نتائج البحث - "MUSCARINIC agonists"

1

دورية أكاديمية

Oscillatory calcium release and sustained store-operated oscillatory calcium signaling prevents differentiation of human oligodendrocyte progenitor cells.

المؤلفون: Seidman, Richard A.¹ (AUTHOR), Khattab, Heba² (AUTHOR), Polanco, Jessie J.¹ (AUTHOR), Broome, Jacqueline E.² (AUTHOR), Sim, Fraser J.^1,2 (AUTHOR) fjsim@buffalo.edu

المصدر: Scientific Reports. 4/13/2022, Vol. 12 Issue 1, p1-19. 19p.

مصطلحات موضوعية: *PROGENITOR cells, *MUSCARINIC agonists, *CALCIUM, *GLUTAMATE receptors, *MUSCARINIC receptors, *FREQUENCIES of oscillating systems, *INTRACELLULAR calcium

مستخلص: Endogenous remyelination in demyelinating diseases such as multiple sclerosis is contingent upon the successful differentiation of oligodendrocyte progenitor cells (OPCs). Signaling via the Gαq-coupled muscarinic receptor (M1/3R) inhibits human OPC differentiation and impairs endogenous remyelination in experimental models. We hypothesized that calcium release following Gαq-coupled receptor (GqR) activation directly regulates human OPC (hOPC) cell fate. In this study, we show that specific GqR agonists activating muscarinic and metabotropic glutamate receptors induce characteristic oscillatory calcium release in hOPCs and that these agonists similarly block hOPC maturation in vitro. Both agonists induce calcium release from endoplasmic reticulum (ER) stores and store operated calcium entry (SOCE) likely via STIM/ORAI-based channels. siRNA mediated knockdown (KD) of obligate calcium sensors STIM1 and STIM2 decreased the magnitude of muscarinic agonist induced oscillatory calcium release and attenuated SOCE in hOPCs. In addition, STIM2 expression was necessary to maintain the frequency of calcium oscillations and STIM2 KD reduced spontaneous OPC differentiation. Furthermore, STIM2 siRNA prevented the effects of muscarinic agonist treatment on OPC differentiation suggesting that SOCE is necessary for the anti-differentiative action of muscarinic receptor-dependent signaling. Finally, using a gain-of-function approach with an optogenetic STIM lentivirus, we demonstrate that independent activation of SOCE was sufficient to significantly block hOPC differentiation and this occurred in a frequency dependent manner while increasing hOPC proliferation. These findings suggest that intracellular calcium oscillations directly regulate hOPC fate and that modulation of calcium oscillation frequency may overcome inhibitory Gαq-coupled signaling that impairs myelin repair. [ABSTRACT FROM AUTHOR]

النص الكامل

2

دورية أكاديمية

Rapid Throughput Analysis Demonstrates that Chemicals with Distinct Seizurogenic Mechanisms Differentially Alter Ca2+ Dynamics in Networks Formed by Hippocampal Neurons in Culture

المؤلفون: Cao, Zhengyu, Zou, Xiaohan, Cui, Yanjun, Hulsizer, Susan, Lein, Pamela J, Wulff, Heike, Pessah, Isaac N

المصدر: Molecular Pharmacology. 87(4)

الوصف: Primary cultured hippocampal neurons (HN) form functional networks displaying synchronous Ca(2+) oscillations (SCOs) whose patterns influence plasticity. Whether chemicals with distinct seizurogenic mechanisms differentially alter SCO patterns was investigated using mouse HN loaded with the Ca(2+) indicator fluo-4-AM. Intracellular Ca(2+) dynamics were recorded from 96 wells simultaneously in real-time using fluorescent imaging plate reader. Although quiescent at 4 days in vitro (DIV), HN acquired distinctive SCO patterns as they matured to form extensive dendritic networks by 16 DIV. Challenge with kainate, a kainate receptor (KAR) agonist, 4-aminopyridine (4-AP), a K(+) channel blocker, or pilocarpine, a muscarinic acetylcholine receptor agonist, caused distinct changes in SCO dynamics. Kainate at 1 µM kainate. KAR competitive antagonist CNQX [6-cyano-7-nitroquinoxaline-2,3-dione] (1-10 µM) normalized Ca(2+) dynamics to the prekainate pattern. Pilocarpine lacked Phase I activity but caused a sevenfold prolongation of Phase II SCOs without altering either their frequency or amplitude, an effect normalized by atropine (0.3-1 µM). 4-AP (1-30 µM) elicited a delayed Phase I response associated with persistent high-frequency, low-amplitude SCOs, and these disturbances were mitigated by pretreatment with the KCa activator SKA-31 [naphtho[1,2-d]thiazol-2-ylamine]. Consistent with its antiepileptic and neuroprotective activities, nonselective voltage-gated Na(+) and Ca(2+) channel blocker lamotrigine partially resolved kainate- and pilocarpine-induced Ca(2+) dysregulation. This rapid throughput approach can discriminate among distinct seizurogenic mechanisms that alter Ca(2+) dynamics in neuronal networks and may be useful in screening antiepileptic drug candidates.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/6x00n7fhTest
https://escholarship.org/content/qt6x00n7fh/qt6x00n7fh.pdfTest

