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Reid C, Romero M, Chang SB, Osman N, Puglisi JL, Wilson CG, Blood AB, Zhang L, Wilson SM. Long-Term Hypoxia Negatively Influences Ca2+ Signaling in Basilar Arterial Myocytes of Fetal and Adult Sheep. Front Physiol 2022; 12:760176. [PMID: 35115953 PMCID: PMC8804533 DOI: 10.3389/fphys.2021.760176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/25/2021] [Indexed: 11/21/2022] Open
Abstract
Cerebral arterial vasoreactivity is vital to the regulation of cerebral blood flow. Depolarization of arterial myocytes elicits whole-cell Ca2+ oscillations as well as subcellular Ca2+ sparks due to activation of ryanodine receptors on the sarcoplasmic reticulum. Previous evidence illustrates that contraction of cerebral arteries from sheep and underlying Ca2+ signaling pathways are modified by age and that long-term hypoxia (LTH) causes aberrations in Ca2+ signaling pathways and downstream effectors impacting vasoregulation. We hypothesize that age and LTH affect the influence of membrane depolarization on whole-cell intracellular Ca2+ oscillations and sub-cellular Ca2+ spark activity in cerebral arteries. To test this hypothesis, we examined Ca2+ oscillatory and spark activities using confocal fluorescence imaging techniques of Fluo-4 loaded basilar arterial myocytes of low- and high-altitude term fetal (∼145 days of gestation) and adult sheep, where high-altitude pregnant and non-pregnant sheep were placed at 3,801 m for >100 days. Ca2+ oscillations and sparks were recorded using an in situ preparation evaluated in the absence or presence of 30 mM K+ (30K) to depolarize myocytes. Myocytes from adult animals tended to have a lower basal rate of whole-cell Ca2+ oscillatory activity and 30K increased the activity within cells. LTH decreased the ability of myocytes to respond to depolarization independent of age. These observations illustrate that both altitude and age play a role in affecting whole-cell and localized Ca2+ signaling, which are important to arterial vasoreactivity and cerebral blood flow.
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Affiliation(s)
- Casey Reid
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Monica Romero
- Advanced Imaging and Microscopy Core, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Stephanie B. Chang
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Noah Osman
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Jose L. Puglisi
- Department of Biostatistics, School of Medicine, California Northstate University, Elk Grove, CA, United States
| | - Christopher G. Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Arlin B. Blood
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Lubo Zhang
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Sean M. Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, United States
- Advanced Imaging and Microscopy Core, Loma Linda University School of Medicine, Loma Linda, CA, United States
- *Correspondence: Sean M. Wilson,
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Puig-Oliveras A, Ballester M, Corominas J, Revilla M, Estellé J, Fernández AI, Ramayo-Caldas Y, Folch JM. A co-association network analysis of the genetic determination of pig conformation, growth and fatness. PLoS One 2014; 9:e114862. [PMID: 25503799 PMCID: PMC4263716 DOI: 10.1371/journal.pone.0114862] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/14/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Several QTLs have been identified for major economically relevant traits in livestock, such as growth and meat quality, revealing the complex genetic architecture of these traits. The use of network approaches considering the interactions of multiple molecules and traits provides useful insights into the molecular underpinnings of complex traits. Here, a network based methodology, named Association Weight Matrix, was applied to study gene interactions and pathways affecting pig conformation, growth and fatness traits. RESULTS The co-association network analysis underpinned three transcription factors, PPARγ, ELF1, and PRDM16 involved in mesoderm tissue differentiation. Fifty-four genes in the network belonged to growth-related ontologies and 46 of them were common with a similar study for growth in cattle supporting our results. The functional analysis uncovered the lipid metabolism and the corticotrophin and gonadotrophin release hormone pathways among the most important pathways influencing these traits. Our results suggest that the genes and pathways here identified are important determining either the total body weight of the animal and the fat content. For instance, a switch in the mesoderm tissue differentiation may determinate the age-related preferred pathways being in the puberty stage those related with the miogenic and osteogenic lineages; on the contrary, in the maturity stage cells may be more prone to the adipocyte fate. Hence, our results demonstrate that an integrative genomic co-association analysis is a powerful approach for identifying new connections and interactions among genes. CONCLUSIONS This work provides insights about pathways and key regulators which may be important determining the animal growth, conformation and body proportions and fatness traits. Molecular information concerning genes and pathways here described may be crucial for the improvement of genetic breeding programs applied to pork meat production.
