT3 receptor-channels, 2-methyl-5HT, evoked Na+ influx, whereas the agonists of other serotonergic receptor subtypes, i.e., 5-HT1A and 5-HT1B receptors, failed to induce Na+ influx in these cells. By using 3H-BRL43694, an agonist of 5-HT3 receptor-channels, we characterized 5-HT3 lymphocyte receptors which exhibited a density (Bmax) of 300 +/- 20 fmol/10(6) cells and a Kd of 30 nM in Jurkat T cells. The T-cell 5-HT3 receptor-channel is not regulated either by the protein kinase C or by the free intracellular calcium concentrations as the agents known to activa…
Role of calcium in E-selectin induced phenotype of T84 colon carcinoma cells
2003
The adhesion of cancer cells to the endothelium during the metastatic process involves the interaction of specific cell-cell adhesion receptors on the cell surface. E-selectin on endothelial cells and sialyl Lewis X carbohydrate component on tumor cells are mainly implicated in the adhesion of colon carcinoma cells to the endothelium of target organ. In this paper we show that binding of E-selectin to T84 colon tumor cells causes approximately a twofold increase in intracellular calcium concentration. In particular, using two inhibitors of receptor operated calcium channels, CAI and SK&F 96365, we present evidences that the augmentation in cytoplasmic calcium originates from ionic influx fr…