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3

Oscillatory calcium release and sustained store-operated oscillatory calcium signaling prevents differentiation of human oligodendrocyte progenitor cells

المؤلفون: Richard A. Seidman, Heba Khattab, Jacqueline E. Broome, Jessie J. Polanco, Fraser J. Sim

المصدر: Scientific Reports. 12

الوصف: Endogenous remyelination in demyelinating diseases such as multiple sclerosis is contingent upon the successful differentiation of oligodendrocyte progenitor cells (OPCs). Signaling via the Gαq-coupled muscarinic receptor (M1/3R) inhibits human OPC differentiation and impairs endogenous remyelination in experimental models. We hypothesized that calcium release following Gαq-coupled receptor (GqR) activation directly regulates human OPC (hOPC) cell fate. In this study, we show that specific GqR agonists activating muscarinic and metabotropic glutamate receptors induce characteristic oscillatory calcium release in hOPCs and that these agonists similarly block hOPC maturation in vitro. Both agonists induce calcium release from endoplasmic reticulum (ER) stores and store operated calcium entry (SOCE) likely via STIM/ORAI-based channels. siRNA mediated knockdown (KD) of obligate calcium sensors STIM1 and STIM2 decreased the magnitude of muscarinic agonist induced oscillatory calcium release and attenuated SOCE in hOPCs. In addition, STIM2 expression was necessary to maintain the frequency of calcium oscillations and STIM2 KD reduced spontaneous OPC differentiation. Furthermore, STIM2 siRNA prevented the effects of muscarinic agonist treatment on OPC differentiation suggesting that SOCE is necessary for the anti-differentiative action of muscarinic receptor-dependent signaling. Finally, using a gain-of-function approach with an optogenetic STIM lentivirus, we demonstrate that independent activation of SOCE was sufficient to significantly block hOPC differentiation and this occurred in a frequency dependent manner while increasing hOPC proliferation. These findings suggest that intracellular calcium oscillations directly regulate hOPC fate and that modulation of calcium oscillation frequency may overcome inhibitory Gαq-coupled signaling that impairs myelin repair.Significance StatementIn this study, Seidman et al. show that SOCE is a common component of ligand-based Gαq-coupled signaling in hOPCs and that SOCE alone is sufficient to block hOPC differentiation and drive proliferation. Therefore, SOCE blocks differentiation and pathological SOCE could contribute to myelin disease.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::23ff30db00def53fc139b0a5520899ceTest
https://doi.org/10.1038/s41598-022-10095-1Test

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Biased Profile of Xanomeline at the Recombinant Human M

المؤلفون: Jack K, McDonald, Emma T, van der Westhuizen, Vi, Pham, Geoff, Thompson, Christian C, Felder, Steven M, Paul, David M, Thal, Arthur, Christopoulos, Celine, Valant

المصدر: ACS chemical neuroscience. 13(8)

مصطلحات موضوعية: Receptor, Muscarinic M4, Pyridines, Receptor, Muscarinic M1, CHO Cells, Muscarinic Agonists, Ligands, Receptors, Muscarinic, Acetylcholine, Receptors, G-Protein-Coupled, Cricetulus, Cricetinae, Thiadiazoles, Animals, Humans, Calcium

الوصف: Many Food and Drug Administration (FDA)-approved drugs are structural analogues of the endogenous (natural) ligands of G protein-coupled receptors (GPCRs). However, it is becoming appreciated that chemically distinct ligands can bind to GPCRs in conformations that lead to different cellular signaling events, a phenomenon termed biased agonism. Despite this, the rigorous experimentation and analysis required to identify biased agonism are often not undertaken in most clinical candidates and go unrealized. Recently, xanomeline, a muscarinic acetylcholine receptor (mAChR) agonist, has entered phase III clinical trials for the treatment of schizophrenia. If successful, xanomeline will be the first novel FDA-approved antipsychotic drug in almost 50 years. Intriguingly, xanomeline's potential for biased agonism at the mAChRs and, in particular, the M