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Affiliation(s)
- Anna Puig-Oliveras
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
| | - Maria Ballester
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
| | - Jordi Corominas
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
| | - Manuel Revilla
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
| | - Jordi Estellé
- Génétique Animale et Biologie Intégrative UMR1313 (GABI), Institut National de la Recherche Agronomique (INRA), 78350, Jouy-en-Josas, France
- Génétique Animale et Biologie Intégrative UMR1313 (GABI), AgroParisTech, 78350, Jouy-en-Josas, France
- Laboratoire de Radiobiologie et Etude du Génome (LREG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 78350, Jouy-en-Josas, France
| | - Ana I. Fernández
- Departamento de Genética Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040, Madrid, Spain
| | - Yuliaxis Ramayo-Caldas
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
- Génétique Animale et Biologie Intégrative UMR1313 (GABI), Institut National de la Recherche Agronomique (INRA), 78350, Jouy-en-Josas, France
- Génétique Animale et Biologie Intégrative UMR1313 (GABI), AgroParisTech, 78350, Jouy-en-Josas, France
- Laboratoire de Radiobiologie et Etude du Génome (LREG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 78350, Jouy-en-Josas, France
| | - Josep M. Folch
- Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona (UAB), 08193, Bellaterra, Spain
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG), 08193, Bellaterra, Spain
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Papamatheakis DG, Chundu M, Blood AB, Wilson SM. Prenatal programming of pulmonary hypertension induced by chronic hypoxia or ductal ligation in sheep. Pulm Circ 2014; 3:757-80. [PMID: 25006393 DOI: 10.1086/674767] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 07/28/2013] [Indexed: 11/03/2022] Open
Abstract
Pulmonary hypertension of the newborn is caused by a spectrum of functional and structural abnormalities of the cardiopulmonary circuit. The existence of multiple etiologies and an incomplete understanding of the mechanisms of disease progression have hindered the development of effective therapies. Animal models offer a means of gaining a better understanding of the fundamental basis of the disease. To that effect, a number of experimental animal models are being used to generate pulmonary hypertension in the fetus and newborn. In this review, we compare the mechanisms associated with pulmonary hypertension caused by two such models: in utero ligation of the ductus arteriosus and chronic perinatal hypoxia in sheep fetuses and newborns. In this manner, we make direct comparisons between ductal ligation and chronic hypoxia with respect to the associated mechanisms of disease, since multiple studies have been performed with both models in a single species. We present evidence that the mechanisms associated with pulmonary hypertension are dependent on the type of stress to which the fetus is subjected. Such an analysis allows for a more thorough evaluation of the disease etiology, which can help focus clinical treatments. The final part of the review provides a clinical appraisal of current treatment strategies and lays the foundation for developing individualized therapies that depend on the causative factors.
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Affiliation(s)
- Demosthenes G Papamatheakis
- Division of Pulmonary and Critical Care, University of California San Diego Health System, San Diego, California, USA
| | - Madalitso Chundu
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Arlin B Blood
- Department of Pediatrics Division of Neonatology, and Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Sean M Wilson
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California, USA
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Lu M, Farnebo LO, Bränström R, Larsson C. Inhibition of parathyroid hormone secretion by caffeine in human parathyroid cells. J Clin Endocrinol Metab 2013; 98:E1345-51. [PMID: 23788688 PMCID: PMC4207951 DOI: 10.1210/jc.2013-1466] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
CONTEXT AND OBJECTIVE Caffeine is a highly consumed psychoactive substance present in our daily drinks. Independent studies have reported associations between caffeine consumption, low bone mineral density, and urinary calcium loss, as well as impaired bone development in vitro and in vivo. Calcium (Ca(2+)), vitamin D, and PTH are critical regulators of bone remodeling. A possible association between caffeine and parathyroid gland function has been suggested in the literature. DESIGN, SETTING, AND PATIENTS Effects of caffeine on PTH secretion and Ca(2+) levels were determined by batch incubation and Fura-2, respectively, in pathological parathyroid cells. Protein expressions were studied by Western blot and immunohistochemistry in normal and parathyroid adenoma tissues. Alterations in gene expressions of adenosine receptor A1 (ADORA1) and A2 (ADORA2A) and PTH were quantified by PCR; intracellular cAMP levels and protein kinase A activity were analyzed by an antibody-based assay. RESULTS We studied physiological concentrations of caffeine ranging from 1 to 50 μm and found that 50 μm caffeine caused a significant decrease of PTH secretion and PTH gene expression. This decrease occurred in parallel with a decrease of the intracellular cAMP level, protein kinase A activity, and ADORA1 gene expression, indicating a possible causal relationship. The intracellular level of Ca(2+) was unaffected even by high concentrations of caffeine. Protein expressions demonstrated two main targets for caffeine-ADORA1 and ADORA2A. CONCLUSION A physiological high dose of caffeine inhibits PTH secretion in human parathyroid cells, possibly due to a decrease of the intracellular level of cAMP. The observation demonstrates a functional link between caffeine and parathyroid cell function.
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Affiliation(s)
- Ming Lu
- Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
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Hadley SR, Blood Q, Rubalcava M, Waskel E, Lumbard B, Le P, Longo LD, Buchholz JN, Wilson SM. Maternal high-altitude hypoxia and suppression of ryanodine receptor-mediated Ca2+ sparks in fetal sheep pulmonary arterial myocytes. Am J Physiol Lung Cell Mol Physiol 2012; 303:L799-813. [PMID: 22962012 DOI: 10.1152/ajplung.00009.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Ca(2+) sparks are fundamental Ca(2+) signaling events arising from ryanodine receptor (RyR) activation, events that relate to contractile and dilatory events in the pulmonary vasculature. Recent studies demonstrate that long-term hypoxia (LTH) can affect pulmonary arterial reactivity in fetal, newborn, and adult animals. Because RyRs are important to pulmonary vascular reactivity and reactivity changes with ontogeny and LTH we tested the hypothesis that RyR-generated Ca(2+) signals are more active before birth and that LTH suppresses these responses. We examined these hypotheses by performing confocal imaging of myocytes in living arteries and by performing wire myography studies. Pulmonary arteries (PA) were isolated from fetal, newborn, or adult sheep that lived at low altitude or from those that were acclimatized to 3,801 m for > 100 days. Confocal imaging demonstrated preservation of the distance between the sarcoplasmic reticulum, nucleus, and plasma membrane in PA myocytes. Maturation increased global Ca(2+) waves and Ca(2+) spark activity, with sparks becoming larger, wider, and slower. LTH preferentially depressed Ca(2+) spark activity in immature pulmonary arterial myocytes, and these sparks were smaller, wider, and slower. LTH also suppressed caffeine-elicited contraction in fetal PA but augmented contraction in the newborn and adult. The influence of both ontogeny and LTH on RyR-dependent cell excitability shed new light on the therapeutic potential of these channels for the treatment of pulmonary vascular disease in newborns as well as adults.