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=pmid________::0eeff6cdb52d3ff0cd6b9d8c90af34cfTest
https://pubmed.ncbi.nlm.nih.gov/35380782Test

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Complex effects of eslicarbazepine on inhibitory micro networks in chronic experimental epilepsy

المؤلفون: Thoralf Opitz, Heinz Beck, Leonie Pothmann, Sarah Schmidt, Daniel Müller-Komorowska, Patrício Soares da Silva

المصدر: Epilepsia. 62:542-556

مصطلحات موضوعية: 0301 basic medicine, Long-Term Potentiation, Adamantane, AMPA receptor, Muscarinic Agonists, Hippocampal formation, Inhibitory postsynaptic potential, Hippocampus, 03 medical and health sciences, 0302 clinical medicine, Dibenzazepines, Interneurons, medicine, Animals, Receptors, AMPA, Receptor, CA1 Region, Hippocampal, Feedback, Physiological, Neurons, Epilepsy, Neuronal Plasticity, Dose-Response Relationship, Drug, Chemistry, Pyramidal Cells, Sodium channel, Pilocarpine, Neural Inhibition, Long-term potentiation, Carbamazepine, Rats, Disease Models, Animal, 030104 developmental biology, Inhibitory Postsynaptic Potentials, Neurology, Excitatory postsynaptic potential, Anticonvulsants, Calcium, Neurology (clinical), Neuroscience, 030217 neurology & neurosurgery, medicine.drug

الوصف: Objective Many antiseizure drugs (ASDs) act on voltage-dependent sodium channels, and the molecular basis of these effects is well established. In contrast, how ASDs act on the level of neuronal networks is much less understood. Methods In the present study, we determined the effects of eslicarbazepine (S-Lic) on different types of inhibitory neurons, as well as inhibitory motifs. Experiments were performed in hippocampal slices from both sham-control and chronically epileptic pilocarpine-treated rats. Results We found that S-Lic causes an unexpected reduction of feed-forward inhibition in the CA1 region at high concentrations (300 µM), but not at lower concentrations (100 µM). Concurrently, 300 but not 100 μM S-Lic significantly reduced maximal firing rates in putative feed-forward interneurons located in the CA1 stratum radiatum of sham-control and epileptic animals. In contrast, feedback inhibition was not inhibited by S-Lic. Instead, application of S-Lic, in contrast to previous data for other drugs like carbamazepine (CBZ), resulted in a lasting potentiation of feedback inhibitory post-synaptic currents (IPSCs) only in epileptic and not in sham-control animals, which persisted after washout of S-Lic. We hypothesized that this plasticity of inhibition might rely on anti-Hebbian potentiation of excitatory feedback inputs onto oriens-lacunosum moleculare (OLM) interneurons, which is dependent on Ca2+ -permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Indeed, we show that blocking Ca2+ -permeable AMPA receptors completely prevents upmodulation of feedback inhibition. Significance These results suggest that S-Lic affects inhibitory circuits in the CA1 hippocampal region in unexpected ways. In addition, ASD actions may not be sufficiently explained by acute effects on their target channels, rather, it may be necessary to take plasticity of inhibitory circuits into account.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::507b4cb6333175f4f008eacc8c175543Test
https://doi.org/10.1111/epi.16808Test

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Novel Insights Into Muscarinic and Purinergic Responses in Primary Cultures of Rat Lacrimal Gland Myoepithelial Cells

المؤلفون: Patrik Aronsson, Gunnar Tobin, Michael Winder, Thomas Carlsson, Martin Dankis