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Affiliation(s)
- Scott R Hadley
- Center for Perinatal Biology, Loma Linda University, California 92350, USA
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6
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De Grazia S, Carlomagno G, Unfer V, Cavalli P. Myo-inositol soft gel capsules may prevent the risk of coffee-induced neural tube defects. Expert Opin Drug Deliv 2012; 9:1033-9. [DOI: 10.1517/17425247.2012.701616] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Kim EJ, Kim DK, Kim SH, Lee KM, Park HS, Kim SH. Alteration of Ryanodine-receptors in Cultured Rat Aortic Smooth Muscle Cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:431-6. [PMID: 22359482 PMCID: PMC3282232 DOI: 10.4196/kjpp.2011.15.6.431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 11/25/2011] [Accepted: 11/25/2011] [Indexed: 12/02/2022]
Abstract
Vascular smooth muscle cells can obtain a proliferative function in environments such as atherosclerosis in vivo or primary culture in vitro. Proliferation of vascular smooth muscle cells is accompanied by changes in ryanodine receptors (RyRs). In several studies, the cytosolic Ca2+ response to caffeine is decreased during smooth muscle cell culture. Although caffeine is commonly used to investigate RyR function because it is difficult to measure Ca2+ release from the sarcoplasmic reticulum (SR) directly, caffeine has additional off-target effects, including blocking inositol trisphosphate receptors and store-operated Ca2+ entry. Using freshly dissociated rat aortic smooth muscle cells (RASMCs) and cultured RASMCs, we sought to provide direct evidence for the operation of RyRs through the Ca2+- induced Ca2+-release pathway by directly measuring Ca2+ release from SR in permeabilized cells. An additional goal was to elucidate alterations of RyRs that occurred during culture. Perfusion of permeabilized, freshly dissociated RASMCs with Ca2+ stimulated Ca2+ release from the SR. Caffeine and ryanodine also induced Ca2+ release from the SR in dissociated RASMCs. In contrast, ryanodine, caffeine and Ca2+ failed to trigger Ca2+ release in cultured RASMCs. These results are consistent with results obtained by immunocytochemistry, which showed that RyRs were expressed in dissociated RASMCs, but not in cultured RASMCs. This study is the first to demonstrate Ca2+ release from the SR by cytosolic Ca2+ elevation in vascular smooth muscle cells, and also supports previous studies on the alterations of RyRs in vascular smooth muscle cells associated with culture.
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Affiliation(s)
- Eun Ji Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 302-718, Korea
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8
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Mice null for calsequestrin 1 exhibit deficits in functional performance and sarcoplasmic reticulum calcium handling. PLoS One 2011; 6:e27036. [PMID: 22164205 PMCID: PMC3229475 DOI: 10.1371/journal.pone.0027036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 10/09/2011] [Indexed: 01/06/2023] Open
Abstract
In skeletal muscle, the release of calcium (Ca2+) by ryanodine sensitive sarcoplasmic reticulum (SR) Ca2+ release channels (i.e., ryanodine receptors; RyR1s) is the primary determinant of contractile filament activation. Much attention has been focused on calsequestrin (CASQ1) and its role in SR Ca2+ buffering as well as its potential for modulating RyR1, the L-type Ca2+ channel (dihydropyridine receptor, DHPR) and other sarcolemmal channels through sensing luminal [Ca2+]. The genetic ablation of CASQ1 expression results in significant alterations in SR Ca2+ content and SR Ca2+ release especially during prolonged activation. While these findings predict a significant loss-of-function phenotype in vivo, little information on functional status of CASQ1 null mice is available. We examined fast muscle in vivo and in vitro and identified significant deficits in functional performance that indicate an inability to sustain contractile activation. In single CASQ1 null skeletal myofibers we demonstrate a decrease in voltage dependent RyR Ca2+ release with single action potentials and a collapse of the Ca2+ release with repetitive trains. Under voltage clamp, SR Ca2+ release flux and total SR Ca2+ release are significantly reduced in CASQ1 null myofibers. The decrease in peak Ca2+ release flux appears to be solely due to elimination of the slowly decaying component of SR Ca2+ release, whereas the rapidly decaying component of SR Ca2+ release is not altered in either amplitude or time course in CASQ1 null fibers. Finally, intra-SR [Ca2+] during ligand and voltage activation of RyR1 revealed a significant decrease in the SR[Ca2+]free in intact CASQ1 null fibers and a increase in the release and uptake kinetics consistent with a depletion of intra-SR Ca2+ buffering capacity. Taken together we have revealed that the genetic ablation of CASQ1 expression results in significant functional deficits consistent with a decrease in the slowly decaying component of SR Ca2+ release.
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Fonseca-Magalhães PA, Sousa DF, de Siqueira RJB, Jorge RJB, Meneses GC, Alves RS, Monteiro HSA, Magalhães PJC, Martins AMC. Inhibitory effects of sertraline in rat isolated perfused kidneys and in isolated ring preparations of rat arteries. J Pharm Pharmacol 2011; 63:1186-94. [DOI: 10.1111/j.2042-7158.2011.01317.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract
Objectives
Sertraline is often prescribed to patients suffering with end stage renal disease, but its action on kidney has not been investigated. We aimed to investigate the pharmacological action of sertraline on rat kidney with emphasis on the underlying mechanisms involved in the vascular actions of the drug.
Methods
The effects of sertraline were evaluated in rat isolated perfused kidneys and on ring preparations of mesenteric or segmental rat renal artery.
Key findings
In kidneys, sertraline prevented the effects of phenylephrine on perfusion pressure, glomerular filtration rate, urinary flow and renal vascular resistance. In mesenteric rings sertraline inhibited phenylephrine-induced contractions with potency 30-times lower than verapamil. Sertraline reversed sustained contractions induced by phenylephrine or 60 mm K+ within a similar concentration range. In segmental isolated rings, sertraline also reversed contractions induced by phenylephrine or 60 mm K+ with the same concentration range, but with higher potency compared with mesenteric preparations. Under Ca2+-free conditions, sertraline did not change the intracellularly-mediated phasic contractions induced by phenylephrine or caffeine. Sertraline was ineffective against contractions induced by extracellular Ca2+ restoration after thapsigargin treatment and Ca2+ store depletion with phenylephrine. Conversely, sertraline decreased the contractions induced by Ca2+ addition in tissues under high K+ solution or phenylephrine plus verapamil.
Conclusions
In rat isolated kidneys and in rat ring preparations of mesenteric or renal vessels, sertraline had antispasmodic effects that appeared to be caused by a direct action on vascular smooth muscle cells. Its actions were ineffective against Ca2+-releasing intracellular pathways, but appeared to interfere with sarcolemmal Ca2+ influx with reduced permeability of both receptor- and voltage-gated Ca2+ channels.
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Affiliation(s)
| | - Daniel F Sousa
- Departamento de Fisiologia e Farmacologia, Ceará, Brasil
| | | | | | - Gdayllon C Meneses
- Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Ceará, Brasil
| | - Renata S Alves
- Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Ceará, Brasil
| | | | | | - Alice M C Martins
- Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Ceará, Brasil
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Xue JH, Chen LH, Zhao HZ, Pu YD, Feng HZ, Ma YG, Ma J, Chang YM, Zhang ZM, Xie MJ. Differential regulation and recovery of intracellular Ca2+ in cerebral and small mesenteric arterial smooth muscle cells of simulated microgravity rat. PLoS One 2011; 6:e19775. [PMID: 21611118 PMCID: PMC3097196 DOI: 10.1371/journal.pone.0019775] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 04/05/2011] [Indexed: 01/15/2023] Open
Abstract
Background The differential adaptations of cerebrovasculature and small mesenteric arteries could be one of critical factors in postspaceflight orthostatic intolerance, but the cellular mechanisms remain unknown. We hypothesize that there is a differential regulation of intracellular Ca2+ determined by the alterations in the functions of plasma membrane CaL channels and ryanodine-sensitive Ca2+ releases from sarcoplasmic reticulum (SR) in cerebral and small mesenteric vascular smooth muscle cells (VSMCs) of simulated microgravity rats, respectively. Methodology/Principal Findings Sprague-Dawley rats were subjected to 28-day hindlimb unweighting to simulate microgravity. In addition, tail-suspended rats were submitted to a recovery period of 3 or 7 days after removal of suspension. The function of CaL channels was evaluated by patch clamp and Western blotting. The function of ryanodine-sensitive Ca2+ releases in response to caffeine were assessed by a laser confocal microscope. Our results indicated that simulated microgravity increased the functions of CaL channels and ryanodine-sensitive Ca2+ releases in cerebral VSMCs, whereas, simulated microgravity decreased the functions of CaL channels and ryanodine-sensitive Ca2+ releases in small mesenteric VSMCs. In addition, 3- or 7-day recovery after removal of suspension could restore the functions of CaL channels and ryanodine-sensitive Ca2+ releases to their control levels in cerebral and small mesenteric VSMCs, respectively. Conclusions The differential regulation of CaL channels and ryanodine-sensitive Ca2+ releases in cerebral and small mesenteric VSMCs may be responsible for the differential regulation of intracellular Ca2+, which leads to the altered autoregulation of cerebral vasculature and the inability to adequately elevate peripheral vascular resistance in postspaceflight orthostatic intolerance.