المصدر: Investigative Ophthalmology & Visual Science

الوصف: Purpose The functional characteristics of receptors that regulate lacrimal gland myoepithelial cells are still somewhat unclear. To date, mainly muscarinic receptors have been of interest; however, further knowledge is needed regarding their expression and functional roles. For this purpose, primary cultures of rat lacrimal gland myoepithelial cells were established and examined functionally. Methods Rat lacrimal glands were excised, minced, and further digested, yielding mixtures of cells that were seeded in culturing flasks. After 4-6 weeks, primary monocultures of myoepithelial cells were established, verified by immunocytochemistry. The cells were stained for all muscarinic receptor subtypes (M1-M5) and examined functionally regarding intracellular [Ca2+] responses upon activation of muscarinic receptors. For methodological verification, purinergic functional responses were also studied. Results Expression of muscarinic receptor subtypes M2-M5 was detected, whereas expression of muscarinic M1 receptors could not be shown. Activation of muscarinic receptors by the non-selective muscarinic agonist methacholine (3 × 10-11-10-3 M) did not cause a significant increase in intracellular [Ca2+]. However, activation of purinergic receptors by the non-selective purinergic agonist ATP (10-8-10-3 M) caused a concentration-dependent increase in intracellular [Ca2+] that could be blocked by the P2 antagonists PPADS and suramin. Conclusions Primary cultures of rat lacrimal gland myoepithelial cells were established that displayed a heterogeneous expression of muscarinic receptors. Purinergic functional responses demonstrated a viable cell population. Upon treatment with methacholine, no significant increase in intracellular [Ca2+] could be detected, indicating that cholinergic activation of myoepithelial cells occurs via other intracellular messengers or is dependent on interaction with other cell types.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::62030ebb70b058ad62946ea3f5dcde7cTest
http://europepmc.org/articles/PMC8458779Test

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High capacity in G protein-coupled receptor signaling

المؤلفون: Alexey Koval, Sven Bergmann, Amiran Keshelava, Vladimir L. Katanaev, Mikhail Kryuchkov, Gonzalo P. Solis, Micha Hersch

المصدر: Nature Communications, Vol 9, Iss 1, Pp 1-8 (2018)
Nature Communications, Vol. 9, No 1 (2018) P. 876
Nature Communications
Nature communications, vol. 9, no. 1, pp. 876

مصطلحات موضوعية: 0301 basic medicine, Agonist, Calcium/metabolism, medicine.drug_class, Science, General Physics and Astronomy, Muscarinic Agonists, General Biochemistry, Genetics and Molecular Biology, Article, Receptors, G-Protein-Coupled, Cell Line, 03 medical and health sciences, Channel capacity, Muscarinic acetylcholine receptor, Receptors, Extracellular, medicine, Humans, Acetylcholine/pharmacology, Cell Membrane/metabolism, HEK293 Cells, Muscarinic Agonists/pharmacology, Receptor, Muscarinic M3/metabolism, Receptors, G-Protein-Coupled/agonists, Receptors, G-Protein-Coupled/metabolism, Signal Transduction/physiology, Receptor, lcsh:Science, G protein-coupled receptor, Receptor, Muscarinic M3, Multidisciplinary, Chemistry, HEK 293 cells, Cell Membrane, Muscarinic M3/metabolism, General Chemistry, G Protein-Coupled Receptor Signaling, Acetylcholine, Cell biology, 030104 developmental biology, G-Protein-Coupled/agonists/metabolism, lcsh:Q, Calcium, Signal Transduction

الوصف: G protein-coupled receptors (GPCRs) constitute a large family of receptors that activate intracellular signaling pathways upon detecting specific extracellular ligands. While many aspects of GPCR signaling have been uncovered through decades of studies, some fundamental properties, like its channel capacity—a measure of how much information a given transmission system can reliably transduce—are still debated. Previous studies concluded that GPCRs in individual cells could transmit around one bit of information about the concentration of the ligands, allowing only for a reliable on or off response. Using muscarinic receptor-induced calcium response measured in individual cells upon repeated stimulation, we show that GPCR signaling systems possess a significantly higher capacity. We estimate the channel capacity of this system to be above two, implying that at least four concentration levels of the agonist can be distinguished reliably. These findings shed light on the basic principles of GPCR signaling.
G protein-coupled receptors (GPCRs) activate intracellular signalling pathways upon extracellular stimulation. Here authors record single cell responses of GPCR signalling which allows the direct estimation of its channel capacity for each cell along with the reproducibility of its response.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4ee81ab46ceaeb5fd3835ad768bf9603Test
https://doaj.org/article/e2b10c70e16e40f196b3c188a5647db1Test

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Cell-Based Reporter Release Assay to Determine the Activity of Calcium-Dependent Neurotoxins and Neuroactive Pharmaceuticals

المؤلفون: Pathe-Neuschäfer-Rube, Andrea, Neuschäfer-Rube, Frank, Püschel, Gerhard P.

المصدر: Toxins
Volume 13
Issue 4
Toxins, Vol 13, Iss 247, p 247 (2021)

الوصف: The suitability of a newly developed cell-based functional assay was tested for the detection of the activity of a range of neurotoxins and neuroactive pharmaceuticals which act by stimulation or inhibition of calcium-dependent neurotransmitter release. In this functional assay, a reporter enzyme is released concomitantly with the neurotransmitter from neurosecretory vesicles. The current study showed that the release of a luciferase from a differentiated human neuroblastoma-based reporter cell line (SIMA-hPOMC1-26-GLuc cells) can be stimulated by a carbachol-mediated activation of the Gq-coupled muscarinic-acetylcholine receptor and by the Ca2+-channel forming spider toxin α-latrotoxin. Carbachol-stimulated luciferase release was completely inhibited by the muscarinic acetylcholine receptor antagonist atropine and α-latrotoxin-mediated release by the Ca2+-chelator EGTA, demonstrating the specificity of luciferase-release stimulation. SIMA-hPOMC1-26-GLuc cells express mainly L- and N-type and to a lesser extent T-type VGCC on the mRNA and protein level. In accordance with the expression profile a depolarization-stimulated luciferase release by a high K+-buffer was effectively and dose-dependently inhibited by L-type VGCC inhibitors and to a lesser extent by N-type and T-type inhibitors. P/Q- and R-type inhibitors did not affect the K+-stimulated luciferase release. In summary, the newly established cell-based assay may represent a versatile tool to analyze the biological efficiency of a range of neurotoxins and neuroactive pharmaceuticals which mediate their activity by the modulation of calcium-dependent neurotransmitter release.
Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe; 1139

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4672e0a16bdfc70bed08b378841bda90Test

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Long-term dexamethasone treatment diminishes store-operated Ca2+ entry in salivary acinar cells

المؤلفون: Shintaro Tsuka, Ryuji Hosokawa, Yuichiro Kusuda, Yusuke Hori, Taro Mukaibo, Chihiro Masaki, Yusuke Kondo, Takashi Munemasa, Yuta Miyagi, Fumiko Aonuma

المصدر: International Journal of Oral Science, Vol 11, Iss 1, Pp 1-8 (2019)
International Journal of Oral Science

الوصف: Corticosteroids are used in the treatment of many diseases; however, they also induce various side effects. Dexamethasone is one of the most potent corticosteroids, and it has been reported to induce the side effect of impaired salivary gland function. This study aimed to evaluate the effects of dexamethasone on mouse submandibular gland function to gain insight into the mechanism of dexamethasone-induced salivary hypofunction. The muscarinic agonist carbachol (CCh) induced salivary secretion and was not affected by short-term dexamethasone treatment but was decreased following long-term dexamethasone administration. The expression levels of the membrane proteins Na+-K+-2Cl− cotransporter, transmembrane member 16A, and aquaporin 5 were comparable between the control and long-term dexamethasone treatment groups. The CCh-induced increase in calcium concentration was significantly lower in the presence of extracellular Ca2+ in the long-term dexamethasone treatment group compared to that in the control group. Furthermore, CCh-induced salivation in the absence of extracellular Ca2+ and Ca2+ ionophore A23187-induced salivation was comparable between the control and long-term dexamethasone treatment groups. Moreover, salivation induced by the Ca2+-ATPase inhibitor thapsigargin was diminished in the long-term dexamethasone treatment group. In summary, these results demonstrate that short-term dexamethasone treatment did not impair salivary gland function, whereas long-term dexamethasone treatment diminished store-operated Ca2+ entry, resulting in hyposalivation in mouse submandibular glands.
Corticosteroids: revealing the mechanism of drug-induced dry mouth Long-term corticosteroid use causes dry mouth by inhibiting calcium movement into salivary gland cells. Corticosteroid use is associated with multiple systemic side effects including salivary inhibition, prompting Yusuke Kondo and a research team from Japan’s Kyushu Dental University to elucidate the reasons why. Submandibular glands taken from mice after six weeks’ treatment with the corticosteroid dexamethasone produced significantly less saliva in ten minutes than a group given just one week’s treatment, or no treatment at all. Further investigation revealed that long-term dexamethasone treatment inhibited the ability of salivary gland cells, known as acinar cells, to transport calcium ions from the exterior to the interior of the cells—an essential mechanism enabling salivation. The study improves our understanding of corticosteroid-induced dry mouth and reveals potential pharmacological targets to enable treatment.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c3b3071c8970201e5d12dcd99b6e5c1dTest
http://link.springer.com/article/10.1038/s41368-018-0031-0Test

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دورية أكاديمية

The Relation of Elevation of Cytosolic Free Calcium to Activation of Membrane Conductance in Rat Parotid Acinar Cells

المؤلفون: Gray, P. T. A.

المصدر: Proceedings of the Royal Society of London. Series B, Biological Sciences, 1989 Jun . 237(1286), 99-107.

الوصول الحر: https://www.jstor.org/stable/2410555Test

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