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Affiliation(s)
- Jun-Hui Xue
- Department of Aerospace Clinical Medicine, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Lian-Hong Chen
- Department of Chest Surgery, Tangdu Hospital of Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Hua-Zhou Zhao
- 309 Clinical Divisions, Department of General Surgery, General Hospital of PLA, Beijing, China
| | - Yong-Dong Pu
- 309 Clinical Divisions, Department of General Surgery, General Hospital of PLA, Beijing, China
| | - Han-Zhong Feng
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Yu-Guang Ma
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Jin Ma
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Yao-Ming Chang
- Department of Aerospace Clinical Medicine, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
| | - Zuo-Ming Zhang
- Department of Aerospace Clinical Medicine, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
- * E-mail: (Z-MZ); (M-JX)
| | - Man-Jiang Xie
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Fourth Military Medical University, Xi'an, Shaanxi Province, China
- * E-mail: (Z-MZ); (M-JX)
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11
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Kobayashi M, Mukaida K, Migita T, Hamada H, Kawamoto M, Yuge O. Analysis of human cultured myotubes responses mediated by ryanodine receptor 1. Anaesth Intensive Care 2011; 39:252-61. [PMID: 21485675 DOI: 10.1177/0310057x1103900216] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Malignant hyperthermia is a life-threatening condition caused by autosomal dominant mutations in the ryanodine receptor type 1 gene. Identifying patients predisposed to malignant hyperthermia is done through the Ca-induced Ca release test in Japan. We examined the intracellular calcium concentration in human cultured muscle cells and compared the sensitivity of myotubes to ryanodine receptor type 1 activators based on the Ca-induced Ca release rate. We assessed the utility of this method as an identifying test for predisposition to malignant hyperthermia. Muscle specimens were obtained from 34 individuals undergoing the Ca-induced Ca release test. We cultured myotubes from residual material and monitored changes in intracellular calcium concentration after exposure to the ryanodine receptor type 1 activators caffeine, halothane and 4-chloro-m-cresol by measuring fura-2 fluorescence. We determined the half maximal effective concentrations (EC50) for the test compounds in each myotube and calculated cut-off points using receiver operating characteristic curves. Seventeen patients each were classified into the accelerated and non-accelerated groups based on their Ca-induced Ca release rate. The EC50 values for caffeine, halothane and 4-chloro-m-cresol of the accelerated group were significant lower than those of the non-accelerated group (P < 0.001, P < 0.001 and P < 0.001, respectively). The calculated cut-off points of EC50 values for caffeine, halothane and 4-CmC were 3.62 mM, 2.28 mM and 197 microM, respectively. An increased sensitivity to ryanodine receptor type 1 activators was seen in myotubes in the accelerated group. This functional test on human cultured myotubes indicates that the alteration of their intracellular Ca2+ homeostasis may identify the predisposition to malignant hyperthermia.
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Affiliation(s)
- M Kobayashi
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima, Japan.
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